convertto.tech

Turn a phrase into an acronym or initialism, with control over small words and separators.

Prefix every line with a sequential number, with a custom start, separator and zero padding.

Work out exact age in years, months and days — plus total days and the next birthday.

Turn an agenda into a timed schedule with start and end times for every item.

Generate the robots.txt rules for 21 AI crawlers, separating training from search and from fetches a real user asked for.

Find images with missing, empty, filename-based or overlong alternative text.

Convert angle between 7 units with the formula, a reverse conversion and a quick-reference table.

Build an HTTP request visually and get it as curl, fetch, axios, Python, Go or PHP code.

Convert area between 10 units with the formula, a reverse conversion and a quick-reference table.

Search ARIA roles with their required attributes, native HTML equivalents and gotchas.

Turn words into large ASCII banner text for terminals, READMEs and code comments.

Turn CSV or tab-separated text into an aligned plain-text, Markdown or box-drawing table.

Work out the aspect ratio of any dimensions and scale them proportionally.

Encode and decode Base32 (RFC 4648) — used by TOTP secrets and case-insensitive identifiers.

Encode and decode Base58 — the Bitcoin alphabet that omits look-alike characters.

Split a bill evenly or by what each person ordered, with tip and tax handled correctly.

Convert binary numbers to decimal, hex and octal instantly.

Translate text into binary ones and zeros, and decode binary back into readable text.

Generate unique bingo cards from your own list of items, with an optional free space.

Bold the leading letters of each word to guide the eye through long text.

Design organic SVG backgrounds: four interpolation styles, gradients, layers and any canvas size.

Calculate body mass index in metric or imperial units, with the WHO categories.

Estimate your basal metabolic rate and daily calorie needs using Mifflin-St Jeor.

Estimate body fat percentage using the US Navy tape-measure method.

Drag eight handles to shape every corner: elliptical radii, inverted corners and squircles.

Design a CSS box-shadow with live values for offset, blur, spread and colour.

Find how many units you must sell to cover your costs.

Encrypt and decrypt text with a Caesar shift cipher, including ROT13.

Compound annual growth rate between two values, with the year-by-year path.

Turn a daily calorie target into a weekly deficit, a projected rate of change and a per-meal split.

Convert text to UPPERCASE, lowercase, Title Case, camelCase, snake_case, kebab-case and more.

Convert an identifier between every common naming convention at once.

Turn a plain list into Markdown task lists, HTML checkboxes or a numbered outline.

Convert clothing size between 6 units with the formula, a reverse conversion and a quick-reference table.

Strip whitespace and comments to shrink HTML, CSS and JavaScript for production.

See how a colour appears to people with protanopia, deuteranopia and tritanopia.

Convert any colour to HEX, RGB, HSL, HSV, CMYK, LAB and native code — with contrast, tints and harmonies.

Blend two colours and generate the intermediate steps between them.

Build harmonious palettes — complementary, triadic, analogous and monochromatic.

Generate lighter tints and darker shades of any colour, with hex values.

Switch between a delimited single line and one item per line, in either direction.

Strip comments from six language families without breaking string literals.

Project savings growth with compound interest and regular contributions.

Check colour contrast against WCAG AA and AAA thresholds for accessible text.

Convert cooking measurement between 10 units with the formula, a reverse conversion and a quick-reference table.

Count down to any date and see the gap in years, months, weeks, days, hours and minutes.

Calculate a CRC32 checksum — the fast error-detection code used in ZIP and PNG files.

Translate a cron expression into plain English and see when it will next run.

See the next fire times for a cron expression, with each field explained.

Build a CSP header from common presets, with each directive explained.

Generate keyframe animations — fade, slide, bounce, pulse, spin and shake.

Design a button and copy the CSS, including the hover, active and focus-visible states.

Generate fluid clamp() values that scale smoothly between two viewport widths.

Cut an element to a polygon, circle, ellipse or inset, and copy the clip-path.

Flow text into balanced columns with a rule between them.

