Run Capacitor µF (MFD) Test Calculator

Under load, a capacitor's current and voltage reveal its real capacitance.

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Formula

C (µF) = I × 10⁶ ÷ (2π × f × V)
At 60 Hz: µF = 2652 × A ÷ V

Example calculation

3.8 A at 380 V across the capacitor → 26.5 µF.

Practical HVAC use

Test dual-run capacitors without removing them, using safe procedures.

Common mistakes

Using line voltage instead of the voltage across the capacitor.
Not discharging capacitors before handling.

Related lessons

Capacitors

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Educational tool. Results are estimates from the stated formulas; always confirm with manufacturer data and the code adopted in your jurisdiction. All calculators