You open that SMS from TNEB. The number hits you before you finish reading it. Higher than last time — noticeably higher — and you have no idea why.
Most people in Tamil Nadu know their final bill amount. They do not know how TNEB arrived at it. That gap is exactly what this guide fills.
What is the 1 Unit Electricity Price in Tamil Nadu right now? What are the actual slab rates? And why does crossing one particular number wreck your bill? Let’s get into it — no fluff, just the actual numbers from the official FY 2026-27 TANGEDCO tariff order.
Why TNEB Bills You Once in Two Months
Most Indian states send monthly electricity bills. Tamil Nadu does things differently. Residential consumers are billed once every two months — a bi-monthly cycle. The meter assessor visits your home, records the reading on the White Card, and the cycle resets.
This detail changes everything about how your bill is calculated. When the government says “100 units free per month,” that translates to 200 free units on your bi-monthly bill. Every slab, every subsidy, every calculation you read below is based on your two-month consumption total — not per month.
1 Unit Electricity Price in Tamil Nadu — Domestic Slab Rates (LT-IA)
Here are the exact per-unit rates for all residential consumers under the LT-IA tariff effective from 01 April 2026. Understanding these slabs is the only way to make sense of your TNEB bill.
📊 TNEB Domestic Tariff 2026-27 (LT-IA) — Bi-monthly Rates
| Bi-monthly Units | Rate per Unit | Fixed Charges | Free Unit Rule |
|---|---|---|---|
| 0 – 100 Units | ₹ 0.00 | None | ✅ Free (if total ≤ 500 units) |
| 101 – 200 Units | ₹ 0.00 | None | ✅ Free (if total ≤ 500 units) |
| 201 – 400 Units | ₹ 4.70 | None | Standard domestic rate |
| 401 – 500 Units | ₹ 6.30 | None | Upper standard tier |
| 501 – 600 Units ⚠️ | ₹ 8.40 | None | Only 100 units free now |
| 601 – 800 Units | ₹ 9.45 | None | Premium tier |
| 801 – 1000 Units | ₹ 10.50 | None | High usage tier |
| Above 1000 Units | ₹ 11.55 | None | Peak residential rate |
Source: TANGEDCO Tariff Order FY 2026-27 | No fixed charges apply for domestic LT-IA connections.
🔵 Important: The green rows (0–200 units) are completely free only when your total bi-monthly consumption is 500 units or less. Cross that line and TNEB changes the rules — only the first 100 units remain free.
The 500-Unit Catch — Why Your Bill Can Nearly Double
This is the detail that catches thousands of Tamil Nadu households off guard every billing cycle. The TNEB subsidy system rewards low-to-medium consumers but penalises heavier users sharply.
If your total two-month consumption is 500 units or below, TNEB credits you 200 units for free. Your bill only covers the remaining units at the subsidised slab rates. Life is manageable.
Cross 501 units — even by a single unit — and two things happen at once. Your free unit credit drops from 200 to just 100 units. And the rates for higher slabs kick in starting at ₹8.40 per unit. Both hit your bill simultaneously.
Here is what that looks like in actual rupees:
✅ Scenario A — 490 Units
Total ≤ 500 → 200 units FREE
| Units 0 – 200 | ₹ 0.00 (Free) |
| Units 201 – 400 | ₹4.70 × 200 = ₹940 |
| Units 401 – 490 | ₹6.30 × 90 = ₹567 |
| Total Bill | ≈ ₹1,507 |
⚠️ Scenario B — 510 Units
Total > 500 → Only 100 units FREE
| Units 0 – 100 | ₹ 0.00 (Free) |
| Units 101 – 200 | ₹2.35 × 100 = ₹235 |
| Units 201 – 400 | ₹4.70 × 200 = ₹940 |
| Units 401 – 500 | ₹6.30 × 100 = ₹630 |
| Units 501 – 510 | ₹8.40 × 10 = ₹84 |
| Total Bill | ≈ ₹1,889 |
Those extra 20 units cost ₹382 more. That works out to nearly ₹19 per unit just for that extra band of consumption. This is why checking your meter reading 10 days before the assessor visits is not optional — it is the smartest thing a domestic TNEB consumer can do.
To calculate your exact bill based on your actual unit consumption, use the Tamil Nadu electricity bill calculator — it handles all the bi-monthly slab rules and subsidy changes automatically.
Commercial and Industrial Unit Prices (No Subsidies)
Non-residential connections work on a completely different logic. No free units. No slabs. You pay a flat rate from unit one, plus monthly fixed charges based on your sanctioned load in kilowatts — whether you use that capacity or not.
Shops and Offices — LT-V (Commercial General)
Energy Charge
₹8.80 / unit
Flat rate, no slabs
Fixed Charge
₹221 / kW / month
Per kW sanctioned load
Example: A shop with 5 kW sanctioned load pays ₹1,105 in fixed charges every month — even if the shop was closed and consumed zero units.
Cottage and Small Industries — LT-III A1
0 – 500 Units
₹4.95 / unit
Above 500 Units
₹7.15 / unit
No fixed charges apply for cottage and micro-industry connections.
Power Looms — LT-III A2
0 – 1000 Units
FREE
1001 – 1500 Units
₹4.60
Above 1500 Units
₹5.85
Fixed charges of ₹110/kW/month apply only when bi-monthly consumption exceeds 1500 units.
