Math Tools
Online Expense Splitter and Bill Sharing Calculator
Calculate what each person paid, owes, and should transfer by choosing the participants separately for every expense.
Item-specific equal shares
Split expenses and settle balances
All arithmetic uses integer satangs. Names and expenses remain on this device.
Quick answer
How can I split several expenses fairly?
Record who paid each expense and who participated. The tool divides each amount into integer satangs, totals every person's payments and responsibility, then nets the balances and creates transfers that settle the group.
How to use this tool
- Enter one member per line or separate names with commas, then update the group.
- Enter an item, baht amount, payer, and the participants for that expense, then add it.
- Review paid, owed, net, and transfer totals, then export to Print, Excel, PDF, or TXT if needed.
How the calculation works
Every amount is parsed as integer satangs because one baht has 100 satangs. For each expense, integer division assigns a base share to every participant, then any remainder is distributed one satang at a time in member order. Net balance equals amount paid for the group minus assigned responsibility. Debtors then transfer to creditors through a deterministic matching pass until every net balance is zero.
Examples
| Example | Input | Expected result |
|---|---|---|
| Dinner shared by four | |
Each person owes THB 300 and Alice has a THB 900 credit before other expenses |
| Taxi used by three | |
Each participant owes THB 120; Dan is not charged for this item |
| A share with a satang remainder | |
THB 33.34, 33.33, and 33.33 in member order, totaling exactly THB 100.00 |
Limitations
- Amounts are Thai baht from THB 0.01 to 99,999,999.99 per expense, with 2–20 members and at most 100 expenses.
- Each item is split equally among its selected participants. Weighted shares, percentages, tax, tips, and automatic exchange rates are not supported.
- The payer does not have to participate in the item, but must belong to the group; every expense needs at least one participant.
- Changing the member list clears current expenses so records cannot silently point to the wrong person.
- Transfers settle all net balances but do not guarantee the mathematical minimum number of transactions and are not evidence of debt or financial advice.
Frequently asked questions
How are leftover satangs assigned?
The tool divides integer satangs and assigns any remainder one satang at a time in member order. No money is created or lost, and the result is reproducible.
Can an expense include only some group members?
Yes. Each expense has its own participants. A member who is not selected owes nothing for that item.
Does the transfer list guarantee the fewest transactions?
No. It uses deterministic debtor-creditor matching so the result is easy to audit and fully settles net balances, but it does not solve a minimum-transaction optimization problem.
Does the website store names or expenses?
No. Calculation, copying, and file generation happen in your browser without sending group data to the server.
References
- Thailand Currency Act — one baht is divided into 100 satangs (Bank of Thailand) Verified 2026-07-31
- Legacy THcount — expense sharing calculator Verified 2026-07-31
Content and calculation method last reviewed: