Estimate your electricity bill before it arrives. Enter the units you have used, your rate per unit, any fixed charge and tax, and see a simple breakdown of the total.
Electricity Bill Calculator
Energy charge (units × rate):
Fixed charge:
Tax amount:
Total bill:
Tax is calculated on the energy charge plus the fixed charge. Your provider may add other charges — check your bill for the exact breakdown.
Our guide walks through a real bill step by step: How to Estimate Your Electricity Bill from Units
How to use the Electricity Bill Calculator
- Work out your units used: take this month’s meter reading and subtract last month’s — the difference is your units consumed (kWh). Your last bill shows both readings.
- Enter that number in the “Units consumed (kWh)” box.
- Enter the “Rate per unit” from your bill.
- Add the “Fixed / service charge” and the “Tax (%)” if your bill has them. An empty box counts as zero.
- Press “Calculate Bill” and read the breakdown: energy charge, fixed charge, tax amount, and the total.
The formula
The working is in three parts. First, the energy charge: units consumed × rate per unit. That is the cost of the electricity itself. Second, the fixed or service charge is added — the standing fee your provider charges for the connection, whether you used a little or a lot. Third, tax is worked out as a percentage of the energy charge plus the fixed charge, and added on top.
So the full sum is: total = (units × rate) + fixed charge + tax. The tool shows each line separately rather than just the final figure, so you can match it against a real bill and spot what has gone up when a bill comes in higher than expected.
Worked example
Say you used 300 units this month, your rate is 30 per unit, your fixed charge is 200, and there is no tax on the bill. Enter 300 as the units, 30 as the rate, 200 as the fixed charge, and leave the tax box empty.
The energy charge is 300 × 30 = 9,000. Adding the fixed charge of 200 gives a total bill of 9,200. That is the figure shown, with the tax amount listed as 0.00. If your bill does include tax, enter its percentage and watch the total rise by that share of 9,200.
Common mistakes
- Entering the meter reading itself instead of the units used. A reading of 14,520 is not your usage — your usage is the gap between this reading and last month’s.
- Using one flat rate when your provider charges slab rates — less for the first block of units, more above it. A flat-rate estimate can then differ from the real bill.
- Mixing currencies — for instance, taking the rate from a sample bill in one currency and the fixed charge from your own bill in another.
- Forgetting extra lines on the real bill, such as fuel adjustments, meter rent, or arrears carried over, which sit outside the basic calculation.
Frequently asked questions
Q: Why is my estimate different from my actual bill?
Usually because of slab rates or extra charges. If your provider prices units in blocks, or adds fuel adjustments, duties, or late payment surcharges, the real bill will differ from a flat-rate estimate. The estimate still helps you check that a bill is roughly right.
Q: What exactly is one unit of electricity?
One unit is one kilowatt-hour (kWh): the electricity used by a 1,000-watt appliance running for one hour. A 100-watt bulb would need to run for ten hours to use a single unit.
Q: How can I bring my units down next month?
Start with the heavy items: air conditioners, electric heaters, water heaters and irons use far more than lights and fans. Compare this month’s reading gap with last month’s after any change — the saving shows in units before it shows in money.