Hover to try every CSS cursor keyword, and copy the one you want.

Build a CSS filter chain visually and see it applied to a real element as you adjust it.

Format stylesheets with consistent indentation, spacing and property ordering.

Build a CSS Grid layout visually and copy the container CSS.

Generate a hover effect that animates cleanly, with the reduced-motion guard included.

Build a spinner, dots, bars or a pulse from pure CSS and copy the keyframes.

Every CSS colour name with its HEX, RGB, HSL and OKLCH value, sortable by hue and contrast.

Generate repeating background patterns in pure CSS — no image files to host.

Style a scrollbar with both the standard properties and the WebKit pseudo-elements.

Generate triangles, arrows, stars and other shapes using pure CSS.

Work out a selector's specificity and see which parts contributed what.

Generate a tooltip from a data attribute — no JavaScript, no extra markup.

Build a 2D or 3D transform visually and copy the CSS, with the transform origin handled properly.

Profile a CSV: column types, missing values, ranges, distinct counts and outliers.

Pull selected columns out of a CSV by name or position, and reorder them.

Remove duplicate rows from a CSV, matching on every column or just a key you choose.

Join two CSV files on a shared key, or stack them, with inner, left and outer joins.

Split a CSV into chunks of N rows, or into separate files grouped by a column value.

View CSV data as a sortable table and export it as JSON or a Markdown table.

Build custom CSS easing curves and see the motion they produce.

Turn a cURL command into fetch, axios, Python requests or Node.js code.

Mask, hash or replace personal data in a CSV so it can be shared safely.

Pull emails, URLs, IP addresses, phone numbers or hashtags out of any text.

Convert between JSON, YAML, XML, CSV, TSV and TOML in any direction, locally in your browser.

Convert data size between 11 units with the formula, a reverse conversion and a quick-reference table.

Convert transfer rate between 8 units with the formula, a reverse conversion and a quick-reference table.

Turn text, SVG or CSS into a data: URI you can inline directly in HTML or stylesheets.

Find the date a set number of days, weeks, months or years before or after another.

Count the days, weeks, months and working days between two dates.

Reformat a list of dates into ISO, US, European, RFC or any custom pattern.

Find the ordinal day number, week number, quarter and how much of the year has elapsed.

Compare snowball and avalanche repayment strategies across several debts.

Score options against weighted criteria and see which choice actually wins.

Convert density between 6 units with the formula, a reverse conversion and a quick-reference table.

Straight-line, declining balance, double-declining and sum-of-years depreciation schedules.

Roll dice notation like 3d6+2 and see the full probability distribution.

Roll any number of dice with any number of sides, plus a modifier.

Compare two texts and highlight exactly what was added and removed.

Produce a unified diff between two texts that git apply and patch can consume.

Work out sale prices, stacked discounts and how much you actually save.

Add, subtract and average durations written as 1h 30m, 90:00 or 1:30:00.

Generate the strings that break input handling — Unicode, RTL, emoji, injection patterns and boundary lengths.

Paste raw email headers to map the delivery path, time every hop and read the SPF, DKIM and DMARC results the receiving server recorded.

Size an emergency fund from your real monthly outgoings and see how long it takes to build.

Search emoji by name and copy them, with their Unicode code points.

Convert energy between 9 units with the formula, a reverse conversion and a quick-reference table.

Check a .env file for syntax errors, duplicate keys, exposed secrets and missing entries.

Convert .env files to JSON and back — for config migrations and CI variables.

Calculate powers, nth roots, logarithms in any base, and exponentials.

Generate valid-format test addresses for six countries, with correct postcode and phone patterns.

Convert text into bold, italic, script, monospace and double-struck Unicode styles.

Work out what a fixed deposit matures to, with quarterly compounding and TDS accounted for.

Replace text across a whole document with plain matching or full regular expressions.

Experiment with flex direction, alignment and wrapping, then copy the CSS.

Convert force between 6 units with the formula, a reverse conversion and a quick-reference table.

Add, subtract, multiply and divide fractions, with the result simplified.

