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Inverter Peak Load & Surge Calculator

Continuous load

2,100W

3 motor loads running · 15% headroom in recommendation

Peak surge requirement

7,688W

Staggered start · saves 1,762 W vs. all motors at once (9,450 W)

Recommended inverter

5,000W

Your recommended inverter comes out to about 5,000 W. In everyday terms, that's about 3.3× a microwave's draw.

5000 W cont · 10000 W surge class · 3 loads

How this calculator works

How to use the Inverter Peak Load & Surge Calculator

The Formula

Continuous watts are the sum of running loads. Peak watts add the largest motor surge margin (running × (factor − 1)) plus 35% of the second-largest—modeling staggered starts instead of every motor at once.

Practical Example

We snap to standard pure-sine tiers with ~2× surge rating and 15% continuous headroom. Verify manufacturer surge seconds and LRA on motor nameplates.

About Inverter Peak Load & Surge Calculator

Continuous vs. peak

Continuous watts are the sum of running loads. Peak watts add the largest motor surge margin (running × (factor − 1)) plus 35% of the second-largest—modeling staggered starts instead of every motor at once.

Picking an inverter

We snap to standard pure-sine tiers with ~2× surge rating and 15% continuous headroom. Verify manufacturer surge seconds and LRA on motor nameplates.

Frequently asked questions

Q: All motors start together? A: Use naive sum (set one load with combined watts) or add a higher surge factor. Q: vs. AC inrush tool? A: That sizes breakers in amps; this sizes inverters in watts. Q: Battery bank? A: Pair with Home Backup Sizing after you know AC load.