Calculators
Electronics calculators for makers
Eight fast, no-signup tools. Each one explains the formula, shows a worked example and gives you a link to share your exact numbers.
Resistor Color Code Calculator
Decode 4, 5 and 6-band resistors — or find the bands for any value.
Open calculatorLED Resistor Calculator
Find the current-limiting resistor for any LED and supply voltage.
Open calculatorVoltage Divider Calculator
Work out the output voltage of a two-resistor divider — with optional load.
Open calculatorBattery Life Calculator
Estimate runtime from battery mAh, sleep/active current and duty cycle.
Open calculatorOhm's Law Calculator
Fill in any two of voltage, current, resistance or power — get the rest.
Open calculator555 Timer Calculator
Frequency, duty cycle and pulse width for astable and monostable 555 circuits.
Open calculatorWire Gauge & Current Calculator
Pick the right AWG wire size: current rating, resistance and voltage drop.
Open calculatorRC Time Constant Calculator
Time constant, cutoff frequency and capacitor voltage over time.
Open calculator
Free download
The Microcontroller Cheat Sheet
Logic levels, pins to avoid, I2C / SPI / UART basics and a quick-pick table of the best boards — on one printable PDF. Enter your email and it's yours.
Only used to send the sheet and the odd databit.me update. See the privacy policy.