Is this calculation free and private?

Yes, 100% of calculations execute locally in your web browser. No inputs or personal data are stored or transmitted.

What does the Battery Backup Runtime & UPS Capacity Calculator give me?

It works out Total Battery Energy, Usable Energy, Estimated Runtime and Estimated Runtime, updating live as you change the inputs.

What do I need to enter?

Just Battery Capacity, Battery Bank Voltage, Continuous Load, Usable Depth of Discharge DoD and Inverter Efficiency. Every field has a sensible default you can start from.

Is my data uploaded anywhere?

No. The calculation runs in your browser with JavaScript — nothing you type is sent to a server or stored.

Does it work on a phone?

Yes. The layout adapts to small screens and needs no app or signup.

Battery Backup Runtime & UPS Capacity Calculator

Calculate emergency battery bank runtime in hours based on continuous load wattage, Ah rating, system voltage, and DoD.

100% free
Private in browser
No signup
No watermarks

Battery Capacity (Amp-Hours Ah)

Battery Bank Voltage (V)

Continuous Load (Watts)

Usable Depth of Discharge DoD (%)

Inverter Efficiency (%)

Total Battery Energy (Wh)

2,400

Usable Energy (Wh)

1,920

Estimated Runtime (Hours)

4.8

Estimated Runtime (Total Minutes)

290

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About Battery Backup Runtime & UPS Capacity Calculator

Calculate emergency battery bank runtime in hours based on continuous load wattage, Ah rating, system voltage, and DoD. Enter Battery Capacity, Battery Bank Voltage and Continuous Load and the tool works out Total Battery Energy, Usable Energy and Estimated Runtime straight away. Everything runs in your browser, so your data never leaves your device.

How to use Battery Backup Runtime & UPS Capacity Calculator

Enter Battery Capacity, Battery Bank Voltage and Continuous Load.
Adjust the remaining options (Usable Depth of Discharge DoD and Inverter Efficiency) to match your case.
Read Total Battery Energy, Usable Energy and Estimated Runtime in the results panel — copy or download what you need.

Key features

Shows Total Battery Energy (Wh)
Shows Usable Energy (Wh)
Shows Estimated Runtime (Hours)
5 adjustable inputs, results update as you type
No signup, no limits

Frequently asked questions

Is this calculation free and private?: Yes, 100% of calculations execute locally in your web browser. No inputs or personal data are stored or transmitted.
What does the Battery Backup Runtime & UPS Capacity Calculator give me?: It works out Total Battery Energy, Usable Energy, Estimated Runtime and Estimated Runtime, updating live as you change the inputs.
What do I need to enter?: Just Battery Capacity, Battery Bank Voltage, Continuous Load, Usable Depth of Discharge DoD and Inverter Efficiency. Every field has a sensible default you can start from.
Is my data uploaded anywhere?: No. The calculation runs in your browser with JavaScript — nothing you type is sent to a server or stored.
Does it work on a phone?: Yes. The layout adapts to small screens and needs no app or signup.

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