Electronics Calculators & Engineering Tools
Calculate resistor values, voltage dividers, battery life, power consumption, LED resistors, and more with our free electronics engineering tools.
Resistor Color Code
Instant 4, 5, and 6 band resistor color code decoder with tolerance & PPM support.
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Ohm's Law Calculator
Calculate Voltage (V), Current (I), Resistance (R), and Power (P) with interactive formulas.
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Voltage Divider
Calculate output voltage (Vout) for resistor divider networks instantly.
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Series Resistors
Compute the total equivalent resistance for multiple resistors connected in series.
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Parallel Resistors
Calculate the equivalent resistance (Req) of multiple resistors in parallel.
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LED Current Limiting
Calculate the exact current-limiting resistor required to safely drive your LEDs.
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Battery Runtime
Estimate battery discharge backup time in hours and minutes from load current & efficiency.
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