Fast engineering tools for component selection, tolerance analysis, worst-case calculations, and everyday circuit design.
Voltage DividerSelect standard resistor values and compare alternatives, with worst-case output voltage, loading effects, and resistor power guidance.
Parallel ResistorCalculate combined resistance, find standard resistor combinations, and evaluate tolerance, current, and power.
LED Series Resistor CalculatorChoose a standard resistor for one or more LEDs, calculate current from a known resistor, and check current limits and resistor power.
Multi-Tap Voltage DividerDesign 2- and 3-tap resistor ladders for window comparators and multiple voltage thresholds. Find standard resistor combinations and check worst-case tolerance and power.
Resistor Color CodeConvert resistor color bands to values—or values back to color bands.
SMD Resistor CodeDecode and generate 3-digit, 4-digit, and EIA-96 resistor markings.
SMD Capacitor CodeDecode and generate capacitor markings, with tolerance and EIA-198 support.More engineering tools coming soon
Choose practical standard E-series values with the Voltage Divider Calculator. Design 2-tap and 3-tap ladders with the Multi-Tap Voltage Divider Calculator, or combine 2–10 resistors with the Parallel Resistor Calculator. Use the LED Series Resistor Calculator to choose a series resistor for one or more LEDs, or check the current through a resistor you already have.
Evaluate worst-case tolerance and resistor power with the Voltage Divider, Multi-Tap Voltage Divider, Parallel Resistor, and LED Series Resistor calculators. Their wattage recommendations account for utilization margin and temperature derating. Check divider loading, multi-tap threshold and window limits, continuous and pulsed parallel-resistor operation, or the LED current range produced by supply-voltage and component limits.
Read component markings or work backward from a value to the corresponding code. Use the Resistor Color Code Calculator, SMD Resistor Code Calculator, and SMD Capacitor Code Calculator to check supported markings and values.
Each calculator explains its methods, assumptions, and results so you can assess how they apply to your design. Where supported, results include tolerance ranges and worst-case values alongside nominal calculations. Check the selected component’s datasheet for specifications and operating limits that the calculator does not model.
