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Shared Expenses Calculator

Settle up shared costs for a trip, a house or a group: enter what each person paid and get the fewest simple payments that make everyone even.

Level: Grades 6–7

  • Common Core standard 7.NS.A.3Solve real-world and mathematical problems involving the four operations with rational numbers.
  • Common Core standard 6.RP.A.3Use ratio and rate reasoning to solve real-world and mathematical problems, e.g., by reasoning about tables of equivalent ratios, tape diagrams, double number line diagrams, or equations.
Printable worksheet

Shared Expenses Calculator

Inputs

One amount per person, in order: Person 1, Person 2, and so on. Enter 0 for anyone who paid nothing.

Leave blank to split equally. Otherwise one weight per person, for example 2, 1, 1, 1 if Person 1 covers two people.

Result

Who pays whom

Person 3 pays Person 1 $70.00; Person 4 pays Person 1 $30.00; Person 2 pays Person 1 $10.00

Person 3 pays Person 1 $70.00; Person 4 pays Person 1 $30.00; Person 2 pays Person 1 $10.00. That settles $280.00 in 3 payments.

Total spent
$280.00
Fair share per person
$70.00Individual shares are rounded to the cent so they add up to the total.
Payments needed
3

See the step-by-step solution ↓

Balance for each person
Balance for each person
PersonPaidFair shareBalance (+ is owed)
Person 1$180.00$70.00$110.00
Person 2$60.00$70.00-$10.00
Person 3$0.00$70.00-$70.00
Person 4$40.00$70.00-$30.00

Step-by-step solution

  1. Total spent: add up what everyone paid

    $180.00+$60.00+$0.00+$40.00=$280.00

  2. Divide the total equally among 4 people, to the cent, to get each fair share

    $280.004=$70.00

  3. Person 1: what they paid minus their fair share shows where they stand (is owed money)

    $180.00−$70.00=$110.00

  4. Person 2: what they paid minus their fair share shows where they stand (owes money)

    $60.00−$70.00=−$10.00

  5. Person 3: what they paid minus their fair share shows where they stand (owes money)

    $0.00−$70.00=−$70.00

  6. Person 4: what they paid minus their fair share shows where they stand (owes money)

    $40.00−$70.00=−$30.00

  7. Settle up: the person who owes most pays the person owed most, until everyone is even

    Person 3 pays Person 1 $70.00; Person 4 pays Person 1 $30.00; Person 2 pays Person 1 $10.00

Test yourself

20 quick questions built from this calculator's formula: work out results, predict what happens when an input changes, and work backward from an answer. Every answer comes with the working.

Please note: Results are estimates for planning and comparison. Lenders, banks, and tax authorities may round differently or include fees not modeled here, so confirm figures with your provider before deciding.

What this calculator does

Find out who owes whom, and how much, after a trip or a month of shared bills. Usually one person paid for the cabin, another for groceries and someone else for nothing at all. This calculator takes what each person paid and works out everyone's fair share. Then it turns the differences into a short list of payments, so everyone ends up even.

Shares can be equal or weighted. If one person is paying for a partner or a child, give them a share of 2. If someone joined for only part of a trip, give them a smaller share. Amounts are worked in whole cents. The shares are rounded so they add up to the exact total, so the payments balance to the penny.

Where it's used

Why this math matters outside the classroom:

  • Group trips. Four friends who spent $280 find each owes $70, so the one who paid $180 should get $110 back.
  • Shared households. Housemates total a month of groceries and utilities, then settle with one or two transfers instead of many.
  • Families on holiday. Two families of 3 and 2 split a $1,500 rental by shares 3:2, so their fair shares are $900 and $600.
  • Signed numbers. Students treat money owed as negative and money due as positive, and check that the balances add to zero.
  • Club budgets. A club treasurer settles what members spent on supplies for an event against an equal share per member.

Grade level and standards: Grades 6–7; Common Core State Standards for Mathematics 7.NS.A.3, 6.RP.A.3. © Copyright 2010. National Governors Association Center for Best Practices and Council of Chief State School Officers. All rights reserved.

