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Plan your backup power · Free calculator

Inverter and Battery Combined Planner

Use this free calculator to plan inverter capacity and battery ah in one joined workflow. Change the load, starting surge, losses and battery limits to match your equipment.

Updated 16 July 2026Use for planningFormula and steps shown

Enter your details

Your values

Every input includes a simple explanation.

Running backup loadThe combined watts used after all connected appliances are running normally.

Peak load as % of runningThe short starting power as a percentage of the normal running load.

Power factorHow effectively the electrical load uses supplied power. Use the equipment value when known.

0–1

Safety marginExtra capacity kept above the calculated need so the system is not fully stretched.

Desired backupHow many hours the appliance runs, or how many backup hours you want.

hours

Battery voltageThe voltage printed on the battery or the total connected battery bank.

Depth of dischargeThe percentage of stored battery energy you plan to use before recharging.

Inverter efficiencyThe percentage of input energy that reaches the useful output after losses.

Private: the calculation runs in your browser. Your inputs are not sent to GharGanit.

Get a useful answer

How to use this calculator

Use a real value. Check an appliance label, bill, site measurement, product sheet or official record.
Replace the examples. Example values show how the tool works; they do not describe every home.
Check the working. Open “How this was calculated” to see the formula, your values, losses and rounding.
Verify before you act. Use the result for learning and early planning, then check the important decision where shown.

What can change the answer

Check these details

Motors and compressors can need extra power when they start.

Battery age, temperature and a high discharge rate can reduce delivered energy.

Use this as a planning range. Confirm continuous rating, peak rating and battery compatibility with the manufacturer and a qualified installer.

Understand your result

What this answer means

What it means

This joined workflow sizes peak power for the inverter and usable energy for backup duration as two related but separate results.

What to check next

Review the appliance list, motor surge, bank voltage and desired essential-load duration with a qualified installer.

Common mistake

Using the peak load for every backup hour can oversize batteries when high starting demand lasts only seconds.

Common questions

Before you use the result

How is this inverter and battery combined planner calculated?

Inverter VA uses peak load; battery Ah uses average load × backup time

What should I check first?

Review the appliance list, motor surge, bank voltage and desired essential-load duration with a qualified installer.

What mistake should I avoid?

Using the peak load for every backup hour can oversize batteries when high starting demand lasts only seconds.

How accurate is this calculator?

Use this as a planning range. Confirm continuous rating, peak rating and battery compatibility with the manufacturer and a qualified installer.

Sources and method

Sources used for this calculator

Documented dimensional-analysis formulasGharGanit editorial methodologyFormulas are derived from units and expose every editable efficiency, density, dry-volume and wastage assumption. Reviewed 2026-07-16.

Inverter and Battery Combined Planner

Your values

How to use this calculator

Check these details

What this answer means

Before you use the result

Sources used for this calculator

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