Electricity Bill Calculator: Estimate Your Bill From Units Used

Enter the units (kWh) you used and the tariff from your bill. Choose a flat rate or three slabs, add fixed charges and duty, and see the estimated bill, your average cost per unit and the cost per day.

FreeNo sign-upRuns in your browserUpdated 2 Nov 2026
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Estimates only. Check important results before you rely on them.

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How to use this calculator

  1. Enter the units consumed from your meter or bill.
  2. Pick flat rate, or enter your slab limits and rates.
  3. Add the fixed charges and the duty percentage shown on your bill.
  4. Read the estimated bill and the cost per day.

The formula

Energy charge = Units × Rate for a flat tariff. For slabs: charge each band of units at its own rate and add them. Bill = (Energy charge + Fixed charges) × (1 + Tax ÷ 100).

Worked example

For 350 units on slabs of 100 at ₹3, the next 200 at ₹5 and the rest at ₹7: 300 + 1,000 + 350 = ₹1,650. Add ₹50 fixed charges for a bill of ₹1,700 with no tax, or about ₹56.67 per day over 30 days.

Understanding your result

The average cost per unit is always higher than your base rate because fixed charges and tax are spread over the units. A bigger share in higher slabs pushes the average up.

When to use it

  • Predict next bill before it arrives.
  • See how much cutting 50 units would save.
  • Compare a flat plan with a slab plan.

Assumptions and limits

Tariffs differ by state, supplier and customer type, and may include subsidies, surcharges or time-of-day rates. The sample slab values are only a starting point: replace them with the figures from your own bill.

Frequently asked questions

How is an electricity bill calculated?

Units used are charged at the tariff rate, fixed charges are added, and duty or tax is applied on top.

What are slab rates?

Different rates for different bands of usage. The first units are cheaper and units beyond a limit cost more.

Where do I find my rate?

Your tariff is printed on the bill or published by your electricity board.

What is one unit of electricity?

One unit is 1 kilowatt-hour (kWh): a 1,000 W appliance running for one hour.

Will the estimate match my actual bill?

It will be close if you enter the exact tariff. Subsidies and surcharges can cause differences.