Electronics Calculators

Resistor codes, capacitor codes, Ohm's Law, KVA/MOCP, battery life. All in one place, all in the browser.

Resistor Colour Code

4-band and 5-band

Band 1

Band 2

Band 3

Multiplier

Tolerance

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Capacitor Code Decoder

3-digit ceramic / film codes

Code (e.g. 104) 3 digits, optional letter suffix (J K M)

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KVA & MOCP Calculator

Apparent power & overcurrent protection

Phase

Voltage (V)

Current — FLA (A)

Power Factor Optional — 0.1 to 1.0

KVA

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kW (if PF given)

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Min MOCP

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Next Standard Breaker

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MOCP = FLA × 125% per NEC. Standard breaker sizes per UL 489.

Ohm's Law Solver

Enter any two — get all four

Voltage — V (volts)

Current — I (amps)

Resistance — R (ohms)

Power — P (watts)

Voltage (V)

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Current (A)

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Resistance (Ω)

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Power (W)

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Battery Life Estimator

mAh ÷ load current

Battery Capacity (mAh)

Load Current (mA)

Efficiency (%) Typical: 70–85%. Accounts for real-world loss.

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