Splitting a restaurant bill with tax and tip, exactly
Why you split the subtotal first and scale the tax, and how to do the whole thing before the card machine arrives.
3 min read
The bill arrives, someone says "shall we just split it four ways?", and the person who had soup and water says "sure". That's the moment the ledger goes quietly wrong. Here's the fair way, and it takes one multiplication.
The bill
Dinner for four
Saturday
- Food and drinks (subtotal)
- ₹3,240.00
- GST at 5%
- ₹162.00
- Tip at 10% of subtotal
- ₹324.00
Total to pay
₹3,726.00
Four people, four very different appetites. What each person actually ordered, before tax and tip:
Who ordered what
subtotal only
- You
- ₹1,020.00
- Priya
- ₹640.00
- Arjun
- ₹980.00
- Sam
- ₹600.00
Matches the subtotal
₹3,240.00
Scale, don't itemise
You don't need to work out the tax on each dish. Tax and tip are both proportional to the subtotal, so everyone's share grows by the same factor:
₹3,726.00 ÷ ₹3,240.00 = 1.15, so every subtotal share is multiplied by 1.15.
Final shares
subtotal × 1.15
- You₹1,020.00 × 1.15
- ₹1,173.00
- Priya₹640.00 × 1.15
- ₹736.00
- Arjun₹980.00 × 1.15
- ₹1,127.00
- Sam₹600.00 × 1.15
- ₹690.00
Adds up exactly
₹3,726.00
In SplitPocket, that's one expense of ₹3,726.00 split by exact amounts. Type the four numbers; the app refuses to save until they add up to the total, which is exactly the check you want at 11pm.
What the lazy split costs
An equal four-way split of ₹3,726.00 is ₹931.50 each. Compare that to the fair shares:
Equal split vs fair split
difference per person
- You₹931.50 instead of ₹1,173.00
- −₹241.50
- Priya₹931.50 instead of ₹736.00
- +₹195.50
- Arjun₹931.50 instead of ₹1,127.00
- −₹195.50
- Sam₹931.50 instead of ₹690.00
- +₹241.50
The cases that need a second line
- Shared starters. Add the plates you genuinely shared into a separate equal split, and keep individual orders on the exact-amounts line. Two expenses is fine. Two expenses is honest.
- Drinks when half the table doesn't drink. Same answer: separate expense, split among the people who drank. This is the single most common source of quiet resentment in a group.
- A service charge you didn't agree to. It's part of the total, so it scales like tax. If you get it removed, remove it before you split.
- Someone paid partly in cash. Record the full bill against whoever's card was charged, then record the cash as a settlement from the person who handed it over. Two clean rows beat one confusing one.
Do it before the card machine arrives
The whole thing is: total, four numbers, save. It takes less time than the card machine takes to boot, and the balances are settled before anyone stands up. That's the difference between a group that keeps using an app and a group that goes back to "I'll get you next time", a promise nobody has ever kept twice.