Quick Answer
Your electricity bill = units used × the slab rates + fixed charge + duty. Most Indian boards use telescopic slabs, where each rate applies only to the units in that slab. With example rates of ₹3 (0–100), ₹4.50 (101–200) and ₹6 (201–400), 250 units cost ₹300 + ₹450 + ₹300 = ₹1,050 in energy charges; adding a ₹100 fixed charge and 5% duty gives ₹1,207.50. Units = watts × hours × days ÷ 1000, so a 1,500 W AC run 8 hours a day uses about 360 units a month.
What is an Electricity Bill Calculator?
An electricity bill calculator (बिजली बिल कैलकुलेटर) estimates your power bill from the units you use and your electricity board's tariff. It is useful for checking a bill that looks too high, budgeting for summer when the AC runs every day, comparing appliances before you buy, or simply understanding where your money goes.
This free tool works two ways. If you know your units or meter readings, it applies your board's slab rates, fixed charge and duty to calculate the bill with a slab-by-slab breakdown. If you don't, it estimates units from a list of appliances — watts, quantity and hours per day. The rates are fully editable, because every state and DISCOM has its own tariff.
Key Features
- Bill from units or meter readings.
- Editable telescopic slabs — 0–100, 101–200, 201–400 and above 400 units.
- Fixed charge and duty / tax %.
- Appliance estimator with editable watts and hours.
- Slab-wise table and average cost per unit.
- Free and private.
How to Use It
- Choose I know my units and enter your units — or the previous and current meter readings.
- Or choose Estimate from appliances, edit the list and set the billing days.
- Replace the example slab rates with the rates on your bill.
- Enter the fixed charge and duty %.
- Read the estimated bill, the breakdown and your average cost per unit.
How the Bill is Calculated
Units
Units (kWh) = Current reading − Previous reading. For appliances: Units = Watts × Hours per day × Days ÷ 1000.
Telescopic slab charges
Most Indian residential tariffs are telescopic: each slab's rate applies only to the units within it. With the example rates of ₹3, ₹4.50, ₹6 and ₹7.50 per unit, 250 units are charged as:
- First 100 units × ₹3 = ₹300
- Next 100 units × ₹4.50 = ₹450
- Last 50 units × ₹6 = ₹300
- Energy charge = ₹1,050
Add a ₹100 fixed charge and 5% duty on ₹1,150 (₹57.50): total ₹1,207.50, an average of about ₹4.83 per unit.
Bill at Different Usage (example tariff)
| Units | Energy charge | Duty (5%) | Total with ₹100 fixed |
|---|---|---|---|
| 80 | ₹240.00 | ₹17.00 | ₹357.00 |
| 150 | ₹525.00 | ₹31.25 | ₹656.25 |
| 250 | ₹1,050.00 | ₹57.50 | ₹1,207.50 |
| 400 | ₹1,950.00 | ₹102.50 | ₹2,152.50 |
| 600 | ₹3,450.00 | ₹177.50 | ₹3,727.50 |
These figures use the example tariff only. Notice how the bill grows faster than usage: going from 400 to 600 units adds ₹1,575, because the extra units fall in the most expensive slab.
How Many Units Do Appliances Use?
| Appliance | Typical power | Use per day | Units a month (30 days) |
|---|---|---|---|
| LED bulb | 9 W | 6 h | 1.6 each |
| Ceiling fan (standard) | 75 W | 10 h | 22.5 each |
| Ceiling fan (BLDC) | 30 W | 10 h | 9 each |
| LED TV | 100 W | 4 h | 12 |
| Refrigerator (average draw) | ~60 W | 24 h | ~43 |
| AC 1.5 ton | ~1,500 W | 8 h | ~360 |
| Geyser | 2,000 W | 30 min | 30 |
| Washing machine | 500 W | 30 min | 7.5 |
Real consumption varies with the model, star rating, settings and how hard the appliance works. ACs and fridges cycle on and off, so their average draw is usually below the nameplate wattage. For the most accurate figure, check the BEE star label, which shows yearly energy consumption in kWh.
The AC Effect
In summer the air conditioner often dominates the bill. One 1.5-ton AC drawing 1,500 W for 8 hours a day uses about 360 units a month — more than many homes use for everything else combined, and enough to push the whole bill into higher slabs. Inverter ACs with a good star rating, a setting of 24–26 °C, closed doors and windows, clean filters and a ceiling fan for circulation can cut that significantly.
Example: A Family's Winter vs Summer Bill
The appliance list in the calculator starts with a typical small home: five LED bulbs for 6 hours, three ceiling fans for 10 hours, a refrigerator, a TV for 4 hours and a washing machine for half an hour a day. That adds up to about 138 units a month, or roughly ₹601 with the example tariff. Now switch on a 1.5-ton AC for 8 hours a day in summer: usage jumps by about 360 units to 498 units, and the bill to roughly ₹2,927 — nearly five times higher, because the extra units land in the expensive top slabs. This is why summer bills shock so many households, and why AC efficiency and settings matter so much.
