Free Solar & Off-Grid Tool · 2026

Inverter Sizing Calculator

Add your AC loads with surge factors to get continuous and peak VA, inverter type recommendation, battery current draw, fuse rating and wiring gauge.

AC Load Profile
Continuous load
0 W
Peak surge load
0 W
System Settings
Waveform Requirement
Pure Sine Wave
Required for motors, compressors, medical equipment, sensitive electronics, and grid-tie systems
Modified Sine Wave
Suitable for resistive loads, basic lighting, phone chargers — lower cost but not universal
Results
Recommended Inverter Size
—VA
Add loads and click Size My Inverter
Continuous Power
—W
Peak / Surge
—W
DC Input Current
—A
Surge DC Current
—A
Recommended Fuse
—A
DC Cable (AWG)
—

Surge/startup factors are typical industry values — verify with manufacturer datasheets for critical loads.
VA = W ÷ Power Factor. Always size inverter to handle peak surge, not just continuous load.
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