How to Calculate Your Electricity Bill Accurately – Step-by-Step Guide
To calculate your electricity bill in India: 1) Subtract previous meter reading from current reading to get units consumed (kWh); 2) Multiply units across progressive slab brackets by their respective rates; 3) Add monthly fixed capacity charges (₹/kW); 4) Add statutory electricity duty and fuel surcharges (FAC); and 5) Deduct state government subsidy relief.
Units (kWh) = (Wattage × Hours) ÷ 1,000Net Bill = (Slab Energy Charges) + (Fixed Load Fee) + (Duty & FAC) – (Subsidy)1. The Core Electricity Bill Formula Explained
An electricity bill in India is not simply Units × Flat Rate. Instead, state electricity regulatory commissions (SERCs) mandate a multi-component billing formula consisting of five distinct items:
Breakdown of Bill Components:
- Energy Charges (EC): The cost of the actual electrical energy consumed, measured in kilowatt-hours (kWh) or units, billed in progressive slab brackets.
- Fixed Charges (FC): Monthly capacity/demand charge based on your sanctioned load in kW (e.g. ₹50 to ₹120 per kW per month).
- Fuel Adjustment Surcharge (FAC/FPPPA): Variable per-unit fee reflecting changes in power purchase costs from generating stations.
- Electricity Duty (ED): State government statutory tax (ranging from 5% in MP to 16% in Maharashtra) levied on energy and fixed charges.
- Government Subsidy: Direct state benefits such as 200 free units in Delhi and Karnataka, or 300 free units in Punjab.
2. Telescopic vs Non-Telescopic Slab Billing
Understanding how your state applies tariff slabs is the most critical part of manual bill calculation:
🪜 Telescopic Billing (Most States)
Used in Maharashtra (MSEDCL), Uttar Pradesh (UPPCL), Delhi (BSES), and Tamil Nadu (TNEB). Each block of units is charged only at its respective bracket rate.
• Units 0–100 @ ₹3.50 = ₹350
• Units 101–200 @ ₹5.00 = ₹500
• Units 201–250 @ ₹7.00 = ₹350
Total Energy Charge = ₹1,200
⚠️ Non-Telescopic Billing
Hypothetical rates for illustration onlyUsed in Kerala (KSEB for >250 units). If you cross the 250-unit threshold, the entire consumption from unit 1 is billed at a single flat high rate.
• All 255 units @ ₹7.50 flat = ₹1,912.50
Total Energy Charge = ₹1,912.50
(Crossing by just 5 units raises bill significantly!)
3. Worked Example: Step-by-Step 300 Units Calculation
Hypothetical rates for illustration onlyLet us calculate the bill for a domestic household with a 2 kW Sanctioned Load consuming 300 units in a month (hypothetical rates for illustration only; verify against your state utility's active tariff schedule):
| Step | Component | Calculation Formula | Amount (₹) |
|---|---|---|---|
| 1 | Slab 1 (0–100 units) | 100 units × ₹4.00/unit | ₹400.00 |
| 2 | Slab 2 (101–200 units) | 100 units × ₹6.00/unit | ₹600.00 |
| 3 | Slab 3 (201–300 units) | 100 units × ₹8.00/unit | ₹800.00 |
| 4 | Subtotal Energy Charges | ₹400 + ₹600 + ₹800 | ₹1,800.00 |
| 5 | Fixed Demand Charges | 2 kW load × ₹75.00/kW | ₹150.00 |
| 6 | Fuel Adjustment (FAC) | 300 units × ₹0.20/unit | ₹60.00 |
| 7 | Electricity Duty (5%) | 5% of (₹1,800 + ₹150) | ₹97.50 |
| Total | Estimated Net Payable Bill | Sum of Steps 4 through 7 | ₹2,107.50 |
4. What is 1 Unit of Electricity? (1 Unit = 1 kWh Conversion & Watts Formula)
In electrical metering across India and worldwide, 1 Unit of electricity is exactly equal to 1 Kilowatt-Hour (1 kWh). This represents 1,000 Watts of electrical power used continuously for 1 hour:
Units (kWh) = (Total Appliance Wattage in Watts × Operating Hours) ÷ 1,000
Example: Running a 200W air cooler for 5 hours = (200W × 5 hrs) ÷ 1000 = 1.0 kWh = 1 Electricity Unit.
