Is this calculator free?

Yes — free, no sign-up, no reference number required.

Which tariff year is this based on?

The most recent NEPRA notification for 2025-26. We update whenever NEPRA revises rates.

K-Electric's tariff mirrors the national inclining-block structure, so the estimate applies with a small margin of error.

APPLIANCE

Enter battery Ah, inverter efficiency and load; get backup minutes.

Battery AhBattery voltageNumber of batteriesTotal load (W)Inverter efficiency (%)Depth of discharge (%)Lead-acid ~50-60%, Lithium ~80-90%

Usable energy1,728 Wh

Backup time259 minutes (4.3 hours)