How to use it

  1. List what each person paid, in order, separated by commas. Enter 0 for anyone who paid nothing.
  2. Leave the shares blank to split equally. Or enter one weight per person, in the same order.
  3. Read the list of payments that settles the group. Check each person's balance in the table.

What the inputs mean

Amount each person paid ($)
Add up everything each person paid for the group before you enter it. Person 1 is the first amount, Person 2 the second, and so on.
Shares (optional)
Weights, not dollar amounts. 2, 1, 1 means the first person's fair share is twice each of the others'. A 0 share means that person owes nothing toward the costs.

Formula and method

total = sum of everything paid
fair share = total × (your share ÷ sum of shares), rounded to the cent so shares add up to the total
balance = amount paid − fair share
settle: the person who owes most pays the person owed most, repeat until all balances are zero

Your balance is what you paid minus your fair share. A positive balance means you paid more than your share and are owed money. A negative balance means you owe. The balances always add up to zero, because the fair shares add up to exactly what was spent.

To settle, the calculator pairs the person who owes the most with the person owed the most. It pays off the smaller of the two amounts, then repeats. Each payment clears at least one person. So a group of n people (n is the number of people) needs at most n − 1 payments.

Sometimes a total doesn't split evenly. Then the leftover cents go to the people whose exact shares were closest to the next cent. That way nobody is off by more than a cent.

Worked example

Four friends share a weekend. Person 1 paid $180 for the rental, Person 2 paid $60 for food, Person 3 paid nothing and Person 4 paid $40 for gas. They split equally.

  1. Total spent: $180 + $60 + $0 + $40 = $280.
  2. Fair share: $280 ÷ 4 = $70 each.
  3. Balances: Person 1 is owed $110; Person 2 owes $10; Person 3 owes $70; Person 4 owes $30.
  4. Settle: Person 3 pays Person 1 $70.00, then Person 4 pays Person 1 $30.00, then Person 2 pays Person 1 $10.00.

Result: Person 3 pays Person 1 $70.00; Person 4 pays Person 1 $30.00; Person 2 pays Person 1 $10.00. Three payments settle the $280.

Understanding the result

Each line of the result is one payment to make. Once they're all made, everyone has paid exactly their fair share.

The table shows where each person stands before settling: what they paid, what their share was, and the difference.

If the group keeps sharing costs, you don't have to settle every time. Carry the balances forward, and run the calculator again with the running totals.

Assumptions and limitations

  • Every cost is shared by the whole group in the same proportions. For costs only some people share, run those separately and combine the balances.
  • Amounts are in one currency and are worked in whole cents.
  • The settling method (always pairing the biggest amounts first) is short and simple. But in some groups, a cleverer pairing can save one payment.
  • People are numbered, not named. Keep a note of the order you entered them in.
  • Shared costs that only some of the group used, and items one person should pay for alone, aren't split automatically.

Frequently asked questions

How do I split when someone came for only part of the trip?

Use shares. If a trip lasted four nights and one person came for two, give everyone else a share of 4 and that person a share of 2. Their fair share will be half of a full share.

Why are the shares sometimes a cent different?

Money can't be split below a cent. When $100 is split three ways, the shares are $33.34, $33.33 and $33.33, so they still add up to $100. The extra cent goes to the person whose exact share was closest to rounding up.

Is this the fewest possible payments?

A group of n people never needs more than n − 1 payments here, and the result is usually the fewest possible. Now and then, a few people's balances happen to cancel out among themselves. Then a different pairing can save a payment.

Can someone who paid more than everyone else still owe money?

Yes, with weighted shares. If one person's share covers three people, their fair share may be bigger than what they paid, even if they paid the most.

How this calculator is checked

Method: Proportional cost sharing with largest-remainder cent allocation; greedy debt settlement matching the largest debtor with the largest creditor. The calculation is covered by automated tests with known reference values and edge cases. Last updated 2026-10-18. Found a problem? Tell us.

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