calc.engineer

Calculate free-space path loss (FSPL) in decibels using the ITU-R P.

Compute a full RF link budget from transmitter power, frequency, distance, and antenna gains.

Calculate physical dimensions of a dipole antenna for a given frequency.

Calculate PCB microstrip trace width for a target characteristic impedance using the Hammerstad-Jensen closed-form equations.

Convert a power level in dBm to milliwatts, watts, dBW, and RMS voltage across a given impedance.

Calculate the cascaded noise figure of a multi-stage receiver chain using the Friis formula.

Convert between VSWR, return loss, and reflection coefficient — provide any one parameter and get all related impedance-mismatch metrics.

Design a Pi-topology resistive attenuator pad.

Design a Tee-topology resistive attenuator pad.

Calculate the Fresnel zone radius at the midpoint of a radio link.

Convert between radio frequency and wavelength.

Generate a complete SPICE netlist from a parameterized template.

Run a SPICE circuit simulation directly in the worker.

Calculates LoRa packet time-on-air using the Semtech AN1200.

Computes LoRa link SNR margin by comparing received power against the noise floor and the spreading-factor-dependent demodulation threshold from the Semtech SX1276 datasheet.

Estimates Meshtastic or LoRa mesh channel utilization percentage based on node count, message rate, and per-packet airtime.

Estimates LoRa maximum communication range by computing the free-space path loss (FSPL) link budget and applying terrain-dependent correction factors.

Calculates LoRa receiver sensitivity from spreading factor, bandwidth, and noise figure using the Semtech SX1276 datasheet SNR thresholds.

Calculates LoRa duty cycle budget for EU868, US915, AS923, and AU915 regulatory regions.

Estimates Meshtastic node communication range using real hardware profiles and firmware channel presets.

Checks EIRP (Effective Isotropic Radiated Power) compliance against regional regulatory limits for LoRa and Meshtastic operation.

Calculates Meshtastic node power consumption and battery runtime using device-specific power profiles and firmware role-based duty cycling.

Recommends optimal LoRa spreading factor, bandwidth, and TX power based on target range, terrain, and optimization priority.

Calculate usable ZFS pool capacity for any RAID level including stripe, mirror, raidz1, raidz2, and raidz3.

Calculate recommended RAM and ARC sizing for a ZFS storage pool based on workload type, pool size, deduplication status, and L2ARC cache size.

Calculate maximum TCP throughput using the Bandwidth-Delay Product (BDP) formula.

Calculate the optimal MTU for a WireGuard VPN tunnel interface with a detailed overhead breakdown.

Calculate IPv4 subnet details from CIDR notation.

Estimate RAID array IOPS performance and latency for ZFS and traditional RAID configurations.

Calculate total power consumption, electricity cost, and circuit requirements for a homelab.

Estimate the cooling load (BTU/hr) for a homelab or server closet based on equipment wattage, room dimensions, insulation quality, and solar exposure.

Quick rack space and weight sizing calculator for homelab and small data center racks.

Plan and validate network link capacity for homelab workloads.

Estimate steady-state thermal behaviour of a rectangular enclosure (server rack, electronics housing, equipment cabinet) using a lumped-parameter energy balance with natural-convection and radiation correlations, or forced-flow air energy balance.

Analyze a forced-convection fin-array heatsink using established channel-flow correlations (developing laminar Nusselt, fin efficiency tanh(mH)/mH, parallel-plate friction).

Estimate PCB component temperatures by solving a thermal resistance network (thermal↔electrical analogy) with the built-in MNA solver.

Calculates battery runtime and energy capacity given cell capacity in mAh, nominal voltage, and average current draw.

Determines the minimum AWG (American Wire Gauge) conductor size for a given current, voltage, one-way cable distance, and maximum allowable voltage drop percentage.

Sizes an off-grid solar power system by calculating the number of panels and battery bank capacity required for a given daily energy consumption.

Estimates UPS (Uninterruptible Power Supply) backup runtime from battery specifications and connected load.

Converts battery capacity from milliamp-hours (mAh) to watt-hours (Wh), kilowatt-hours (kWh), and joules (J) given the nominal cell voltage.

Converts electrical power in watts to current in amps (and milliamps) for a given voltage, using the DC power formula P = V * I.

