Electricity Unit (kWh) Calculator
Calculate your electricity consumption in units (kWh) and estimate your bill based on appliance usage.
About this calculator
Convert appliance usage into kWh units and estimate the bill at your rate per unit.
How to use it
- List each appliance with its watts, hours per day and days.
- Set the rate per unit.
- Press Calculate and read the units and bill.
The formula
Units (kWh) = watts × hours per day × days ÷ 1000. A 1,500 W AC running 8 hours for 30 days uses 1500 × 8 × 30 ÷ 1000 = 360 units. Bill = units × rate + fixed charges (plus taxes and duty in your state). Real tariffs are in slabs: the first units cost less, and higher slabs cost more, so a flat average is only an estimate. Check your state electricity board's tariff order for exact slabs.
Worked example
Monthly estimate at ₹6.50 per unit
| AC 1.5 ton, 8 h/day | 360 units = ₹2,340 |
| Refrigerator, 24 h/day at 150 W | 108 units = ₹702 |
| LED TV 60 W, 5 h/day | 9 units = ₹58.50 |
| Total | 477 units = ₹3,100.50 + ₹100 fixed = ₹3,200.50 |
Calculated in your browser. Nothing is uploaded.
Tips and common mistakes
- Inverter ACs and 5-star appliances use much less power.
- Set the AC to 24 to 26°C; each degree lower adds roughly 6% to usage.
- Switch to LED: a 9 W LED replaces a 60 W bulb.
- Refrigerator duty cycle is lower than 24 h; use 150 W × 24 only as an upper bound.
- Standby loads (TV, set-top box, chargers) can add up to 5 to 10%.
Frequently asked questions
How are electricity units calculated?
One unit is one kilowatt-hour: 1000 watts used for one hour.
How do I calculate my bill?
Total units × tariff + fixed charges + taxes.
Why does my actual bill differ?
Slab rates, fuel surcharge, taxes and meter readings.
How many units does an AC use?
A 1.5 ton AC uses about 1.2 to 1.5 units per hour.
How can I reduce my bill?
Use efficient appliances and AC at 24 to 26°C.
Is it free?
Yes.