Convert fractions to decimals and decimals back to simplified fractions.

Work out the hourly and day rate you need to hit a target income after time off, costs and tax.

Convert frequency between 6 units with the formula, a reverse conversion and a quick-reference table.

Convert fuel economy between 5 units with the formula, a reverse conversion and a quick-reference table.

Find the greatest common divisor and lowest common multiple of any set of numbers.

Work out the download size of a quantised model at every GGUF level, and what quality each one costs you.

Build the exact git command for fifteen common tasks, with explanations and safety notes.

Build a .gitignore file for your stack, with the entries people usually forget.

Create frosted-glass CSS with backdrop blur, transparency and a subtle border.

Create corrupted Zalgo-style glitch text using stacked Unicode combining marks.

Build linear, radial and conic CSS gradients and copy the code.

Fill text with a gradient, a metallic sheen or a chrome effect using background-clip.

Format or minify a GraphQL query, mutation or schema, and inspect its depth.

Add GST to a price or work backwards from a GST-inclusive total, with the CGST/SGST split.

Turn keywords and phrases into properly formatted hashtags.

Check a page for skipped heading levels, missing or multiple H1s and empty headings.

Calculate your training zones from maximum and resting heart rate.

Convert hexadecimal values to decimal, binary and octal.

Convert text to hexadecimal bytes and decode hex strings back into readable text.

Generate an HMAC signature with SHA-256, SHA-1, SHA-384 or SHA-512 and a secret key.

Convert characters to HTML entities and back — escape markup safely for display.

Format and indent HTML properly, preserving inline elements and whitespace sensitivity.

Check a page for the landmark regions screen reader users navigate by.

Paste response headers and get a security grade, with what is missing and why it matters.

Look up what any HTTP status code means and when to use it.

Convert illuminance between 5 units with the formula, a reverse conversion and a quick-reference table.

See what an amount of money is worth after inflation over any period.

Parse INI, .conf, .cfg and .properties files into structured JSON, YAML or TOML.

Format JavaScript, TypeScript, JSX and TSX properly with Prettier.

Compare two JSON documents and see exactly which keys were added, removed or changed.

Flatten deeply nested JSON into dot-notation keys, or expand flat keys back into nested objects.

Format, validate, repair and analyse JSON — with errors that point at the exact line.

Deep-merge several JSON documents, choosing how arrays and conflicts are resolved.

Infer a JSON Schema from example data, detecting types, string formats and required keys.

Sort object keys and arrays in a JSON document to make two versions comparable.

Generate TypeScript interfaces, Zod schemas, Go structs, Python dataclasses or Rust structs from JSON.

Check whether JSON is valid, with the precise position of the error and what usually causes it.

Run JSONPath expressions against a document and see the matches instantly.

Decode a JSON Web Token to inspect its header, payload and expiry — locally, never sent anywhere.

Verify a JWT's HS256 signature and its expiry, issuer and audience claims, entirely in your browser.

Analyse which words and phrases dominate your content, and how often they appear.

Check whether a year is a leap year and see the next and previous ones, with the rule explained.

Convert normal text into 1337 5p34k, with light or heavy substitution.

Convert length between 14 units with the formula, a reverse conversion and a quick-reference table.

Count letter and character frequencies — useful for cryptograms and puzzle solving.

Convert between CRLF, LF and CR, and strip trailing whitespace.

Sort lines alphabetically, numerically, by length or in reverse — with natural-order support.

Add a prefix and suffix to every line and join them — build SQL IN lists, arrays and CSV rows.

Find vague link wording — "click here", "read more", bare URLs and duplicated labels.

Find items in both lists, in one only, or combined — union, intersection and difference.

Shuffle a list into random order — for draws, pairings, running orders and sampling.

Every current model side by side: price per million tokens, context window, max output, modalities and cache rates.

Work out exactly how much video memory a local model needs, including the KV cache that scales with context length.

Build a valid llms.txt: a curated, Markdown map of your site written for a model with a limited context window.