Calculates voltage drop across a conductor run given current, wire length, AWG gauge, system voltage, and conductor material (copper or aluminum).

Estimates battery charge time given capacity in mAh, charge current in mA, charger efficiency, and initial state of charge.

Calculates total daily energy consumption from an appliance list — the critical first step before sizing solar panels or batteries.

Calculates solar system return on investment, payback period, and levelized cost of energy (LCOE).

Calculates how many days a battery bank can sustain loads without solar input — critical for off-grid and backup power sizing.

Calculates optimal solar panel string and MPPT configuration based on panel electrical specs, inverter/charge-controller MPPT limits, and site temperature extremes.

Compares total cost of ownership between a fuel generator and a solar+battery system over a configurable time horizon.

Determine minimum wire gauge using NEC Table 310.

Size a DC-to-AC inverter for off-grid solar, battery backup, or mobile power systems.

Turn a SPICE netlist into a fab-ready 2-layer PCB: assigns real footprints (0805, TO-92, DO-35, DIP-8, headers, LED, radial-cap), auto-places components (connectivity-aware; or use your own placement), routes a 2-layer maze router with vias, and VERIFIES the result with DRC (clearance/crossing checks) and ERC (union-find copper connectivity proven against the netlist).

Calculates output voltage, current draw, and power dissipation for a resistive voltage divider.

Computes the cutoff frequency, time constant, impedance, and phase shift of a first-order RC filter.

Calculates the resonant frequency of an LC circuit, along with optional Q factor and bandwidth when series resistance is provided.

Designs an L-network impedance matching circuit between two real impedances at a given frequency.

Calculates the minimum PCB trace width for a given current using the IPC-2221 standard formula.

Solves Ohm's Law and the power equation given any two of four electrical quantities: voltage (V), current (I), resistance (R), and power (P).

Decodes 4-band or 5-band resistor color codes into resistance value, tolerance, and min/max range.

Calculates the current-limiting resistor for driving one or more LEDs in series from a DC supply.

Calculates timing parameters for the ubiquitous NE555 / LM555 timer IC in astable (free-running oscillator) and monostable (one-shot pulse) modes.

Calculate voltage gain and output for operational amplifier circuits in inverting, non-inverting, and differential configurations.

Calculates RC capacitor charge timing, energy storage, and transient voltages.

Calculate PCB via current-carrying capacity using the IPC-2221 standard.

Select bypass and bulk decoupling capacitors for IC power supply pins.

Compute logarithms of a positive number in any base.

Count significant figures in a number and optionally round to N significant figures.

Convert any number to scientific notation and engineering notation.

Calculate what percentage one number is of another.

Calculate the percentage change between an old value and a new value.

Compute the result of raising a base to an exponent (base^exponent).

Compute the square root of a non-negative number.

Calculate the circumference and area of a circle given either a radius or diameter.

Calculate the slope, y-intercept, line equation, angle, and distance between two points in a 2D Cartesian plane.

Solve for any side of a right triangle using the Pythagorean theorem (a² + b² = c²).

Calculate the p-value for a z-score or t-statistic.

Calculate the confidence interval for a sample mean.

Calculates total cost including sales tax for a purchase.

Converts compensation between annual salary, monthly pay, weekly pay, and hourly wage.

Computes a full loan amortization schedule given principal, annual interest rate, and term in months.

Calculates compound interest growth over time using the formula A = P(1 + r/n)^(nt).

Calculates a test or exam grade from the number of correct answers and total questions.

Calculates area and perimeter for common shapes — rectangle, circle, or triangle — in both imperial and metric units.

Convert between units across 10 categories: length (m, km, mi, ft, in, yd, nmi), mass (kg, lb, oz, g, ton), volume (l, gal, ml, cup, fl_oz), area (m2, ft2, acre, hectare), speed (mps, kph, mph, knot), pressure (pa, psi, bar, atm, mmhg), energy (j, kwh, btu, cal, wh), data (b, kb, mb, gb, tb), time (s, ms, min, hr, day, year), and temperature (c, f, k).

Convert numbers between hexadecimal, binary, decimal, and octal bases.

Convert between Unix timestamps and human-readable date/time formats.

Calculate Body Mass Index (BMI) from weight and height using the WHO standard formula.

Calculate tip and split a restaurant bill among multiple people.

Calculate the difference between two dates in days, weeks, months, years, and business days.