Resistor Color Code
Decode 4, 5, or 6 band resistors and look up color bands from a resistance value.
4/5/6 band decodeReverse lookupColor reference
View detailsElectronics Tools
Free interactive calculators for makers, hobbyists, and engineers. Decode resistor bands, solve Ohm's law, design voltage dividers, combine resistors, read SMD codes, and configure 555 timers — no account required.
Browse electronicsOhm's Law Calculator
Enter any two of voltage, current, resistance, and power to calculate the rest.
VoltageCurrentPower
View detailsVoltage Divider
Solve for input voltage, output voltage, or resistor values in a no-load divider.
Divider mathUnit supportLoad current
View detailsSeries & Parallel Resistors
Add up to 10 resistors and calculate equivalent resistance in series or parallel.
SeriesParallelUp to 10 resistors
View detailsSMD Resistor Code
Decode 3-digit, 4-digit, and EIA-96 SMD markings — or find codes from a resistance value.
3-digit4-digitBidirectional
View details555 Timer Calculator
Calculate astable frequency, period, and duty cycle, or monostable pulse width from R and C.
AstableMonostableAll units
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