DEV Community: Shreyash Giri

How to settle group expenses with the fewest payments

Shreyash Giri — Thu, 05 Nov 2026 13:53:49 +0000

Six friends, forty expenses, and everyone owes everyone. It looks like it needs thirty payments. It never needs more than five. Here’s why, and how to do it by hand.

The key idea: only your net balance matters

It doesn’t matter who you owe for each expense; what matters is your total. For each person, add up everything they paid and subtract their share of everything. The result is their net balance:

Positive: the group owes them (they paid more than their share).
Negative: they owe the group.
Zero: they’re square.

The net balances always add up to zero, because every rupee someone paid is a rupee of somebody’s share.

Step 1: Work out each person’s net balance

A four-person Goa trip:

Person	Paid	Share	Net
Aman	₹12,000 (villa)	₹9,000	+₹3,000
Riya	₹10,000 (scooters, food)	₹9,000	+₹1,000
Kabir	₹6,500 (petrol, drinks)	₹9,000	−₹2,500
Neha	₹7,500 (cabs, dinner)	₹9,000	−₹1,500
Total			₹0

Step 2: Match the biggest debtor with the biggest creditor

Kabir owes the most (₹2,500). Aman is owed the most (₹3,000). Kabir pays Aman ₹2,500. Kabir is now square; Aman is still owed ₹500.
Neha owes ₹1,500. Aman is owed ₹500: Neha pays Aman ₹500. Aman is square.
Neha still owes ₹1,000, and Riya is owed ₹1,000: Neha pays Riya ₹1,000. Everyone is square.

Three payments instead of the dozen you’d get by settling each expense separately.

Why it’s never more than n − 1 payments

Each payment in step 2 brings at least one person to zero. With n people, after n − 1 payments only one person can be left, and their balance must be zero because the total is zero. So a 10-person trip never needs more than 9 payments, and usually fewer.

Does simplifying change what anyone pays?

No. Everyone ends with exactly the same net amount. The only thing that changes is who pays whom. In the example, Kabir never directly owed Aman for anything specific, but paying Aman settles his debt to the group just as well.

When people prefer not to simplify

Sometimes people would rather pay the person they actually owe, for example if two people in the group don’t know each other well. That’s fine: settle pair by pair. It just takes more payments.

Practical tips for settling a trip

Settle within a week. Memories fade fast and people move on to the next trip.
Round to the nearest ₹10. Nobody wants to send ₹1,243.50.
Use payment requests. A UPI QR or link with the exact amount means nobody types a wrong number. See UPI tips.
Post the plan in the group chat so everyone can see who pays whom.

Let ttmm do it

ttmm keeps everyone’s net balance live as expenses are added and shows the simplified plan on the group screen. Tap Settle up and it opens your UPI app with the person and amount filled in. See settling up in ttmm.

Questions

What is debt simplification?

Replacing many small IOUs with the fewest payments that leave everyone with the same final balance.

Does simplifying change what anyone pays in total?

No. Everyone’s net amount stays the same; only the number of payments goes down.

How many payments does a group need to settle?

At most one fewer than the number of people with a non-zero balance.

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.

How to split the electricity bill between roommates

Shreyash Giri — Thu, 05 Nov 2026 05:54:41 +0000

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.

How to budget and split a group trip

Shreyash Giri — Wed, 04 Nov 2026 18:51:07 +0000

Group trips are where friendships get tested: someone books the villa, someone else always pays for drinks, and three weeks later nobody can work out who owes what. Here’s how to plan the money so the trip stays fun.

Before the trip

1. Agree a rough budget per person

Before anyone books, agree on a range: “₹12,000–15,000 each, excluding flights”. It saves the awkward moment when one person wants a ₹40,000 villa and another was thinking of hostels.

A simple trip budget has four parts:

Part	Examples	Split
Travel	Flights, trains, cabs to the airport	Usually personal
Stay	Villa, hotel, hostel	Equal, or by room
Local transport	Scooters, taxis, petrol	Equal among those who use it
Food & activities	Meals, drinks, entry tickets, scuba	Equal, or only who joined

2. Collect an advance for bookings

The person who books the stay shouldn’t carry ₹50,000 on their card for a month. Collect each person’s share of the booking before paying. If someone drops out, the rule should be clear: non-refundable bookings are still owed, unless someone takes their place.

3. Make the group before you go

Create a trip group in ttmm and add everyone. Add the advance bookings as soon as they’re paid. You start the trip already knowing the balances.

During the trip

Add every expense when it’s paid, especially cash. A 10-second habit saves a 2-hour argument.
Split only between who was there. The three who went scuba diving split the scuba; the two who skipped the club don’t pay for the club.
Foreign trip? Add expenses in the local currency; ttmm converts at the day’s rate. See trips and currency.
Use a kitty for small cash expenses (tips, chai, parking): everyone puts ₹1,000 in, one person spends from it, and you split what’s left at the end.

Cancellations and changes

Agree the rules before booking:

If someone cancels: they owe their share of anything already paid and non-refundable.
If the whole trip is cancelled: refunds are split the same way as the payment, minus any cancellation fees, shared equally.
If someone joins late: they pay their share of shared costs for the days they’re there (prorate the stay by nights).

