TNEB Bill Calculator
Work out your Tamil Nadu electricity bill, the price you pay per unit, and what a tariff hike would add.
Calculate from
Electricity charge for 2 months
₹940.00
350 units · about ₹470.00 a month
Average price per unit
₹2.69
Bill ÷ all units, free ones included
Rate of your top slab
₹4.70
What your last units were charged at
Cost of the next unit
₹4.70
Slab-wise breakdown
| Units | Count | Rate (₹/unit) | Amount |
|---|---|---|---|
| 1–100 | 100 | Free | ₹0.00 |
| 101–200 | 100 | 2.35 | ₹235.00 |
| 201–350 | 150 | 4.70 | ₹705.00 |
| Total | 350 | ₹940.00 |
Tariff table used (up to 500 units)
| Slab (units) | Current rate |
|---|---|
| 1–100 | Free |
| 101–200 | ₹2.35 |
| 201–400 | ₹4.70 |
| 401–500 | ₹6.30 |
Domestic (LT-IA) rates in force since 1 July 2024, including the first 100 units free. The final bill may differ slightly for rounding or any arrears or deposits added to the bill.
Enter the units on your Tamil Nadu electricity bill — or the previous and current meter readings — and this calculator applies the domestic (LT-IA) slab tariff to show the bill, the average price you pay per unit, and how each slab contributes. You can also work backwards from a bill amount to the units it covers.
The tariff-increase box answers the other common question: if rates go up by a given percentage, how much more will your bill be? The free first 100 units stay free; every other slab rises by the percentage you enter, and the tool shows the old bill, the new bill and the difference side by side.
Current domestic slab rates
Homes in Tamil Nadu are billed every two months, and which table applies depends on the total for those two months. Up to 500 units you get the cheaper table; above 500, every unit from 101 onwards is charged on the higher one.
| Units (2 months) | Up to 500 units total | Above 500 units total |
|---|---|---|
| 0–100 | Free | Free |
| 101–200 | ₹2.35 | ₹4.70 |
| 201–400 | ₹4.70 | ₹4.70 |
| 401–500 | ₹6.30 | ₹6.30 |
| 501–600 | — | ₹8.40 |
| 601–800 | — | ₹9.45 |
| 801–1000 | — | ₹10.50 |
| Above 1000 | — | ₹11.55 |
Rates in force since 1 July 2024. The 2025 tariff revision was absorbed by the State Government for domestic consumers, so these remain the amounts charged on the bill.
Worked example: 350 units
- 350 is under 500, so the lower table applies.
- Units 1–100 are free: ₹0.
- Units 101–200 are 100 units at ₹2.35: ₹235.
- Units 201–350 are 150 units at ₹4.70: ₹705.
- Total: ₹940 for two months, an average of about ₹2.69 per unit.
The 500-unit cliff
The most expensive unit on a Tamil Nadu bill is the 501st. At 500 units the bill is ₹1,805; at 501 it is ₹2,048.40 — one extra unit costs ₹243.40, because units 101–200 move from ₹2.35 to ₹4.70 the moment you cross the line.
If your usage regularly lands just above 500, trimming a few units — running the AC a degree warmer, switching off a water heater sooner — saves far more than the per-unit rate suggests. The calculator warns you whenever you are within 60 units of the line on either side.
Typical bills at a glance
| Units (2 months) | Bill | Average per unit |
|---|---|---|
| 100 | ₹0 | ₹0.00 |
| 200 | ₹235 | ₹1.18 |
| 300 | ₹705 | ₹2.35 |
| 400 | ₹1,175 | ₹2.94 |
| 500 | ₹1,805 | ₹3.61 |
| 600 | ₹2,880 | ₹4.80 |
| 800 | ₹4,770 | ₹5.96 |
| 1000 | ₹6,870 | ₹6.87 |
Frequently asked questions
- Is this for a monthly or two-monthly bill?
- Two-monthly. TNEB bills domestic connections every two months, and the slabs are defined for that period. If you know only your monthly usage, double it before entering it.
- Are the first 100 units really free?
- Yes. For domestic consumers the State Government subsidises the first 100 units of every two-month bill, whatever your total usage.
- What is the difference between average price and the rate of my top slab?
- The top-slab rate is what your last few units were charged at. The average spreads the whole bill over all units, including the free 100, so it is always lower. The average is the fairer figure for comparing bills; the top-slab rate tells you what saving one more unit is worth.
- How is a tariff increase applied?
- Enter the percentage and every paid slab rate is multiplied by it. The free 100 units stay free, so the rise in your total bill is a little smaller, in rupees, than the headline percentage applied to a bill with no free units.
- Why doesn't my bill exactly match?
- The actual bill can include arrears, security deposit adjustments or rounding. This calculator shows the energy charge for the units consumed, which is the main part of a domestic bill.
- Does this work for shops or commercial connections?
- No. Commercial (LT-V) and other categories have different rates and fixed charges. This tool covers domestic LT-IA connections only.