Estimate your Tamil Nadu electricity bill from the units on your meter, slab by slab.
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How TNEB (TANGEDCO) bills are calculated
Tamil Nadu domestic bills are raised every two months. The first 100 units are free. Which slab table applies depends on your total bi-monthly consumption: up to 500 units you pay ₹2.35 for units 101–200, ₹4.70 for 201–400 and ₹6.30 for 401–500; above 500 units the 101–400 band is charged at ₹4.70, then ₹6.30 (401–500), ₹8.40 (501–600), ₹9.45 (601–800), ₹10.50 (801–1000) and ₹11.55 beyond 1000.
Example: 420 units → 100 free + 100 × 2.35 + 200 × 4.70 + 20 × 6.30 = ₹1,301. The same 420 units in a month with 520 total would cost more because the higher table applies.
Rates are revised every July by the Tamil Nadu Electricity Regulatory Commission (the figures above are the LT-1A domestic tariff schedule adopted in July 2024). Open "Edit slab rates" to enter the rates printed on your latest bill — the calculator then matches it exactly.
Reduce your EB bill
- Staying under 500 units per 2 months keeps you on the cheaper table.
- A 5-star inverter AC uses ~0.8–1 unit per hour; a ceiling fan 0.07; a geyser 2 units per hour.
- Check meter readings at tnebnet.org and pay online to avoid late fees.
Sources & last reviewed
Tamil Nadu domestic (LT I-A) tariff as per the Tamil Nadu Electricity Regulatory Commission (TNERC) tariff order and its annual revision; 100 free units per bi-monthly bill under the state scheme. Slab rates are editable above because TNERC revises them each July — check your latest bill.
Official sources: TNERC · TNPDCL / TANGEDCO
Last reviewed: 17 October 2026. Rules and rates change — if you spot something outdated, tell us and we will fix it.
Frequently asked questions
How many free units does TNEB give?
100 units every two months (bi-monthly billing) for domestic connections, under the state government's scheme.
What is the TNEB rate per unit for 500 units?
For a bi-monthly total of exactly 500 units: 100 free, 100 units at ₹2.35, 200 at ₹4.70 and 100 at ₹6.30 — ₹1,805 in energy charges, i.e. an average of about ₹3.61 per unit.
Why did my bill jump when I crossed 500 units?
Above 500 units the entire 101–400 band is charged at ₹4.70 instead of ₹2.35 for the first 100 of them, and the extra units cost ₹8.40 or more — so the whole bill, not just the extra units, becomes dearer.