Electricity Bill Calculator India

The slab arithmetic

First 100 units: 100 × 3.50 = ₹350
Next 100 units: 100 × 4.50 = ₹450
Remaining 100 units: 100 × 6.50 = ₹650

Energy total = ₹1,450. Add ₹100 fixed charges, then 5% GST on the energy charge (₹72.50): 1,450 + 100 + 72.50 = ₹1,622.50.

Worked examples

100 units → ₹350 + ₹100 + ₹17.50 GST = ₹467.50
150 units → (100 × 3.50) + (50 × 4.50) = ₹575 → ₹703.75 with charges and GST
300 units → ₹1,622.50
500 units → ₹350 + ₹450 + (300 × 6.50) = ₹2,750 → ₹2,987.50
800 units → ₹350 + ₹450 + (600 × 6.50) = ₹4,700 → ₹5,035.00

Slabs are marginal, not flat

The rate on the last unit you use does not apply to all of them. A common mistake is multiplying total units by the top slab rate — 300 × 6.50 would give ₹1,950 and overstate the energy charge by ₹500. Each block is priced on its own, which is why the bill rises faster once you cross into a higher band but never retroactively.

What a real bill adds

• Fixed or demand charges. Payable even at zero consumption, covering the connection and meter.
• Electricity duty. A state levy, often a percentage of the energy charge, on top of GST.
• Fuel surcharge or regulatory surcharge. Adjustable, revised by the regulator, and not part of the slab rate.
• Meter rent and arrears. Small line items that nonetheless appear at the bottom of the bill.
• Subsidy. Some states credit a fixed amount for consumption below a threshold, which can make a large jump between 199 and 200 units.

Use this to check the energy portion adds up, then compare against the tariff sheet for your state and connection type. A domestic and a commercial connection on the same units pay different rates.

Frequently Asked Questions