Skip to content

Calculators

Authors:

Geoffrey Hunter

Geoffrey Hunter

Published On:

May 23, 2026

Last Updated:

May 23, 2026

Every calculator on this site lives next to the topic page that introduces the concept it computes. Use the search box to filter, then click any card to open the calculator in context.

28 of 28

BLE advertising packet decoder/builder

Paste a raw BLE advertising payload as hex to see its AD structures broken out, or build a payload from the structure editor and watch the hex update in real time.

Boost converter

Generic boost-converter design helper (CCM): from V_in, V_out, diode/switch drops, switching frequency, output current and ripple, compute the duty cycle, average and peak inductor current, and required inductance.

Generic buck-converter design helper: from V_in, V_out, diode/switch drops, switching frequency, output current and ripple, compute the duty cycle and required inductance.

Capacitor charge (Q = CV)

Solve for any one of charge, capacitance or voltage in the fundamental capacitor equation Q = CV, given the other two.

Compute the CRC of arbitrary data (text or hex) against any of 40 pre-defined CRC algorithms — from CRC-3/ROHC through CRC-64. Shows the algorithm parameters so you can verify what you're actually computing.

Dew point (Magnus)

Solve the August-Roche-Magnus equation for air temperature, relative humidity or dew point given the other two. Useful when working with humidity sensors that report temperature and RH.

E-series resistor finder

Find the closest E6 / E12 / E24 / E48 / E96 / E192 preferred value to a desired resistance, with percentage error and closest equal-or-higher / equal-or-lower values for each series.

EIRP compliance world map

Enter your transmitter power, antenna gain and band; a world map colours each country green or red based on whether your EIRP is within that jurisdiction's regulatory limit.

RF power unit converter

Convert freely between W, mW, µW, dBm and dBW. Edit any field and the rest update live.

LED current-limiting resistor

Calculate the series resistor needed to current-limit an LED, plus the power the resistor will dissipate. Pick a colour for typical V_F values or enter your own.

Low-pass RC filter

Solve f_c = 1/(2πRC) for any one of resistance, capacitance or cutoff frequency in a first-order passive low-pass RC filter.

Microstrip impedance

Compute the characteristic impedance of a microstrip PCB track from its width, copper thickness, substrate height and substrate dielectric constant using the rfcafe approximation.

Moving average filter designer

Interactive simple moving average (SMA) filter designer. Adjust the window size and sampling frequency to see the input/output signals and the resulting magnitude frequency response.

MP4558 design tool

Calculate the passive component values, switching-frequency resistor, inductor, peak inductor current and input/output ripple voltages for a buck converter built around the Monolithic Power MP4558 IC.

Beta-equation solver for an NTC thermistor. Pick any one of β, reference resistance R₀, reference temperature T₀, measured resistance R, or measured temperature T to compute from the other four.

Ohm's law (V = IR)

The hammer in every electrical engineer's toolbox. Solve for any one of voltage, current or resistance given the other two.

Capacitors in parallel

Compute the total capacitance of two or more capacitors in parallel (C_total = ΣC_i).

Resistors in parallel

Compute the equivalent resistance of two or more resistors in parallel. Accepts metric prefixes (e.g. 10k, 2M2, 470R).

Resistor divider

Solve for any one of V_IN, V_OUT, R1 or R2 in a two-resistor voltage divider, given the other three.

Convert a 3D rotation between angle-axis, quaternion, rotation matrix, and intrinsic Euler angles (XYZ, XZY, YXZ, YZX, ZXY, ZYX). Useful for sanity-checking how a rotation is represented across libraries.

Capacitors in series

Compute the total capacitance of two or more capacitors in series (1 / C_total = Σ 1/C_i).

Resistors in series

Compute the equivalent resistance of two or more resistors in series.

555 timer (astable)

Calculate the two timing resistors (R1, R2) and on/off times needed to run a 555 in astable mode at a given output frequency, duty cycle and timing capacitor.

Track current (IPC-2152)

PCB track current carrying capability calculator using the IPC-2152 standard — more accurate than IPC-2221A but requires board thickness, plane proximity and substrate thermal conductivity.

Track current (IPC-2221A)

PCB track current carrying capability calculator using the older IPC-2221A standard. Simpler than IPC-2152 — needs only track thickness, temperature rise, and whether the track is external or internal.

Via current (IPC-2221A)

Maximum current (ampacity), cross-sectional area, electrical and thermal resistance of a PCB via, using the IPC-2221A standard applied to the via's plated annulus.

Via thermal resistance

Top-to-bottom thermal resistance of a PCB via modelled as a hollow copper cylinder. Inputs: via diameter, plating thickness, via height, and copper thermal conductivity.

Find the minimum AWG gauge wire needed to carry a given DC current with no more than a specified voltage drop across the cable length. Picks the conductor resistivity from a material table or accepts a custom value.