In winter nobody cares about the electricity bill. In May, when one flatmate runs the AC all night and the bill triples, everybody does. Here are three fair methods and how to pick one.
First, understand your bill
Indian electricity bills have two parts. The fixed charge depends on your sanctioned load and doesn’t change much month to month. The energy charge is the units (kWh) you used multiplied by a per-unit rate. In most states the rate goes up in slabs: the first units are cheap, the next ones cost more. That’s why a bill can triple when usage only doubles: the extra units land in the most expensive slab. Your bill shows your units, your slabs and the rates. Look at it once; it makes the rest of this guide easy.
Method 1: Split equally
Best when: everyone has similar appliances, nobody runs an AC or room heater much, or the differences are small.
It’s the simplest and causes the fewest arguments. If the difference between people is ₹100–200 a month, an equal split is usually worth the peace. Fridge, lights, fans, WiFi router, geyser and washing machine are shared anyway.
Method 2: Base + usage (the fairest for AC season)
Best when: one or two people use an AC, a room heater or a gaming PC a lot more than others.
- Find the base. Use a month when nobody ran the AC (usually December–February). That bill is your base: what the flat costs to run without the heavy appliances.
- Split the base equally.
- Split the extra by usage. The extra is this month’s bill minus the base. Split it between the people who caused it, equally or by hours of use.
Example. The May bill is ₹4,800 and a typical January bill is ₹1,800. There are three flatmates; A and B have ACs, C doesn’t.
| A (AC) | B (AC) | C (no AC) | |
|---|---|---|---|
| Base ₹1,800 ÷ 3 | ₹600 | ₹600 | ₹600 |
| Extra ₹3,000 ÷ 2 | ₹1,500 | ₹1,500 | — |
| Total | ₹2,100 | ₹2,100 | ₹600 |
If A runs the AC every night and B only on weekends, split the extra by hours instead (say 70:30). Our electricity split calculator does both.
Estimating how much an AC uses
If there’s no clean base month, estimate the AC’s share directly:
AC cost ≈ hours used × units per hour × rate per unit
- A 1.5-ton split AC typically draws about 1.2–1.8 units an hour. Inverter ACs use less once the room is cool; older non-inverter ACs use more. The star-rating sticker on the AC lists its yearly energy use.
- Your rate per unit is on your bill. For the top slab it’s often ₹6–10 depending on the state.
Example: 8 hours a night × 30 nights × 1.4 units × ₹8 ≈ ₹2,690 a month. That person pays it, plus their equal share of the rest.
Method 3: Sub-meters
Best when: each room has its own sub-meter (common in PGs and some newer flats).
Note each sub-meter reading on the bill date. Each person pays their own units × the average rate (total energy charge ÷ total units), and the common area (the main reading minus all the sub-meters) plus the fixed charge are split equally. It’s the most accurate method, but someone has to read the meters every month. Put it on the chore wheel.
Which method should your flat use?
| Situation | Method |
|---|---|
| No ACs, similar usage | Equal |
| One or two ACs, no sub-meters | Base + usage |
| Sub-meter in every room | Sub-meters |
| Mixed: AC only in summer | Equal Oct–Feb, base + usage Mar–Sep |
Prepaid meters and late fees
With a prepaid meter, treat each recharge as an expense and split it with the same method. Late-payment surcharges should be paid by whoever was supposed to pay the bill on time. Agree that in advance (see our flatmate money rules).
In ttmm
Add the bill as an expense. For base + usage, use Amounts with the numbers from the calculator, or Shares (7:7:2 is the example above). If you split it the same way every month, make it a recurring bill and just update the amount.
Questions
Is it fair to split electricity equally between roommates?
It’s fair when usage is similar. If one person runs an AC or heater a lot more, a base + usage split is fairer.
How do I calculate AC electricity cost?
Multiply hours of use × units per hour (about 1.2–1.8 for a 1.5-ton AC) × your per-unit rate from the bill.
Why did our bill triple when usage only doubled?
Most Indian tariffs use slabs: extra units are charged at the highest rate, so cost rises faster than usage.
Who pays the fixed charge?
Split it equally. It doesn’t depend on who used what.
Originally published on ttmmsplit.in. ttmm is a free bill-splitting app for flatmates, trips and friends — settle up on UPI in one tap. Try it free.
Top comments (0)