| Appliance Wattage | Daily Operating Hours | Daily Units (kWh) | Monthly Units (30 Days) |
|---|---|---|---|
| LED Bulb (10 Watts) | 10 Hours | 0.10 kWh | 3.0 Units |
| BLDC Ceiling Fan (28 Watts) | 12 Hours | 0.34 kWh | 10.1 Units |
| Standard Ceiling Fan (75 Watts) | 12 Hours | 0.90 kWh | 27.0 Units |
| Desert Air Cooler (200 Watts) | 8 Hours | 1.60 kWh | 48.0 Units |
| 1.5 Ton 5-Star Inverter AC (1,200 Watts) | 8 Hours | 9.60 kWh | 288.0 Units |
| Induction Cooktop (1,800 Watts) | 1.5 Hours | 2.70 kWh | 81.0 Units |
| Water Geyser (2,000 Watts) | 1 Hour | 2.00 kWh | 60.0 Units |
5. State-Wise 1 Unit Electricity Price & Base Tariff Rates in India (FY 2026–27)
The base rate for 1 unit of domestic electricity varies across states based on state regulatory commission orders (SERCs) and government lifeline subsidies:
| State / Jurisdiction | DISCOMs / Boards | Billing Cycle | 1 Unit Base Rate (₹) | Lifeline Subsidy Policy | Dedicated Tool |
|---|---|---|---|---|---|
| Delhi | BSES Rajdhani (BRPL), BSES Yamuna (BYPL), Tata Power DDL (TPDDL), NDMC | Monthly | ₹3.00/unit | Delhi Govt provides 100% subsidy up to 200 units and 50% subsidy (max ₹800) for 201-400 units. | Delhi Calculator → |
| Tamil Nadu | TNPDCL (formerly TANGEDCO/TNEB) | Bi-Monthly | ₹0.00/unit | Subsidy scheme (effective 10 May 2026, per published reports; primary documents not yet reviewed; G.O. (Ms) No. 50 dated 10 May 2026, TNERC Order No. 5 of 2026 (date not yet confirmed)): households consuming UP TO 500 units bi-monthly receive the first 200 units FREE. For consumption 201–400 units: ₹4.70/unit; 401–500 units: ₹6.30/unit. Households consuming MORE THAN 500 units bi-monthly revert to the older structure where only the first 100 units are free. Exact slab rates above 500 units require verification from TNPDCL. | Tamil Nadu Calculator → |
| Karnataka | BESCOM, MESCOM, HESCOM, GESCOM, CESC Mysore | Monthly | ₹5.80/unit | Eligible domestic consumers registered under Karnataka Gruha Jyothi receive up to 200 free units/month. Each household's monthly free-unit entitlement is personalized based on past consumption patterns, up to a maximum of 200 units; the exact calculation method should be confirmed with BESCOM or via the Seva Sindhu portal. Consumers whose consumption exceeds entitlement pay only for the excess units above their subsidized limit; there is no cliff-edge forfeiture. Rates (₹5.80/unit) and 9% duty are illustrative estimates; confirm with your bill. | Karnataka Calculator → |
| Punjab | PSPCL (Punjab State Power Corporation Limited) | Bi-Monthly | ₹4.19/unit | Punjab Government provides 300 free units per month (600 bi-monthly) for all domestic consumers. | Punjab Calculator → |
| Maharashtra | MSEDCL (Mahadiscom), Adani Electricity Mumbai, Tata Power Mumbai, BEST | Monthly | ₹3.25/unit | FAC (Fuel Adjustment Charge) applied quarterly under MERC Multi-Year Tariff Order. | Maharashtra Calculator → |
| Uttar Pradesh | UPPCL, PVVNL, MVVNL, DVVNL, PuVVNL, NPCL Noida | Monthly | ₹3.35/unit | Lifeline consumers (up to 100 units & 1kW) get reduced slab rate of ₹3.35. | Uttar Pradesh Calculator → |
| Gujarat | DGVCL, MGVCL, PGVCL, UGVCL, Torrent Power | Monthly | ₹3.20/unit | FPPPA (Fuel Price and Power Purchase Adjustment) charge is significant in Gujarat (~₹2.85/unit). | Gujarat Calculator → |
| Kerala | KSEB (Kerala State Electricity Board) | Bi-Monthly | ₹2.90/unit | Telescopic pricing up to 250 units monthly; non-telescopic rates apply above 250 units. | Kerala Calculator → |
| West Bengal | WBSEDCL, CESC Limited | Monthly | ₹5.04/unit | WBSEDCL domestic tariffs vary by urban/rural category and billing arrangement; this page uses the urban monthly-equivalent benchmark. Electricity duty and subsidy eligibility can change with consumption and category. | West Bengal Calculator → |
| Telangana | TGSPDCL (TSSPDCL), TGNPDCL (TSNPDCL) | Monthly | ₹1.95/unit | Gruha Jyothi Scheme in Telangana provides up to 200 free units/month for eligible households holding a food security card. Usage above 200 units forfeits the subsidy and is billed under TSERC LT-1 category re-rated rates. | Telangana Calculator → |
Calculate Automatically for Your State
Select your state or electricity distribution board below to calculate your exact monthly power bill with automated slab progression, load demand fees, and subsidy deductions:
Electricity Bill Calculator
Accurate billing computation applying state regulatory tariff orders, progressive slab tiers, demand capacity, and statutory duties.
