TNEB bill calculator 2026, with solar savings.
Enter the units on your bi-monthly bill to see your TNPDCL (TANGEDCO) charge under the 2026 slabs, then see what rooftop solar would save.
Tamil Nadu domestic electricity is billed every two months on a telescopic slab tariff. Since May 2026 the first 200 units are free if you use 500 units or less in the cycle; above 500 units only 100 units are free. Type your units below to calculate the bill, and see how much a rooftop solar system would cut it after the PM Surya Ghar subsidy.
- TNEB bill
- 200 free units
- 2026 slab rates
- Solar savings
- PM Surya Ghar
- Payback
TNEB bill calculator with solar savings
- Your current bill (energy charge)
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- Bill with rooftop solar
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- You save
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- System price after subsidy (central + Tamil Nadu)
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- Payback
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You are just above 500 units. Above 500 you lose 100 of the 200 free units, so a small solar system that brings you under 500 cuts the bill sharply.
Energy charges only, using the 2026 domestic (LT-IA) slab rates below; fixed charges are not included. Solar assumes about 120 units per kW per month, units used at home cut your bill at slab rates, and surplus is credited at ₹3.61/unit (TNERC net feed-in, conservative). Prices are indicative midpoints for DCR on-grid systems including GST. Subsidy includes the Tamil Nadu top-up (₹5,000 / ₹10,000 / ₹22,000), which applies only to PM Surya Ghar registrations from 5 August 2026. For a shop, office or factory use the business solar calculator.
TNEB domestic tariff 2026 (bi-monthly)
Rates as of October 2026, per G.O. (Ms) No. 50 (10 May 2026) and TNERC Order No. 5 of 2026. The tariff is telescopic: each rate applies only to the units inside its slab. Check your printed bill if a revision has been notified since.
If you use 500 units or less (200 units free)
| Units (bi-monthly) | ₹ per unit |
|---|---|
| 1–200 | Free |
| 201–400 | ₹4.70 |
| 401–500 | ₹6.30 |
If you use more than 500 units (100 units free)
| Units (bi-monthly) | ₹ per unit |
|---|---|
| 1–100 | Free |
| 101–400 | ₹4.70 |
| 401–500 | ₹6.30 |
| 501–600 | ₹8.40 |
| 601–800 | ₹9.45 |
| 801–1000 | ₹10.50 |
| Above 1000 | ₹11.55 |
Worked examples
| Bi-monthly units | How it is calculated | Energy charge |
|---|---|---|
| 300 | 200 free + 100 × ₹4.70 | ₹470 |
| 500 | 200 free + 200 × ₹4.70 + 100 × ₹6.30 | ₹1,570 |
| 501 | 100 free + 300 × ₹4.70 + 100 × ₹6.30 + 1 × ₹8.40 | ₹2,048 |
| 600 | 100 free + 300 × ₹4.70 + 100 × ₹6.30 + 100 × ₹8.40 | ₹2,880 |
| 1,000 | … + 200 × ₹9.45 + 200 × ₹10.50 | ₹6,870 |
One unit over 500 adds about ₹478 to the bill because the free units drop from 200 to 100. Households just above 500 units gain the most from even a small rooftop system.
How much solar do you need?
- Each 1 kW of rooftop solar makes about 240 units per bi-monthly bill (120 a month).
- 500–600 units per bill: 2–3 kW, ₹60,000–78,000 subsidy.
- 800–1,000 units: 3–4 kW. 1,200+ units: 5 kW or more.
- You need about 90–100 sq ft of shade-free roof per kW.
- Prices and sizes: home rooftop solar · Subsidy steps: PM Surya Ghar guide · More ways to cut the bill: reduce your electricity bill.
Why Goggles Energy
One engineering team from feasibility to O&M. A real engineer reviews every enquiry, models CAPEX, RESCO and open access against your actual bills, and handles TNPDCL (TANGEDCO) approvals end to end. Offices in Nagercoil (HQ) and Chennai.
FAQ
How is the TNEB bill calculated in 2026?
Domestic bills are bi-monthly and telescopic. If you use 500 units or less, the first 200 units are free, 201–400 cost ₹4.70 and 401–500 cost ₹6.30 per unit. Above 500 units only 100 units are free, and higher slabs of ₹8.40, ₹9.45, ₹10.50 and ₹11.55 apply. Fixed charges are added separately.
What is the TNEB bill for 500 units?
About ₹1,570 in energy charges: 200 units free, 200 units at ₹4.70 and 100 units at ₹6.30.
What is the TNEB bill for 600 units?
About ₹2,880: 100 units free, 300 at ₹4.70, 100 at ₹6.30 and 100 at ₹8.40. Crossing 500 units removes 100 free units.
Are 200 units free in Tamil Nadu?
Yes, from May 2026, for households using up to 500 units in a two-month billing cycle (G.O. Ms No. 50). Above 500 units, 100 units are free.
How much will rooftop solar save on my TNEB bill?
Each kW makes about 240 units per bill. A 3 kW system can bring a 600-unit bill from about ₹2,880 to near zero. Use the calculator above with your own units, then get an exact quote.
Which company installs rooftop solar to cut TNEB bills?
Goggles Energy designs and installs home, commercial and industrial rooftop solar across Tamil Nadu, handles the PM Surya Ghar subsidy paperwork and TNPDCL net metering, and has built 150+ MW since 2013.