Tamil Nadu Electricity Tariff Rates & Charges

Tamil Nadu 1 Unit Rate

For domestic electricity consumers in Tamil Nadu, the initial 1 unit rate starts at ₹4.70 per kWh for consumption within the first slab per bi-monthly billing cycle.

Tariff Categories

The tariff schedule for Tamil Nadu covers 4 consumer categories:

• Domestic (Residential) — for households.
• Commercial — for shops and businesses.
• Industrial — for factories and manufacturing units.
• Agriculture — for irrigation and farm-pump connections.

Fixed Charges and Other Charges

On top of unit energy rates, TNEB bills can include:

• A fixed or demand charge, based on connection parameters.
• Meter rent, where applicable.

Electricity Bill Calculation

To estimate your Tamil Nadu electricity bill by hand:

1. Multiply your bi-monthly consumption in kilowatt-hours (units) by the applicable slab rate for each band.
2. Add the fixed or demand charge.
3. Add electricity duty and any fuel cost adjustment that applies.

Or skip the arithmetic with our TNEB electricity bill calculator.

Why the rate is not one number

TNEB's domestic tariff is telescopic: each unit you consume is billed at the rate of the slab it falls into, not a single rate applied to your whole bill. Your rate rises from ₹4.70/unit at the first slab to ₹11.55/unit at the top — so your 50th unit and your 400th unit genuinely cost different amounts, and a bigger household does not just pay “more of the same rate”, it pays a higher rate on the extra units.

How TNEB's categories compare

The same unit of electricity is not priced the same for every connection type. On TNEB, the first-slab domestic rate is ₹4.70/unit, compared with:

• Commercial starts at ₹6.65/unit at its first slab — ₹1.95 higher than domestic.
• Industrial starts at ₹8.25/unit (flat, all units) — ₹3.55 higher than domestic.
• Agriculture starts at ₹0.00/unit (flat, all units) — ₹4.70 lower than domestic.

Commercial and industrial rates are usually higher because they are not subject to the same cross-subsidy that keeps small domestic consumption affordable; agricultural rates are frequently subsidised the other direction. Each category's full slab table is above.

Worked example: a 200-unit bi-monthly bill

For a domestic connection on TNEB consuming 200 units in one bi-monthly billing period, with a 2 kW sanctioned load:

• Energy charge (slab-wise): ₹940.00
• Fixed charge (flat): ₹0.00
• Total: ₹0.00

That works out to ₹0.00 per unit on average — higher than the ₹4.70 first-slab rate, because the fixed charge and duty are spread across the bill. A different sanctioned load changes the fixed-charge line above.

Getting your connection category right

The category your connection is registered under — not how the premises is actually used — is what the DISCOM bills against. A few situations that catch people out:

• A shop, home office, or any space used for business is normally billed as Commercial, not domestic, even if it shares a building with your residence.
• The Agriculture category applies to irrigation and farm-pump connections specifically, generally subject to its own eligibility and sanctioned-load rules rather than a household's domestic connection.
• Changing a connection's registered category, or its sanctioned load, is a request you make to TNEB directly — this page and our calculator both price whichever category and load you select, they do not change what is on file with the DISCOM.

How often these rates change

This tariff schedule took effect 10 May 2026 and we last verified it on 10 October 2026. Slab rates and fixed charges typically move once a year or less, set by Tamil Nadu's electricity regulatory commission in a tariff order; where a fuel cost adjustment applies it is usually revised more often than the slab rates themselves.

Before relying on these figures for a large or binding decision, check TNEB's own published schedule:

TNEB's tariff source →

Average rate versus marginal rate

The average rate in the worked example above is what your whole bill costs per unit. It is the wrong number for one decision: whether to run one more appliance. Because the tariff is telescopic, any extra unit you add lands on your top slab, not your average — see our TNEB unit price page for that marginal figure and how it compares with the average.