Energy Cost Flow
Sequential billing breakdown from metered draw to billed total
| Slab Range | Units | Rate | Amount |
|---|---|---|---|
| 0 – 200 units | 200 | ₹3.00 | ₹600.00 |
| 201 – 400 units | 50 | ₹4.50 | ₹225.00 |
7. Frequently Asked Questions (FAQs)
What is the formula to calculate electricity bill in India? ▼
Total Bill Amount = Energy Charges (Σ Units in each slab × Slab rate) + Fixed Charges (Sanctioned Load in kW × Rate/kW) + Fuel Adjustment Surcharge (FAC per unit × Total Units) + Electricity Duty (% of Energy + Fixed charges) – Government Subsidy (if applicable).
What is 1 unit of electricity in kWh? ▼
1 Unit of electricity is exactly equal to 1 Kilowatt-Hour (1 kWh) or 1,000 Watt-hours. For example, running a 1,000 Watt appliance for 1 hour consumes exactly 1 unit of electricity. Formula: Units (kWh) = (Wattage in Watts × Operating Hours) ÷ 1,000.
What is the cost of 1 unit of electricity in India in rupees? ▼
In India, the cost of 1 unit of electricity for domestic consumers ranges from ₹0 (under subsidy schemes in Delhi, Punjab, Karnataka, and Tamil Nadu) to ₹3.05–₹4.50/unit in base slabs, rising to ₹7.00–₹16.64/unit in higher consumption slabs (such as Maharashtra and West Bengal).
How do you convert Watts to electricity units? ▼
To convert Watts to electricity units (kWh): Multiply appliance wattage by operating hours and divide by 1,000. Example: A 200 Watt cooler running for 5 hours = (200 × 5) ÷ 1,000 = 1 Unit of electricity.
What is the difference between telescopic and non-telescopic billing? ▼
In telescopic billing, your consumption is divided across tiered brackets (e.g., first 100 units at ₹3.50, next 100 units at ₹5.00). In non-telescopic billing, once your total consumption exceeds a threshold (e.g. 250 units in Kerala KSEB), all units from 1 to 250+ are billed at a single, higher flat rate.
How do I calculate electricity units from my meter reading? ▼
Read the current cumulative number displayed when 'kWh' appears on your digital meter. Subtract your last billed reading: (Current Meter Reading − Previous Meter Reading = Total Units Consumed). Example: 4,520 kWh − 4,220 kWh = 300 Units.
Why does my bill include fixed charges even when power consumption is zero? ▼
Fixed charges (also called sanctioned demand charges) cover the electricity board's infrastructure maintenance, grid connection, and transmission capacity costs. They are billed every month based on your sanctioned load (kW), regardless of whether power is consumed.
What is FAC / FPPPA on my power bill? ▼
FAC (Fuel Adjustment Charge) or FPPPA (Fuel Price and Power Purchase Adjustment) is a variable surcharge levied by state utilities to pass through quarterly fluctuations in coal, gas, and power generation procurement costs.