Watt and Ampere Calculator
Inverter DC Current Tool

Inverter Watts to Amps Calculator

Find how many amps an inverter draws from the battery bank for a given AC load. Inverter efficiency (typically 85-92%) increases the DC input current beyond a simple watts/volts calculation. Use this to size DC fuses, cables, and battery capacity.

Conversion direction
Electrical system
Quick voltage presets
Calculated result1000 W · 120 V · DC
8.333 A
Formula usedI = P / V

Custom voltage is always supported.

Formulas Used

DCI = P / V

No power factor needed for DC circuits.

AC 1φI = P / (V × PF)

Single-phase AC — multiply voltage by power factor.

AC 3φI = P / (√3 × V × PF)

Three-phase AC — divide by √3 ≈ 1.732.

Frequently Asked Questions

How many amps does a 2000W inverter draw from a 12V battery?

At 90% efficiency: DC amps = 2000 / (12 x 0.90) = 185.2 A. This is why 12V inverters above 2000W require very heavy cables (2/0 AWG or larger).

Why does efficiency matter for inverter current calculations?

Inverters convert DC to AC with some power loss. A 90% efficient inverter delivering 2000W AC actually draws 2000 / 0.90 = 2222W from the battery. Use the correct DC current for cable and fuse sizing.