Electronics Calculators
Quick, accurate math for the things you build — resistors, power budgets, MCU peripherals, and IoT link planning. No sign-up, runs entirely in your browser.
Electronics
Electronics
Core component math — resistors, capacitors, power, and battery life.
LED Resistor Calculator
Find the right current-limiting resistor for any LED, voltage source, and target brightness.
Voltage Divider Calculator
Calculate output voltage or resistor values for a two-resistor voltage divider network.
Ohm's Law Calculator
Solve for voltage, current, or resistance — enter any two values to find the third.
Power Calculator
Calculate electrical power from voltage and current, or solve for the missing variable.
Battery Life Calculator
Estimate how long a battery will last based on capacity and load current draw.
Pull-up Resistor Calculator
Choose a safe pull-up (or pull-down) resistor value for digital inputs and open-drain lines.
RC Time Constant Calculator
Calculate the time constant (τ = RC) and charge/discharge timing of an RC circuit.
Capacitor Calculator
Calculate series/parallel capacitance, energy stored, and reactance for a given capacitor.
Inductor Calculator
Calculate series/parallel inductance and inductive reactance for coils and chokes.
Resistor Color Code Calculator
Decode 4, 5, or 6-band resistor color codes into resistance, tolerance, and value — or go the other way.
MCUs
Microcontrollers
ESP32, Arduino & MCU peripheral math — PWM, ADC, UART, I2C.
ESP32 Flash Size Calculator
Plan ESP32 partition table sizing — app, OTA, SPIFFS/LittleFS, and NVS across common flash sizes.
PWM Duty Cycle Calculator
Convert between duty cycle %, on-time, frequency, and period for PWM signals.
ADC Resolution Calculator
Calculate ADC step size, resolution in volts, and the digital value for a given analog input.
UART Baud Rate Calculator
Calculate UART baud rate error from clock speed and divisor, or find the best divisor for a target baud rate.
I2C Pull-up Calculator
Calculate the correct I2C bus pull-up resistor range based on bus capacitance and speed mode.
IoT & RF
IoT & RF
Wireless range, LoRa airtime, MQTT payloads, and battery runtime.
Wi-Fi Range Estimator
Estimate Wi-Fi signal range using free-space path loss from transmit power, frequency, and receiver sensitivity.
LoRa Airtime Calculator
Calculate LoRa packet time-on-air from spreading factor, bandwidth, coding rate, and payload size.
MQTT Payload Size Calculator
Estimate total MQTT packet size including fixed header, variable header, topic, and payload overhead.
IoT Battery Runtime Calculator
Estimate battery runtime for IoT devices that alternate between deep-sleep and active transmit current.
Utilities
Utilities
Quick converters every maker reaches for — units, bases, ASCII, data size.
Electronics Unit Converter
Convert between common electronics units — ohms/kΩ/MΩ, farads, henries, hertz, and metric prefixes.
Binary ↔ Decimal ↔ Hex Converter
Convert instantly between binary, decimal, hexadecimal, and octal number systems.
ASCII Converter
Convert text to ASCII/hex/binary codes and back — handy for serial protocol debugging.
Data Size Converter
Convert between bits, bytes, KB, MB, and GB — and estimate transfer time at a given bitrate.
Wire Gauge (AWG) Calculator
Find wire diameter, resistance per length, and max current capacity for any AWG wire gauge.
555 Timer Calculator
Calculate output frequency, period, and duty cycle for 555 timer astable and monostable circuits.