Calculate monthly repayments, total interest and the full cost of a loan.

Parse Apache, Nginx or JSON log lines into a sortable table with traffic summaries.

Generate placeholder text in paragraphs, sentences, words or list items.

Generate random lottery lines for common draws, with the real odds shown.

Split daily calories into protein, carbohydrate and fat targets in grams.

Write markdown with a live preview, outline, formatting toolbar and one-click HTML, PDF or .md export.

Tidy Markdown — normalise headings, lists, tables and emphasis markers.

Convert Markdown to clean HTML, or turn existing HTML back into Markdown.

Convert between markup and margin — they are not the same number, and confusing them costs money.

Generate responsive breakpoint media queries, with common device presets.

Work out what a meeting actually costs in salary time, per session and per year.

Generate title, description, Open Graph and Twitter Card tags for any page.

Find the correct MIME type for any file extension, and vice versa.

Generate realistic fake test data in 14 formats from 100+ field types, with reproducible seeds.

Find the moon phase, illumination and age for any date, plus the upcoming new and full moons.

Translate text to Morse code and decode Morse back to plain text, letters and numbers included.

Compare two loan offers side by side — payment, total interest and the true cost with fees.

Encode text into Base64, hex, binary, URL, HTML entities, ROT13 and more, all at once.

Generate compact URL-safe unique IDs — shorter than a UUID with comparable collision safety.

Spell any word using the NATO phonetic alphabet — Alfa, Bravo, Charlie — for clear radio and phone use.

Generate the paired light and dark shadows that make an element look pressed into or raised from its background.

Net present value, internal rate of return and payback period for a series of cash flows.

Build an :nth-child formula and see which items it selects out of a row.

Convert numbers between any base from 2 to 36 — binary, octal, decimal, hexadecimal and beyond.

Spell out numbers in English words — for cheques, contracts and invoices.

Convert octal numbers to decimal, binary and hexadecimal.

Convert numbers to ordinals — 1st, first, primary, Roman — with the irregular cases right.

Grade every colour in a palette against one or more backgrounds for WCAG contrast.

Generate memorable Diceware-style passphrases from random words.

Generate strong random passwords using your browser's cryptographic random source.

Test a password against a policy and see whether the policy actually improves security.

Estimate how long a password would take to crack, and see exactly what weakens it.

Work out percentages, percentage change and reverse percentages with the working shown.

Convert between percentages, decimals, fractions, ratios and basis points.

Calculate nPr, nCr and factorials for counting and probability problems.

Convert English to Pig Latin and back, with both the classic and consonant-cluster rules.

Convert power between 7 units with the formula, a reverse conversion and a quick-reference table.

Estimate a due date from a last period, conception date or an early scan, with milestones.

Convert pressure between 10 units with the formula, a reverse conversion and a quick-reference table.

Check whether a number is prime and see its full prime factorisation.

Calculate margin, markup and profit from cost and selling price — they are not the same thing.

Convert internationalised domain names to Punycode and decode xn-- domains back.

Convert between pixels, rem and em using your project root font size.

Solve ax² + bx + c = 0 with real or complex roots and see the discriminant.

Convert URL query strings to JSON and build query strings from JSON objects.

Encode and decode quoted-printable, the MIME format used in email bodies and headers.

Generate random colours as a free palette or a harmony built around a base colour.

Generate random dates in a range, optionally restricted to working days.

Generate random numbers in any range, with optional uniqueness — for draws and sampling.

Pick winners from a list, or split names into balanced random teams.

Generate random strings from a chosen character set — for keys, tokens and test data.

Split a list of people into balanced random teams, by team count or team size.

Simplify ratios, scale them, and solve for a missing value in a proportion.

Work out what a monthly recurring deposit matures to, with quarterly compounding.

Score text with Flesch, Gunning Fog, SMOG, Coleman-Liau and ARI, and see the reading age.

Generate redirect rules for Apache, Nginx, Netlify, Vercel and Next.js.

Break a regular expression into tokens and explain each one in plain English.

