TNEB Electricity Bill Calculation Guide & Calculator
If your Tamil Nadu electricity bill suddenly jumped despite using roughly the same amount of power as last month, the slab structure is likely the reason. TANGEDCO (Tamil Nadu Generation and Distribution Corporation, operating under the TNEB brand) uses a tiered rate system where each additional unit you consume is charged at a progressively higher rate.
Understanding how this works takes about five minutes — and it can genuinely help you manage consumption to stay within cheaper tiers.
How TANGEDCO Bills Domestic Consumers
TANGEDCO issues electricity bills on a bi-monthly cycle for most domestic consumers. This means your bill covers approximately 60 days of consumption, not 30. This is an important detail because the slab limits are applied to the full bi-monthly consumption — not to a monthly average.
However, TANGEDCO also provides a monthly equivalent for reference on the bill. For the purposes of this guide, we will use monthly unit consumption for clarity, noting that the actual billing cycle is bi-monthly.
Estimate your TANGEDCO household bill using actual telescopic rules. Note: Slabs are calculated on a bi-monthly (60-day) consumption basis.
The Domestic Tariff Slab Structure (2026)
Tamil Nadu’s domestic electricity tariff uses a **progressive slab system** approved by the Tamil Nadu Electricity Regulatory Commission (TNERC). Lower consumption units are charged at lower rates; consumption beyond a threshold is charged at higher rates.
Unlike standard telescopic bills, TANGEDCO implements a two-tier subsidy structure where your total bi-monthly consumption determines the rate card applicable to your entire bill:
Tier 1: Bi-Monthly Consumption ≤ 500 Units (High Subsidy)
| Consumption Slab (Bi-Monthly) | Approved Rate per Unit (₹) | Effective Cost (With Govt. Subsidy) |
|---|---|---|
| 0–100 units | ₹4.95 | FREE (₹0.00) |
| 101–200 units | ₹4.95 | ₹2.35 |
| 201–400 units | ₹4.95 | ₹4.70 |
| 401–500 units | ₹6.65 | ₹6.30 |
Tier 2: Bi-Monthly Consumption > 500 Units (Low Subsidy)
| Consumption Slab (Bi-Monthly) | Approved Rate per Unit (₹) | Effective Cost (With Govt. Subsidy) |
|---|---|---|
| 0–100 units | ₹4.95 | FREE (₹0.00) |
| 101–400 units | ₹4.95 | ₹4.70 (Subsidy Reduced!) |
| 401–500 units | ₹6.65 | ₹6.30 |
| 501–600 units | ₹8.80 | ₹8.40 |
| 601–800 units | ₹9.95 | ₹9.45 |
| 801–1000 units | ₹11.05 | ₹10.50 |
| Above 1000 units | ₹12.15 | ₹11.55 |
To analyze other utility tariffs and structure maps, utilize our general electricity slab rates explorer tool.
A Worked Example: Calculating a Bill from Scratch
To demonstrate how these tiered electricity slab rates compound, let’s look at how TANGEDCO processes energy charges for a typical household using **350 units** versus a slightly larger household using **550 units**:
Example 1: 350 Units (Tier 1 Rules Apply)
Since 350 units is less than 500 units, the heavily subsidized Tier 1 rate chart applies:
- 0–100 Units: 100 units × ₹0 = ₹0.00
- 101–200 Units: 100 units × ₹2.35 = ₹235.00
- 201–350 Units: 150 units × ₹4.70 = ₹705.00
Total Energy Charge: ₹940.00
Example 2: 550 Units (Tier 2 Rules Apply)
Because the consumption exceeds 500 units, the subsidy on the 101–200 unit slab drops, and rates climb significantly:
- 0–100 Units: 100 units × ₹0 = ₹0.00
- 101–400 Units: 300 units × ₹4.70 = ₹1,410.00 (Note the rate hike)
- 401–500 Units: 100 units × ₹6.30 = ₹630.00
- 501–550 Units: 50 units × ₹8.40 = ₹420.00
Total Energy Charge: ₹2,460.00
Notice how adding 200 extra units didn’t just add a linear cost — it caused the total charge to climb from **₹940 to ₹2,460** because of TANGEDCO’s structural penalties on high-consumption connections.
What Else Is Added to Your Bill?
The unit consumption charge is only part of your total bill. TANGEDCO also adds:
- Fixed Charges: Currently, domestic connections in Tamil Nadu are largely exempt from heavy bi-monthly fixed service charges, prioritizing energy usage penalties instead.
- Electricity Duty (ED): A state levy calculated at 5% of energy charges. For standard domestic households under 500 units, ED is typically exempted, whereas larger commercial users face mandatory additions.
- Meter Rent & Surcharges: Nominal fees for metering equipment and maintaining local grids, including seasonal Fuel Cost Adjustments (FCA) to match coal/generation costs.
For instant and customizable billing estimates that dynamically calculate all of these secondary regulatory additions, use our dedicated online TNEB electricity bill calculator utility.
How to Read Your TANGEDCO Bill
Your physical or digital EB bill contains these key fields:
- Consumer Number: Your unique TANGEDCO account identifier — needed for online payment
- Service Number: Identifies your specific connection (a single consumer may have multiple)
- Previous Reading / Current Reading: The meter values used to calculate consumption
- Units Consumed: Current reading minus previous reading
- Energy Charges: The calculated amount based on slabs
- Fixed Charges / Connected Load: The flat service charge based on your sanctioned load
- Arrears: Any unpaid amount from previous bills
- Net Amount Due: What you owe for this billing period
- Due Date: Pay before this date to avoid late payment charges