How to Calculate TNEB Electricity Bill (Updated Tariff)
Learn how to calculate your Tamil Nadu Electricity Board (TNEB) bill with our free online calculator. Understand the latest tariff slabs and rates.
Understanding your electricity bill is the first step towards saving energy and money. In Tamil Nadu, the electricity tariff for domestic consumers works on a slab system, which can sometimes be confusing.
In this guide, we'll break down exactly how the TNEB (Tamil Nadu Generation and Distribution Corporation) calculates your bill and provide a simple calculator to do the math for you.
How the TNEB Tariff Works
For domestic connections (Tariff IA), TNEB uses a bi-monthly billing cycle. This means your meter reading is taken once every two months, and you pay for the consumption of those 60 days.
The rates mentioned here are based on the latest tariff order. You can view the official TNERC Tariff Order here.
The government of Tamil Nadu provides the first 100 units of electricity completely free for all domestic consumers, regardless of how much you consume in total.
The "500 Unit" Threshold
This is the most critical part of the calculation. TNEB has two different tariff structures based on your total bi-monthly consumption:
Scenario A: If you consume 500 units or less
You enjoy subsidized rates. The calculation is straightforward:
- 0 - 100 units: Free
- 101 - 200 units: ₹2.35 per unit
- 201 - 400 units: ₹4.70 per unit
- 401 - 500 units: ₹6.30 per unit
For example, if you consume 350 units:
- First 100 = 0
- Next 100 (101-200) = 100 × 2.35 = ₹235
- Remaining 150 (201-350) = 150 × 4.70 = ₹705
- Total Energy Charges = ₹940
Scenario B: If you consume more than 500 units
If your consumption crosses 500 units, you lose the lowest subsidy tier (₹2.35) entirely. The slab for 101-400 units is charged at a flat ₹4.70.
- 0 - 100 units: Free
- 101 - 400 units: ₹4.70 per unit
- 401 - 500 units: ₹6.30 per unit
- 501 - 600 units: ₹8.40 per unit
- 601 - 800 units: ₹9.45 per unit
- 801 - 1000 units: ₹10.50 per unit
- Above 1000 units: ₹11.55 per unit
Crossing 500 units can significantly jump your bill. Consuming 501 units vs 500 units isn't just a marginal difference. You lose the subsidy on the 101-200 slab, which adds an extra cost of roughly ₹235 immediately to your bill.
Other Tariff Categories (LT)
While domestic connections (LT Tariff I-A) are the most common, many users also need to calculate bills for commercial or industrial purposes. Here are the rates for other major categories:
Commercial & General (LT Tariff V)
This applies to shops, offices, and general commercial establishments. Unlike domestic users, commercial users pay a higher fixed charge based on their connected load.
| Consumption Slab | Energy Charge (per unit) | Fixed Charge (per kW/2 months) |
|---|---|---|
| 0 - 100 units | ₹6.20 | ₹214 |
| Above 100 units | ₹9.10 | ₹696 |
Industries & IT Services (LT Tariff III-B)
For industrial units and IT services using Low Tension supply:
| Energy Charge | ₹8.55 / unit (flat rate) |
| Fixed Charge | ₹696 / kW (for 2 months) |
Cottage & Tiny Industries (LT Tariff III-A1)
Smaller industrial units enjoy a slightly subsidized rate:
| Consumption Slab | Energy Charge | Fixed Charge |
|---|---|---|
| 0 - 500 units | ₹4.80 | ₹0 |
| Above 500 units | ₹6.95 | ₹150 / kW |
Other Categories
| Category | Energy Charge (per unit) | Fixed Charge |
|---|---|---|
| LT I-C (Bulk Supply) | ₹8.55 | ₹214 / Service |
| LT I-D (Common Lighting/Water) | ₹8.55 | ₹214 / kW |
| LT II-A (Public Lighting) | ₹8.55 | ₹214 / kW |
| LT VI (Temporary Supply) | ₹13.40 | ₹696 / kW / Month |
How Solar Helps
Since the tariff is telescopic and increases with consumption, staying in the lower slabs is key. Installing a solar sytem can help offset your consumption. Even a small 2-3kW system can bring a heavy consumer (>500 units) back into the subsidized brackets or eliminate the bill entirely.
Use our main solar calculator to see how much you can save by switching to solar.