🔌Hardware & Maker
Electronics calculators and pinouts for makers: resistors, voltages, timers, microcontrollers and more – free in your browser.
36 free tools – right in your browser, no sign-up.
Resistor Color Code Calculator
Decode 4- and 5-band color codes and calculate resistance value
Byte Converter
Convert between Bit, Byte, KB, KiB, MB, MiB, GB, GiB ...
LED Resistor Calculator
Calculate LED series resistor – ohms & power dissipation
Baud Rate Calculator
Divider, actual baud rate & error for microcontrollers
Voltage Divider Calculator
Calculate output voltage or resistor values for voltage dividers
NE555 Calculator
Calculate frequency, duty cycle and resistors for NE555 circuits
Capacitor Code Calculator
3-digit SMD/ceramic code ↔ capacitance (pF/nF/µF)
I²C Addresses
7-bit I²C addresses of common components and write address calculation
Raspberry Pi Pinout
BCM/WiringPi/Board numbering for all 40-pin GPIO models
Arduino Uno Pinout
ATmega328P · 14 Digital · 6 Analog · 6 PWM · UART / SPI / I²C
Arduino Nano Pinout
ATmega328P · 22 Digital (incl. A0–A5) · 8 Analog · 6 PWM · A6/A7 analog only
Teensy 4.1 Pinout
ARM Cortex-M7 · 600 MHz · 55 Digital · 18 Analog · CAN · USB Host
Raspberry Pi Pico Pinout
RP2040 · Dual-Core ARM Cortex-M0+ · 133 MHz · 3.3V · 26 Multi-Func GPIO
ESP32 DevKit v1 Pinout
Xtensa LX6 Dual-Core · 240 MHz · 3.3V I/O · 34 GPIO · ADC/DAC/Touch · WiFi + Bluetooth
ESP8266 NodeMCU v3 Pinout
Tensilica L106 · 80/160 MHz · 3.3V I/O · 11 usable GPIO · 1x ADC · WiFi 802.11 b/g/n
Modbus Parser
Create Modbus RTU frames, check CRC-16 and decode request/response fields
MQTT Explorer
Connect to MQTT broker via WebSocket, subscribe to topics and send messages
BACnet Explorer
Explore BACnet/IP devices and objects on the local network – requires socket-bridge
Gamepad Tester
Test controller buttons, triggers and axes in real time
Solar System Simulator
Annual simulation: generation, storage, grid feed-in and self-sufficiency calculation
Cable Cross-Section Calculator
Calculate wire cross-section and voltage drop (AWG/mm²) – ampacity per IEC 60364 incl. temperature effects
Battery Life Calculator
Calculate battery runtime from capacity and load – lead-acid, Li-ion, LiFePO4 with Peukert effect, reserve and temperature
Ohm's Law Calculator
Calculate voltage, current, resistance and power – enter two values, the other two are calculated
SMD Resistor Calculator
Decode and generate SMD resistor codes – 3/4-digit codes, R notation and EIA-96
Antenna Length Calculator
Calculate antenna lengths from frequency: half-wave dipole, quarter-wave ground plane, 5/8-λ and full-wave loop
LM317 Calculator
Calculate output voltage and resistor values for LM317 voltage regulator
Op-Amp Calculator
Calculate gain and resistor values for operational amplifier circuits
Transistor Bias Calculator
Calculate the operating point for voltage divider bias
PWM Calculator
Calculate prescaler, TOP and compare registers for timers
PCB Trace Width Calculator
Calculate minimum copper trace width per IPC-2221
Microphone Test
Test your microphone right in the browser: level meter, live waveform and a test recording – no upload.
Webcam Test
Test your webcam right in the browser: live preview, resolution, frame rate and snapshot – no upload.
Keyboard Tester
Test your keyboard online: see pressed keys live, check rollover, find dead keys.
Mouse Tester
Test your mouse online: all buttons including side buttons, double-click interval, scroll wheel and move rate.
Speaker Test
Test speakers and headphones: sine tone, left/right channel check and a 20 Hz to 16 kHz frequency sweep.
Monitor Test
Test your monitor online: full-color fields for dead pixels, gradient, color banding and grid pattern – fullscreen.