ElectroHub

Electricity Bill Calculator (Slabs)

Indian domestic tariffs are telescopic: crossing into a higher slab only raises the rate on the units above the boundary, not on all of them. Most quick calculators charge everything at the top rate and over-state the bill. Both methods are worked out here so the difference is visible.

Electricity bill (slab tariff)

Indian domestic tariffs are telescopic: cross into a higher slab and only the units above the boundary pay the higher rate — the ones below stay where they were. Most quick calculators get this wrong and charge every unit at the top rate. Both are worked out here so you can see the difference.

Energy charge
Fixed charge
Duty / tax
Total bill
Average rate
Billed the other way
SlabUnits₹/unitAmount
0–50504₹200
50–100505.5₹275
100–2001007₹700
200–240408₹320
  • Telescopic billing: each slab charged at its own rate. Charging all 240 units at the top rate of ₹8 would give ₹2392.80 instead — that difference is what "telescopic" is worth to you.
A neutral example so the calculator works out of the box. Replace every rate with the ones printed on your bill.
Common trap: Tariffs are revised every year and differ by state, consumer category and sanctioned load. The arithmetic here is exact whatever rates you enter — the rates themselves have to come off your own bill.

The formula

Bill = Σ(units in each slab × that slab's rate) + fixed charge × sanctioned kW + duty

units
consumption in kWh — one 'unit' on a bill is one kWh
slab rate
₹ per unit for the band, applied only to units inside it
fixed charge
₹ per kW of sanctioned load, payable whatever you use
duty
electricity duty or tax, a percentage of the energy charge

Worked example

240 units on a 50 / 100 / 200 / above tariff at ₹4.00, ₹5.50, ₹7.00, ₹8.00, with 3 kW sanctioned at ₹100/kW and 9 % duty.

  1. First 50 units × ₹4.00 = ₹200
  2. Next 50 units × ₹5.50 = ₹275
  3. Next 100 units × ₹7.00 = ₹700
  4. Last 40 units × ₹8.00 = ₹320
  5. Energy charge = ₹1495 ; fixed = 3 × 100 = ₹300 ; duty = 9 % of 1495 = ₹134.55

₹1929.55. Charging all 240 units at ₹8.00 would give ₹2392.80 — that gap is what telescopic billing is worth.

Where you'll use it

Checking a bill that looks wrong, working out what an air conditioner will actually cost to run, and seeing how close you are to the next slab boundary. Tariffs change every year and differ by state and consumer category, so the rates have to come off your own bill — the arithmetic here is exact whatever you enter.

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