Test regular expressions against sample text and see every match with its capture groups.

Convert accented characters to plain ASCII — café becomes cafe, naïve becomes naive.

Delete repeated lines from a list, keeping the first occurrence of each unique line.

Turn multi-line text into a single line, joining with a space, comma or custom separator.

Compare the total cost of renting against buying over a period you choose.

Model a safe withdrawal rate and see how long a pot lasts against inflation and returns.

Build a valid robots.txt file with sitemap references and crawler rules.

Calculate return on investment and the annualised rate.

Convert numbers to roman numerals and roman numerals back to numbers, from 1 to 3999.

Shift letters by any amount — ROT13, ROT47 and every rotation in between, with a full table.

Calculate your pace per kilometre or mile and project finish times for common races.

Convert between hourly, daily, weekly, monthly and annual pay.

Generate realistic REST, JSON:API, GraphQL and error-envelope responses with pagination.

Download ready-made sample datasets — users, orders, products, transactions — as CSV, JSON, SQL or Excel-ready TSV.

Turn a JSON Schema into realistic sample documents, respecting types, enums, formats and constraints.

Generate realistic Apache, Nginx, JSON, syslog or application logs with a controllable error rate.

Generate Markdown documents exercising every feature — tables, code, footnotes, task lists and more.

Generate complete fake personas — name, email, address, phone, job, company, bio and avatar.

Generate CREATE TABLE and INSERT statements with realistic seed data for four SQL dialects.

Work out how long it takes to reach a savings target, and what to save monthly.

Generate JSON-LD structured data for organisations, articles, FAQs, products and more.

Convert between standard decimal numbers and scientific or engineering notation.

Draw gift assignments where nobody gets themselves, with exclusions for couples.

Test versions against a range, sort by precedence, or compare two releases.

Break a paragraph into one sentence per line, handling abbreviations and decimals correctly.

Preview how your page title and description will appear in Google search results.

Convert shoe size between 7 units with the formula, a reverse conversion and a quick-reference table.

Calculate simple interest and see how it differs from compound interest.

Project a monthly investment plan, with optional annual step-up and the invested-versus-gain split.

Turn a list of URLs into a valid XML sitemap ready to submit to search engines.

Find the best times to sleep or wake based on 90-minute sleep cycles.

Turn any title into a clean, SEO-friendly URL slug with accents stripped and symbols removed.

Count characters against the limits for X, Instagram, LinkedIn, Bluesky and more.

Convert speed between 7 units with the formula, a reverse conversion and a quick-reference table.

Format and indent SQL queries for MySQL, PostgreSQL, SQLite, SQL Server and BigQuery.

Turn a pasted column of values into a safely quoted SQL IN clause, batched if needed.

Calculate mean, median, mode, range, variance and standard deviation from a list of numbers.

Measure text in UTF-8, UTF-16 and UTF-32 bytes, code points and grapheme clusters.

Escape strings for JSON, JavaScript, CSV, SQL, XML or shell — and unescape them again.

Convert between SRT, WebVTT, ASS/SSA, MicroDVD and plain text.

Join two subtitle files end to end, or stack two languages into bilingual cues.

Check subtitles against broadcast standards for reading speed, line length and duration.

Fix out-of-sync subtitles by shifting every cue, or stretching them for a frame-rate change.

Calculate sunrise, sunset, twilight and day length for any latitude and longitude.

Turn CSV, TSV or pasted spreadsheet data into a Markdown, HTML or reStructuredText table.

Convert indentation between tabs and spaces without disturbing alignment inside lines.

Generate a full 50–950 Tailwind colour scale from a single brand colour.

Convert temperature between 5 units with the formula, a reverse conversion and a quick-reference table.

Watch sampling parameters change which tokens can actually be chosen, on a real softmax over logits you supply.

Generate Luhn-valid test card numbers for seven brands.

Strip smart quotes, invisible characters, ligatures and stray whitespace pasted from Word or a PDF.

Pad every line to a fixed width with any character, on the left, right or both sides.

