Demystifying Your Electricity Bill: How Power Discoms Across India Calculate Charges
Electricity is an indispensable household utility powering our lights, ceiling fans, inverter air conditioners, water heaters, and consumer appliances. Yet, for millions of Indian homeowners and tenants across all 28 States and 8 Union Territories, receiving the monthly or bi-monthly power bill is often a source of confusion. Electricity distribution companies (Discoms) utilize multi-tiered telescopic and non-telescopic tariff slabs, variable fixed demand charges, fuel adjustment costs (FAC / FPPCA), electricity duties, and state-sponsored welfare subsidies (such as 100 free units in Tamil Nadu, 200 free units in Delhi and Karnataka, or 300 free units in Punjab).
Understanding how every kilowatt-hour (kWh) translates into your final electricity bill empowers you to audit energy usage, pinpoint high-wattage vampire appliances, and take proactive steps to slash household utility expenses. You can also budget your household income against recurring utilities using our Salary Breakup Calculator, In-Hand Salary Calculator, and Daily Wage Calculator.
Our free, interactive EB Bill Calculator (Electricity Bill Calculator) provides instant tariff calculations for all Indian states—including TNEB / TANGEDCO (Tamil Nadu), MSEDCL (Maharashtra), BESCOM (Karnataka), BSES / TPDDL (Delhi), TSSPDCL (Telangana), UPPCL (Uttar Pradesh), PSPCL (Punjab), KSEB (Kerala), and WBSEDCL (West Bengal)—alongside meter reading diff tools and an appliance wattage power auditor.
1. Mathematical Formulas: Converting Appliance Watts to Units (kWh) and Rupees
Electricity is billed based on Units, where 1 unit represents 1 Kilowatt-hour (kWh) of electrical energy:
Example: Operating a 1.5 Ton AC
Suppose a 1.5 Ton 3-Star Split AC consumes 1,500 Watts (1.5 kW) and runs for 8 hours every day for a month (30 days):
- Daily Consumption: ( 1,500 W × 8 h ) / 1000 = 12.0 Units / day.
- Monthly Consumption: 12.0 Units × 30 Days = 360.0 Units / month.
- Estimated Cost (at an average rate of ₹6.50/unit): 360 × ₹6.50 = ₹2,340.00 per month just for the AC!
2. Understanding Telescopic vs. Non-Telescopic Tariff Slabs
State Electricity Regulatory Commissions (SERCs) classify domestic consumer tariffs into two fundamental structures:
- Telescopic Tariff Structure: The consumer receives the benefit of lower-tier unit prices for initial consumption blocks, regardless of total consumption. For example, if you consume 250 units, the first 100 units are billed at Tier 1 rates, the next 100 at Tier 2 rates, and only the remaining 50 at Tier 3 rates.
- Non-Telescopic / Threshold-Shift Structure: In systems like TNEB (above 500 units), if your total consumption exceeds a statutory threshold, the entire consumption moves to a higher tariff matrix, sharply steepening the bill.
3. All India State-Wise Electricity Tariff Slabs & Subsidy Rules (2026)
A. Tamil Nadu – TNEB / TANGEDCO Domestic Tariff (Bi-Monthly Billing)
TNEB bills residential consumers every 2 months (60-day cycle). The Government of Tamil Nadu provides 100 free units to all domestic consumers:
| Consumption Range (Bi-Monthly) | Unit Slabs | Rate per Unit (₹/kWh) |
|---|---|---|
| Total Consumption Up to 500 Units | 0 to 100 Units | ₹0.00 (100% Free Govt Subsidy) |
| 101 to 200 Units | ₹2.25 / unit | |
| 201 to 400 Units | ₹4.50 / unit | |
| 401 to 500 Units | ₹6.00 / unit | |
| Total Consumption Above 500 Units | 0 to 100 Units | ₹0.00 (Free Subsidy retained) |
| 101 to 400 Units | ₹4.50 / unit | |
| 401 to 500 Units | ₹6.00 / unit | |
| 501 to 600 Units | ₹8.00 / unit (601–800 @ ₹9.00, 801–1000 @ ₹10.00, 1000+ @ ₹11.00) |
B. Maharashtra – MSEDCL / Mahavitaran (Monthly Billing)
| Consumption Slab (Monthly) | Energy Charge (₹/Unit) | Fixed Monthly Charge |
|---|---|---|
| 0 to 100 Units | ₹5.88 / unit | ₹116 / month |
| 101 to 300 Units | ₹11.26 / unit | ₹116 / month |
| 301 to 500 Units | ₹15.72 / unit | ₹116 / month |
| Above 500 Units | ₹17.81 / unit | ₹116 / month |
C. Delhi – BSES Yamuna / Rajdhani & TPDDL
Delhi offers targeted domestic power subsidies:
- 0 to 200 Units: 100% Free Electricity (₹0 Bill under opted subsidy scheme).
- 201 to 400 Units: 50% Subsidy on energy charges (Capped at ₹800).
- Above 400 Units: Standard DERC slab rates (₹6.50 to ₹8.00 / unit) with full fixed charges.
D. Punjab – PSPCL (300 Units Free Power Scheme)
The Government of Punjab provides 300 units of free power per month (600 units bi-monthly) for all domestic connections. If consumption remains under 600 units in a 2-month cycle, the electricity bill is ₹0.
E. Karnataka – BESCOM & Gruha Jyothi Scheme
Under the Gruha Jyothi welfare scheme, eligible domestic consumers receive up to 200 units of free power per month based on their historical average annual consumption + 10% entitlement.