After the trip

Settle within a week. Work out everyone’s net balance (paid minus share) and use the fewest payments to square up, which our guide on settling group expenses explains. A six-person trip usually settles in five payments or fewer. ttmm shows the plan and opens UPI for each payment.

A one-minute trip money checklist

Budget range agreed
Advance collected before booking
Cancellation rule agreed
Trip group created, bookings added
Every expense added on the day
Settled within a week

Questions

How do you split a group trip fairly?

Split shared costs (stay, local transport) equally, split activities only among those who joined, and keep travel personal. Settle with the fewest payments at the end.

What if someone cancels a group trip?

They should pay their share of anything already non-refundable, unless someone takes their place.

Should we use a kitty on a trip?

A small cash kitty works well for tips and small cash costs. Track bigger expenses individually.

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.

How to split rent fairly by room size

Shreyash Giri — Wed, 04 Nov 2026 18:34:09 +0000

When one bedroom is bigger, has an attached bathroom or gets the balcony, splitting rent equally quietly annoys someone every month. Here’s a method most flats can agree on in ten minutes, with a full worked example.

Why equal rent often isn’t fair

In most Indian flats the bedrooms are not the same. The master bedroom is usually 30–50% bigger, often has the only attached bathroom, and sometimes the balcony. The third bedroom may be next to the kitchen or have no proper window. If three people pay exactly a third each, the person in the smallest room is subsidising the person in the biggest, and they know it. That resentment shows up later in arguments about cleaning, guests and electricity.

At the same time, a lot of what you pay rent for is shared: the hall, the kitchen, the common bathroom, the parking, the location. Nobody should pay double just because their room is a bit bigger. A fair split has to respect both facts.

The method: shared part + room part + extras

Decide the shared percentage. Take part of the rent for the shared spaces and split it equally. Most flats pick between 30% and 50%. Use more if the hall and kitchen are big and used a lot, less if people mostly stay in their rooms.
Split the rest by bedroom area. Measure each bedroom (length × width in feet is enough) and split the remaining rent in proportion to the area.
Add premiums for real extras. An attached bathroom, a private balcony, a built-in wardrobe or an AC that came with the flat. Agree a fixed rupee amount for each, add it to that room, and take the same total off the others equally.
Round and check. Round to the nearest ₹50 and make sure the shares add up to the full rent.

Worked example: a 3BHK at ₹45,000 a month

Room	Size	Extras
A (master)	12 × 13.3 ft ≈ 160 sq ft	Attached bathroom
B	10 × 12 ft = 120 sq ft	None
C	10 × 12 ft = 120 sq ft	None

Step 1. Shared part (40%): 40% of ₹45,000 = ₹18,000, split equally: ₹6,000 each.

Step 2. Room part (60%): ₹27,000 split by area. The total bedroom area is 400 sq ft, so A has 40%, B 30% and C 30%. A gets ₹10,800, B ₹8,100 and C ₹8,100.

Step 3. Attached bathroom premium: the flat agrees it’s worth ₹1,500 a month. A pays ₹1,500 more; B and C each pay ₹750 less.

Room	Shared	By area	Premium	Total
A	₹6,000	₹10,800	+₹1,500	₹18,300
B	₹6,000	₹8,100	−₹750	₹13,350
C	₹6,000	₹8,100	−₹750	₹13,350
Total				₹45,000

A pays about 40% of the rent for a room that’s 40% of the bedroom space plus the only private bathroom; B and C pay about 30% each. Most people look at that table and agree it’s fair, which is the whole point. Try your own numbers in the rent split calculator.

How big should a premium be?

There’s no official number, so use a market test: what would this extra cost if you rented it separately? Some rules of thumb that flats use:

Attached bathroom: 5–10% of one person’s share. Not having to queue for a bathroom every morning is worth real money.
Private balcony: 3–5% of one share.
AC provided by the landlord: some flats add a premium; others leave it out of rent and handle it through the electricity bill instead. Don’t charge for it twice.
A room with no window or next to the kitchen: a discount works the same way as a premium, in the other direction.

Couples and shared rooms

If a couple shares one bedroom, the room part is per room, but the shared part is usually per person: they use the kitchen, hall and bathroom twice as much as a single person. In our example, if B were a couple, you might split the shared ₹18,000 four ways (₹4,500 per person) and leave the room part per room. Agree on it before moving in; it’s much harder to change later.

When someone leaves

When a flatmate moves out, the person who takes their room usually takes over their share as it is. If nobody replaces them and the remaining flatmates cover the rent, recalculate with the empty room’s area split equally until someone moves in. For half-month stays, see prorated rent.

Set it up once in ttmm

Add rent as a recurring monthly bill in your flat’s group and choose Amounts with the shares from your table. ttmm adds it every month with the same split, so nobody has to remember or recalculate. See recurring bills.

Questions

Should the bigger room pay more rent?

Usually yes. Split part of the rent equally for shared spaces and the rest by bedroom area. That way the bigger room pays more, but not double.

What premium is fair for an attached bathroom?

Many flats use 5–10% of one person’s share. The best test is what the flat would cost without that bathroom.

What percentage should be shared?

Most flats use 30–50%. Use more when the hall and kitchen are big and used a lot.

Is it fair to split rent equally?

Yes, when the rooms are about the same. When they differ, a shared + area split avoids resentment.

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.