Fast, accurate calculators for electronics and software engineering. No ads in your face, results as you type, shareable links.
Convert between binary, octal, decimal, hex — or ASCII text — with every base shown at once, correct at any size.
Type full expressions like (0xFF << 2) | 0b1010 — see the result in hex, decimal, octal, and binary at once.
Decimal ↔ hex ↔ bits for float32 and float64, with sign/exponent/mantissa split out and the rounding error shown.
Exact fractions, best simple approximations, and nearest machinist fractions (16ths to 64ths) — in both directions.
Pick band colors to read a resistor, or type a value to get its bands — 4, 5, and 6-band codes, both directions.
Decode a chip-resistor marking (472, 4702, 4R7, 01C) into ohms — or get the marking for a value. Both directions.
Type a code like 104 or 4R7 to get the capacitance — or a capacitance to get the code — tolerance letters included.
Type a value in any unit — pF, nF, µF, mF, or F — and every other unit updates instantly.
Enter any two values — voltage, current, resistance, or power — and the other two are calculated instantly.
Output voltage, current, and power for any two resistors — or work backward to the best standard resistor pair for a target.
Add as many resistors as you like, see the schematic and totals live — or work backward from a target resistance.
Add capacitors in series or parallel and see the total and schematic live — the mirror image of resistor math.
Pick your supply, LED, and current — get the exact resistor, the nearest standard value, and the power rating you need.
Enter any two of R, C, and cutoff frequency — get the third, the time constant τ, and the charge/discharge curve.
Frequency, period, and duty for astable; pulse width for monostable — with a solver that picks resistors for a target.
Inductive and capacitive reactance and LC resonance — enter any two values in each block, get the third.
Gain from your resistors, or the best standard resistor pair for a target gain — inverting and non-inverting.
LM317 resistor pairs for any output voltage — with real E-series suggestions — plus a zener shunt regulator designer.
IPC-2221 trace width for a current and temperature rise — or the current a width can carry — plus resistance and drop.
Find the minimum wire gauge for your voltage, current, and run length — sized by voltage drop, for copper or aluminum.
Enter your wire gauge, current, and run length — get the voltage drop, the voltage at the load, and power lost in the cable.
Estimate runtime from capacity and load — with a duty-cycle mode for sleep/active devices and honest derating.
Convert power and amplitude ratios to and from dB, and watts to and from dBm — each field works both ways.
Enter attenuation and impedance — get exact Pi and T pad resistors, plus the nearest standard values and what they actually deliver.
Enter any one of RMS, peak, peak-to-peak, or average — get the others, for sine, square, and triangle waveforms.
Dipole, quarter-wave, and other antenna lengths from a frequency — metric and imperial, with a shortening factor and band presets.
Single-layer air-core coils by Wheeler's formula: get inductance from a winding, or the turns to hit a target — plus wire needed.
CRC-8 through CRC-64 with the standard presets — plus simple checksums — computed locally; your data never leaves the page.
MD5, SHA-1, SHA-256, and SHA-512 of any text — computed locally in your browser, never uploaded.
Entropy and realistic crack times for randomly generated passwords and diceware passphrases — with the assumptions stated, not invented.
Text, Base64, hex bytes, and URL-encoding in one view — edit any pane and the rest follow, with correct UTF-8 handling.
Header, claims, expiry, and HS256 signature verification — all local, so your token never leaves the page.
Pretty-print, minify, and validate JSON locally — with the exact line and column of the first error.
Octal, symbolic, and checkboxes — edit any one and the others follow, including setuid/setgid/sticky.
Optimal bits and hash functions for your element count and false-positive target — or the real false-positive rate of an existing filter.
Paste two texts and see every changed line — with the changed words highlighted inside them. Nothing is uploaded.
Paste two JSON documents and see exactly what changed — structurally, not line by line, and never uploaded.
Paste two YAML files and see what actually changed — structure-aware, type-aware, and never uploaded.
Paste two XML documents and see element-level differences — attribute order ignored, nothing uploaded.
Pick a key column and see added, removed, and changed rows — with the changed cells highlighted. Nothing is uploaded.
L = λW: solve any one of concurrency, arrival rate, and time in system — plus M/M/1 utilization, queue length, and wait times.
How many agents — or threads, or connections — you need: offered load, wait probability, service level, and pool sizing from queueing math.
Usable space, fault tolerance, and rebuild risk for RAID 0, 1, 5, 6, and 10 — with mixed drive sizes and honest URE math.
Call and put fair value, delta, gamma, vega, theta, rho — and implied volatility backed out from a market price.
The bankroll fraction that maximizes long-run growth — full Kelly, fractional Kelly, and what overbetting costs you.
Nominal to effective annual rate and back, for any compounding frequency including continuous.
Units and revenue to break even — and the margin-vs-markup converter that settles pricing arguments.
From daily watt-hours to array watts, battery bank size, and inverter rating — honest off-grid sizing with derating explained.
How long a charge takes and what it costs — from battery size, charge window, charger power, and your electricity rate.
sP × sS to pack voltage, capacity, energy, and max current — with cell presets for 18650, 21700, and LiFePO4 builds.
File size ÷ link speed, done right — decimal vs binary units handled correctly, with presets for common interfaces.
Convert frequency ↔ period instantly, with wavelength, angular frequency, and clock-cycle timing thrown in.
Timestamp to date and date to timestamp — seconds or milliseconds, local and UTC side by side.
The time between two dates in years/months/days, total days, and weekdays — or add and subtract days from a date.
Every calculator on this site follows the same rules: results update as you
type, values accept engineering prefixes like 4.7k and
100n, every result has a copy button, and the address bar always
holds a link you can share that reproduces your exact calculation. Nothing is
sent to a server — all math runs in your browser, instantly.