Split the electricity bill fairly, down to the unit.

Enter each room's meter usage and the total bill. We work out the common usage and split everything the way Tamil Nadu's slab tariff actually charges it.

Start splitting How it works

Bill splitter

Pre-filled with an example. Change anything and results update instantly.

1Rooms and meters

2Bill details

Tariff slabs (Domestic, LA1A)

Edit if the tariff changes. The last slab has no upper limit.

TN bill calculator

Works like the official calculator: enter consumed units, get the slab-wise charges.

How it works

Tamil Nadu bills by slabs: cheap units first, expensive units last. Splitting by plain usage hides that, so we follow the slabs.

1. Find the common usage

Total units come from the bill (we reverse the slab calculation) or from your meter readings. Common = total units − sum of all room sub-meter units.

2. Common + fixed costs on top

Common units are charged at the highest slab reached. Fixed charges and electricity duty are added to this pool. The pool is then split pro-rata by days stayed.

3. Cheap slabs are shared

The cheap slabs below the top one are shared equally between rooms, so nobody gets the whole free or low-rate benefit.

4. Extra units at top rate

Each room pays the top rate only for meter units beyond its equal share of cheap slabs. The room cost is then split by number of people.

The formula

room cost = (cheap slab cost ÷ rooms) + (room units − cheap units ÷ rooms) × top rate per person = room cost ÷ people + (common cost + fixed + duty) × (days/total days) ÷ equiv. people

Example: 2,709 units, 2,273 room and 436 common, bill ₹26,608.95. Common = 436 × 11.55 = ₹5,035.80, split pro-rata among 6 people (full month). Cheap slabs (first 1,000 units) cost ₹6,870, so ₹2,290 per pair. A pair with 535 units pays 2,290 + (535 − 333.33) × 11.55, then splits that two ways and adds their common share.

The shares always add up to exactly the bill. If a room uses fewer units than its equal share of the cheap slabs, the splitter falls back to splitting by usage proportionally and tells you.