4. How to Read Your Digital Electricity Meter
Digital electronic and smart meters display real-time telemetry metrics cyclically on their LCD screen:
- Identify the kWh Metric: Wait for the screen to cycle through date, time, and voltage until you see a number followed by "kWh" (Kilowatt-Hours). This is your cumulative active energy consumption.
-
Record Current Reading: Note down the integer digits before the decimal point (e.g.
14520). Ignore the decimal fractions. -
Compute Billable Units: Subtract your previous bill’s closing meter reading from this current reading:
Units = 14,520 - 14,170 = 350 Units. - Check Maximum Demand (kW / kVA): If your recorded maximum demand (MD) exceeds your sanctioned load, Discoms levy penalty demand surcharges.
5. Master Home Appliance Power Consumption Chart
To optimize energy usage, here is the benchmark wattage and monthly consumption for standard home appliances:
| Appliance | Average Wattage (W) | Typical Daily Usage | Monthly Units (kWh) | Est. Monthly Cost (at ₹7/U) |
|---|---|---|---|---|
| 1.5 Ton Inverter AC (5-Star) | 1,000 W | 8 Hours | 240 Units | ₹1,680.00 |
| 1.5 Ton Non-Inverter AC | 1,600 W | 8 Hours | 384 Units | ₹2,688.00 |
| Storage Water Geyser | 2,000 W | 1.5 Hours | 90 Units | ₹630.00 |
| Double Door Refrigerator | 250 W | 24 Hours (Duty Cycle) | 45 Units | ₹315.00 |
| Ceiling Fan (Standard Induction) | 75 W | 14 Hours | 31.5 Units | ₹220.50 |
| BLDC Energy Saver Fan | 28 W | 14 Hours | 11.8 Units | ₹82.60 |
| 55-Inch 4K Smart LED TV | 120 W | 6 Hours | 21.6 Units | ₹151.20 |
| Water Submersible Pump (1 HP) | 750 W | 1 Hour | 22.5 Units | ₹157.50 |
6. 10 Proven Strategies to Lower Your Electricity Bill by 30% to 50%
Slash your electricity expenses without sacrificing comfort by adopting these smart energy habits:
- Set AC to 24°C: Setting your air conditioner to 24°C instead of 18°C reduces compressor power draw by approximately 6% per degree Celsius!
- Upgrade to BLDC Fans: Replacing conventional 75W induction fans with 28W Brushless DC (BLDC) motor fans cuts fan electricity consumption by 62%.
- Insulate Geyser Pipes: Turn off water heaters immediately after 15–20 minutes of heating rather than keeping them on thermostat standby.
- Switch to 5-Star Inverter Appliances: Inverter compressors modulate motor speed dynamically, consuming 30%–45% less power than fixed-speed models.
- Banish Vampire Standby Power: Unplug TV set-top boxes, gaming consoles, microwave ovens, and chargers when not in use. Standby loads account for up to 5% of household bills.
- Adopt Rooftop Solar Net Metering: Installing a 3 kW grid-tied solar system generates 12–15 units per day (360–450 units/month), bringing net electricity bills close to zero.
Frequently Asked Questions (FAQs)
What is 1 unit of electricity in India?
1 unit of electricity equals 1 kilowatt-hour (1 kWh). It is the energy consumed by a 1,000-watt appliance running for 1 hour (e.g. running a 1,000W iron box for 60 minutes or a 100W bulb for 10 hours).
How is the TNEB (Tamil Nadu) bi-monthly electricity bill calculated?
TNEB bills consumers once every two months. The Government of Tamil Nadu provides 100 free units for all domestic connections. Slabs apply telescopically up to 500 units (101–200 @ ₹2.25, 201–400 @ ₹4.50, 401–500 @ ₹6.00). If consumption crosses 500 units, higher non-telescopic rates apply.
Which states provide 200 or 300 free electricity units in India?
Punjab provides 300 units free per month (600 bi-monthly), Delhi provides 200 units free per month, Karnataka offers up to 200 units free under Gruha Jyothi, Telangana provides 200 free units under Gruha Jyothi, and Himachal Pradesh provides 125 free units.
How can I calculate my electricity bill from meter readings?
Subtract the previous reading from your current digital meter reading to determine consumed units (Units = Current kWh - Previous kWh). Then multiply units across your discom's tariff slabs and add fixed charges plus electricity duty.
How many units does a 1.5 Ton AC consume in a month?
Running a 1.5 Ton 3-Star AC for 8 hours daily consumes approximately 280 to 360 units per month. A 5-Star Inverter AC running at 24°C uses approximately 200 to 240 units per month.
What are Fixed Charges (Demand Charges) on my EB bill?
Fixed charges (or demand charges) are non-energy statutory fees levied by Discoms to maintain grid infrastructure, transmission lines, and substations based on your sanctioned load (kW), regardless of whether power is consumed.
What is Fuel Adjustment Surcharge (FAC / FPPCA)?
Fuel and Power Purchase Cost Adjustment (FPPCA) is a variable charge approved by State Regulatory Commissions to account for quarterly price fluctuations in coal, gas, and power purchase costs incurred by distribution utilities.
How does rooftop solar net-metering reduce my EB bill?
With net-metering, the bidirectional meter records solar power exported to the grid. At the end of the billing cycle, exported solar units are deducted from consumed units, and you pay only for the net difference.