Domestic, Commercial and Other Tariffs
Boards set separate tariffs for domestic, commercial, agricultural and industrial connections, and sometimes different rates for urban and rural areas, or time-of-day pricing for larger loads. A shop or office usually pays a higher per-unit rate than a home. Some tariffs are not telescopic: once usage crosses a limit, every unit is charged at a higher rate. If your bill works that way, enter the same rate in all four slabs for the band you fall in. The calculator is flexible enough for most residential structures, but your bill and the tariff order remain the final authority.
Reading Your Electricity Bill
- Previous and present reading — the difference is your units.
- Sanctioned or connected load — often decides the fixed charge.
- Energy charges — units × slab rates.
- Fixed / demand charge — a flat monthly amount.
- Electricity duty — a state levy.
- Fuel or power purchase adjustment — a variable per-unit surcharge some boards add.
- Subsidy — some states provide free units or rebates for eligible households.
Use the rates and charges printed on your own bill in the calculator for the closest estimate. If your board adds a per-unit adjustment, add it to each slab rate.
Free Units and Subsidies
Several states offer free or subsidised electricity up to a monthly limit for eligible households. To model this, set the rate for the free units to ₹0 — for example, if the first 100 units are free, enter 0 in the 0–100 slab. If the subsidy is a fixed rebate, subtract it from the calculator's total. Eligibility rules differ, so check your state's scheme.
Ways to Cut Your Bill
- Switch to LED lights everywhere.
- Replace old fans with BLDC fans.
- Buy 5-star appliances — the higher price is often recovered through lower bills.
- Set the AC to 24–26 °C and use a timer at night.
- Turn off devices at the plug — standby power adds up.
- Run washing machines and dishwashers full.
- Consider rooftop solar — check government schemes and net-metering rules in your state.
- Service your AC and fridge — clean filters and coils help them run efficiently.
- Use natural light and ventilation during the day where you can.
Common Mistakes
- Charging all units at the top slab rate instead of telescopic slabs.
- Using nameplate watts for fridges and ACs, which overstates use.
- Forgetting fixed charges and duty.
- Using another state's tariff — always enter your own.
- Comparing bills of different lengths — some boards bill every two months, so compare units per day instead.
Quick Glossary
- kWh / unit: 1,000 watts for one hour.
- DISCOM: your electricity distribution company.
- Tariff order: the regulator's document setting rates.
- Sanctioned load: the maximum load approved for your connection.
- BEE star label: the energy-efficiency rating on appliances.
Why Use This Calculator?
It applies telescopic slabs correctly, lets you enter your own board's tariff, estimates units from appliances and shows exactly how each slab and charge adds up. It is free, private and works on any phone. To compare running costs on the road, try our Fuel Cost Calculator.
Electricity Bill Calculator — Key Facts
| 1 unit | 1 kWh = 1,000 watts for 1 hour |
|---|---|
| Units from appliance | Watts × hours × days ÷ 1000 |
| Telescopic slabs | Each rate applies only to its slab |
| Example | 250 units → ₹1,207.50 (example tariff) |
| 1.5-ton AC, 8 h/day | About 360 units a month at 1,500 W |
| Tariff | Varies by state and DISCOM — enter yours |
Frequently Asked Questions
How is an electricity bill calculated?
Units used (kWh) are charged at slab rates set by your state's electricity regulator, then a fixed or meter charge, electricity duty and any other charges or subsidies are added. The exact structure depends on your DISCOM and connection type.
What is 1 unit of electricity?
One unit is one kilowatt-hour (kWh): 1,000 watts used for one hour. A 100 W bulb running for 10 hours uses 1 unit.
How do I calculate units from meter readings?
Subtract the previous reading from the current reading. If last month showed 12,450 and this month 12,700, you used 250 units.
What are telescopic slabs?
Each slab's rate applies only to the units within that slab. Using 250 units, the first 100 are charged at the first-slab rate, the next 100 at the second and the last 50 at the third. Some tariffs instead charge all units at one rate once you cross a limit — check your bill.
How many units does an AC use?
Roughly its power in kW × hours. A 1.5-ton AC drawing about 1,500 W for 8 hours uses about 12 units a day, or 360 a month. Inverter and higher star-rated ACs often use noticeably less, depending on temperature setting and room conditions.
How many units does a fridge use?
A refrigerator's compressor switches on and off, so its rated wattage overstates use. Many household fridges average roughly 1–1.5 units a day; the BEE star label shows the yearly energy use, which you can divide by 12.
How many units does a fan use?
A typical 75 W ceiling fan running 10 hours uses 0.75 units a day, about 22 units a month. BLDC fans use around 28–35 W, cutting that by more than half.
Why are the default rates an example?
Tariffs differ by state, DISCOM, connection type, load and season, and they are revised by regulators. Copy the rates from your latest bill or your DISCOM's tariff order for an accurate estimate.
What is the fixed charge?
A monthly charge based on sanctioned load or connection, paid regardless of units used. Some boards call it a meter rent or demand charge.
Does the calculator include subsidies?
Not automatically. If your state gives free units or a subsidy, set the first slab's rate to 0 for the free units, or subtract the subsidy from the result.
How can I reduce my bill?
Use LED lights, BLDC fans and 5-star appliances, set the AC to 24–26 °C, switch off devices at the plug, and run heavy appliances efficiently. Even small changes add up over a year.
Is the electricity bill calculator free?
Yes, free and private. Nothing is sent to any server.
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