Repeat any text a set number of times, separated by newlines, spaces or nothing.

Reverse text by character, word or line — useful for puzzles, testing and mirrored strings.

Design text shadows, outlines and glow effects with a live preview.

Randomly reorder lines, words, sentences or characters, with a seed for repeatable results.

Compare two texts with Levenshtein distance, Jaccard, cosine and Dice coefficients.

Count how often each word, character or line appears in your text.

Shorten text to a character, word or sentence limit without cutting words in half.

Hard-wrap text at a line width, or truncate it to a maximum length.

Convert time between 11 units with the formula, a reverse conversion and a quick-reference table.

Total daily clock-in and clock-out times, with breaks, rounding and optional pay.

Convert Unix timestamps to human dates and back, in seconds or milliseconds.

Convert a time between any two time zones, with daylight saving handled correctly.

Find the hours that are inside working time for everyone, across up to a dozen timezones.

Work out the tip and split a bill evenly between any number of people.

Apply AP, Chicago, APA or MLA title capitalisation rules — each treats small words differently.

Convert torque between 5 units with the formula, a reverse conversion and a quick-reference table.

Generate time-based one-time passwords from a Base32 secret to test 2FA setups.

Check whether a button or link meets the minimum tap target size and spacing.

Build a single-elimination bracket with byes placed correctly for any number of entrants.

Turn a plain transcript into timed SRT or WebVTT cues at a realistic reading speed.

Calculate sine, cosine, tangent and their inverses in degrees or radians.

Paste your meta tags to check the X card type, title, description and image against the documented rules, including Open Graph fallbacks.

Build a modular typographic scale and copy it as CSS custom properties.

Convert text between code points, UTF-8, UTF-16, HTML entities and escape sequences.

Convert characters to \u escape sequences and back — for JSON, JavaScript and source code.

Work out which pack size is actually cheaper per unit, weight or volume.

Flip text upside down using Unicode look-alike characters, readable when rotated 180°.

Compose a URL from its parts with correctly percent-encoded query parameters.

Percent-encode text for safe use in URLs, and decode encoded URLs back to readable text.

Break a URL into protocol, host, path, query parameters and fragment.

Break down a user-agent string into browser, engine, operating system and device.

Generate available-looking usernames and handles in several styles.

See exactly how text is encoded — code points, UTF-8 bytes, names and byte counts per character.

Build tagged campaign URLs that track correctly in Google Analytics.

Identify a UUID version and variant, and extract the timestamp from v1, v6 and v7.

Generate random RFC 4122 version 4 UUIDs in bulk.

Generate time-sortable UUID version 7 identifiers — ideal as database primary keys.

Validate emails, UUIDs, IP addresses, credit card numbers, IBANs and semver strings.

Add or remove VAT, GST or sales tax at any rate, with the net and tax split out.

Convert volume between 16 units with the formula, a reverse conversion and a quick-reference table.

Estimate how much water to drink each day based on weight, activity and climate.

Find the ISO 8601 week number, quarter and day of year for any date.

Convert weight between 12 units with the formula, a reverse conversion and a quick-reference table.

Calculate a weighted mean — for grades, ratings and portfolio returns.

Strip extra spaces, tabs, blank lines and trailing whitespace from any text.

Count words, characters, sentences and paragraphs, with reading time and readability.

Count how often each word appears, with stop-word filtering and a frequency chart.

Convert written English numbers back into digits — "two hundred and fifty" becomes 250.

Convert between words, characters, pages and tokens using measured ratios for prose, code, JSON and CJK.

Count business days between two dates, excluding weekends and your own holiday list.

Format messy XML with proper indentation, or minify it back down, with well-formedness checked.

Check XML is well-formed, with the exact line and column of the first error and a document summary.

Format and validate YAML — catch the indentation mistakes that break CI pipelines.

Get the thumbnail image URLs for any YouTube video, in every available size.

Paste your CSS and find the property that trapped the element in a stacking context.

Calculate how many standard deviations a value sits from the mean, with percentile.