EV Charging Stations — LT-VI
Energy Charge
₹8.50 / unit
Fixed Charge
₹315 / kW / month
⚡ Skip the Manual Math
TNEB’s slab system — especially the 500-unit subsidy cliff — is genuinely complicated to calculate by hand. Our free interactive tool handles all the bi-monthly slab math, subsidy rules, and fixed charge calculations in seconds.
Single-Phase vs Three-Phase — Does Your Meter Type Change the Rate?
No. For domestic LT-IA connections, the per-unit rates and slab structure are identical for single-phase and three-phase meters. Your meter type does not change your 1 Unit Electricity Price in Tamil Nadu. A three-phase connection handles heavier loads more safely — it does not attract a different tariff category.
How to Keep Your TNEB Bill Below the 500-Unit Line
| Action | Estimated Saving | Risk if Skipped |
|---|---|---|
| Set AC thermostat to 24°C instead of 20°C | ~6% energy saving per degree raised | Compressor runs longer, units stack up fast |
| Check your meter reading 10 days before the assessor visit | Lets you cut usage if near 500-unit mark | Cannot undo a 501-unit reading after assessor visits |
| Switch to BLDC ceiling fans (28W–35W) | Saves 40–50 units bi-monthly vs old 75W fans | Old fans add visible consumption over two months |
| Unplug televisions and set-top boxes at night | Eliminates 5–8 units of standby draw per month | Devices on standby draw power continuously |
Two TNEB Myths That Will Not Die
Myth 1: “Switch off your main switch for one hour to reset the digital meter.”
This circulates constantly on WhatsApp. It is completely false. TNEB digital meters use non-volatile solid-state memory. Cutting power to your home does not touch the meter’s internal register. The only thing this achieves is turning off your appliances for an hour.
Myth 2: “The assessor delays the reading on purpose to push you into a higher slab.”
Administrative delays do occur. But TNEB’s billing software uses a normalisation algorithm that adjusts for reading cycles longer than the standard 60-day window. If you believe a delay has genuinely inflated your bill, you have the right to request a formal bill review at your local TNEB section office with the Assistant Executive Engineer (AEE).
Disclaimer: The tariff rates, slabs, and rules mentioned in this article are based on official TANGEDCO notifications for FY 2026-27 and are subject to revision. Please consult your latest official TNEB bill or your local division office for verified dispute resolution.
Frequently Asked Questions
What is the 1 unit electricity price in Tamil Nadu for home connections?
There is no single flat rate for domestic consumers. TNEB uses a tiered slab system under the LT-IA category. The first 200 units per bi-monthly cycle are free (if total consumption is ≤ 500 units). Beyond that, rates range from ₹4.70 to ₹11.55 per unit depending on total two-month consumption.
How does the 200 free units scheme actually work in Tamil Nadu?
Tamil Nadu bills residential consumers every two months. The state government’s “100 units free per month” subsidy adds up to 200 free units over a bi-monthly billing cycle. But this full 200-unit credit is only available when your total bi-monthly consumption stays at or below 500 units. Cross that threshold and the free credit drops to 100 units.
Why does my TNEB bill jump so much after crossing 500 units?
Crossing 500 units triggers two simultaneous changes: your free unit benefit drops from 200 units to 100 units, and units above 500 are billed at premium rates starting at ₹8.40 per unit. Both changes compound together, which is why even a small increase near the 500-unit mark can produce a disproportionately large bill increase.
Do commercial TNEB connections get any free units?
No. Commercial connections under LT-V are charged a flat ₹8.80 per unit from the very first unit with no free unit subsidy. They also pay monthly fixed charges of ₹221 per kW of sanctioned load, regardless of how many units were actually consumed that month.
Is the TNEB unit price the same for single-phase and three-phase domestic meters?
Yes. Under the LT-IA domestic tariff, the per-unit rate and slab structure are identical for both single-phase and three-phase residential connections. The phase type affects load capacity, not your tariff category or per-unit charge.
How do I check my TNEB consumer number?
Your 12-digit consumer number is printed on the White Card the assessor fills during meter readings. It is also available on printed TNEB bills, SMS payment reminders, and on the TANGEDCO web portal if you have a registered account.
What happens if I miss my TNEB bill due date?
TNEB levies a late payment surcharge on overdue amounts. Beyond the surcharge, if the bill remains unpaid past the grace period, the local EB section office can initiate a power disconnection order. Reconnection after disconnection involves an additional fee.
Can I apply for a meter test if I think my TNEB meter is running fast?
Yes. Apply for a meter accuracy test at your local TNEB section office by paying a nominal fee. TNEB installs a parallel check meter to compare readings. If the original meter is found faulty, TNEB replaces it at no cost and revises your previous bills accordingly.
How does TNEB solar net metering work for home consumers?
Under TNEB’s net metering scheme, the units your rooftop solar panels export to the grid are subtracted from the units your home imports. Your bi-monthly bill is based on this net consumption figure. If your export exceeds your import, surplus units are carried forward as a credit to the next billing cycle.
How are electricity charges for apartment common areas calculated?
Common area connections (lifts, water pumps, corridor lighting) in apartment complexes are billed under a separate commercial or general services connection — not under the domestic LT-IA category. This means no residential free unit subsidies apply, and fixed charges are based on the sanctioned load of that shared connection.
Official Resource: For further details on tariff orders, visit the TANGEDCO Official Website.
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