What the Unequal Bill Split Calculator does
This calculator splits a bill that was never equal. Assign each item to the people who actually had it, tick the ones that were shared, then add the service charge, tax, tip or discount - they are apportioned in proportion to what each person's items came to, rather than divided by the number of heads. The result is what each person owes to the penny, plus a short list of payments that settles everyone up.
It exists because dividing by the number of people is only fair when everyone ordered the same thing. One person having tap water and a starter while another has three courses and most of the wine is the normal case, and doing that arithmetic on a phone calculator while the waiter waits is where mistakes happen. Names and amounts stay in your browser: nothing is uploaded, nothing is saved, and closing the tab loses it.
How to use it
- List the people, one per line. These names are only used to label the columns and never leave the page.
- Add each line of the bill: what it was and what it cost. Tick everyone who shared it - a starter for the table stays ticked for everyone, someone's steak is ticked for them alone.
- Enter the service charge, tax and tip as percentages, and any discount as an amount. Choose whether the tip is worked out before or after tax and service, because the two give different answers.
- Read the table: items, service, tax, tip and discount per person, and the total each owes. The shares always add up to the bill exactly.
- Open the settle-up section and enter what each person has already paid - usually one person paid the whole bill. The list of payments that squares everyone appears underneath, ready to copy into a group chat.
Reading the results
The "Items" column is the person's own food and drink, with anything shared already divided among the people who shared it. Everything after it is their proportional share of the extras.
Proportional apportionment means someone whose items came to a quarter of the bill pays a quarter of the service charge. That is the same answer as charging the percentage to each person's share separately, which is why it is the convention.
Shares are rounded to the penny using largest-remainder allocation, so the individual amounts always sum to the bill. Without it, three people splitting 10.00 each pay 3.33 and the table is 1p short.
A balance is what someone has paid minus what they owe: positive means they are owed money back, negative means they still owe. The settle-up list turns those balances into actual payments.
Worked example: dinner for three with a service charge
A starter to share is 12.00, so it is 4.00 each. Ann's main is 18.50, Ben's is 22.00 and Cat's is 16.50. A bottle of wine at 27.00 is shared by Ann and Ben, so 13.50 each. Cat did not drink.
Item shares are therefore Ann 36.00, Ben 39.50 and Cat 20.50, which add to the 96.00 subtotal.
The restaurant adds 12.5% service, which is 12.00. Apportioned by item share that is 36/96 x 12 = 4.50 for Ann, 39.5/96 x 12 = 4.9375 for Ben and 20.5/96 x 12 = 2.5625 for Cat. Rounded to pennies by largest remainder, Ben's 0.9375 rounds up to 4.94 and Cat's 0.5625 down to 2.56, so the three still add to exactly 12.00.
Totals: Ann 40.50, Ben 44.44, Cat 23.06 - and 108.00 altogether. Ann paid the whole bill on her card, so Ben pays Ann 44.44 and Cat pays Ann 23.06, and everyone is square in two payments. An even three-way split would have charged Cat 36.00: nearly 13.00 too much for a person who had a starter and a main.
Formulas and scoring rules
- Share of an item
share = amount x weight / sum_of_weightsWeights are 1 each unless you set them, so a shared item is simply divided by the number of people sharing it.- Service charge
service = (subtotal - discount) x service_percent / 100- Tax
tax = (subtotal - discount + service_if_taxed) x tax_percent / 100Whether tax applies to the service charge varies by country; the checkbox decides.- Tip
tip = base x tip_percent / 100base is the food and drink before tax and service, or the full total including them - your choice.- Apportioning an extra
person_share = extra x person_items / total_itemsRounded to the penny by largest remainder so the parts sum to the extra exactly.- Balance
balance = paid - owedPositive means they are owed money. The settle-up pays the largest debt to the largest credit until everyone is zero.
Why proportional beats per-head for tax and service
A service charge is a percentage of the bill, so the natural way to share it is by the share of the bill each person created. Dividing it equally quietly transfers money from the cheap eater to the expensive one - the very thing an itemised split is meant to stop. The same is true of sales tax, which is charged on the price of what was sold, and of a percentage discount.
A flat charge is different. A cover charge, a corkage fee or a fixed booking fee is the same for every head regardless of what they ordered, so add it as an item ticked for everybody rather than as a percentage.
The settle-up, and why nobody claims it is optimal
Once each person's share and each person's payments are known, the remaining question is who hands money to whom. The calculator pairs the largest debtor with the largest creditor and repeats. That finishes in at most one payment per person, which for a normal group is the fewest payments possible.
Finding the genuinely minimal number of transfers for any set of balances is equivalent to a partition problem and is NP-hard, so no tool can promise it for every case without a search. This one is honest about that: it describes its answer as a short set of payments, not the shortest possible.
Limitations: what the result does not prove
- It divides money; it does not decide what is fair. Whether the person who ordered the expensive wine should pay for all of it is a conversation, not arithmetic.
- The tax model is a single percentage. Bills that apply different rates to food, alcohol and soft drinks need those lines entered as separate items with their tax included in the amount.
- Currency is cosmetic. Everything must be entered in the same currency; there are no exchange rates here, live or otherwise.
- Nothing is stored. Reload the page and the bill is gone - use the CSV or the copied summary if you need to keep it.
- Settling up assumes people will actually pay. It is a list of transfers, not a payment service, and it does not know or check anyone's bank details.
Privacy: where your data goes
Everything you paste, type or drop is processed in this browser tab. It is not uploaded, logged, stored or sent to analytics. Session recording and tag-manager scripts are switched off on this page.
Standards and sources
- UK Government guidance - tips, gratuities, service charges and troncs
- Employment (Allocation of Tips) Act 2023
- Largest remainder method (apportionment of indivisible units)
Frequently asked questions
How do you split a bill when everyone ordered something different?
Assign each item to the person who ordered it, tick the shared items for everyone who shared them, then apportion service, tax and tip in proportion to what each person's items cost. That is exactly what this calculator does, and it takes about a minute for a table of six.
Should the service charge be split equally or in proportion?
In proportion, because it is a percentage of the bill. Splitting a percentage charge equally means the person who spent least subsidises the person who spent most, which defeats the point of itemising. A flat cover charge is the exception - enter that as an item ticked for everybody.
Should the tip be calculated before or after tax?
Both conventions exist. Tipping on the pre-tax amount is common in the United States and is the more conservative choice; tipping on the total including tax and service is simpler and slightly more generous. The calculator offers both and shows the resulting figure, so you can decide with the number in front of you.
How do you handle the odd penny when a bill will not divide?
The shares are rounded to the penny and the leftover pennies are given to the largest remainders, so the individual amounts always add up to the bill exactly. Nobody is short-changed by more than a penny, and the total is never wrong.
What if one person paid the whole bill?
Put the full amount in that person's "paid" box in the settle-up section. Everyone else's balance becomes what they owe that person, and the payment list shows each transfer, ready to copy into a group chat or a payment app.
Can one person be counted as more than one share of a shared item?
Yes - the engine supports weights on a shared item, so a platter can be split two to one. In the page, the simplest way is to split the line in two: enter the item at the amounts each side really had, or add the item twice with the right proportions.
Does the tool store our names or what we spent?
No. It runs entirely in your browser with no network calls, saves nothing to your device, and forgets everything when you close the tab. The CSV and the copied summary are produced locally.
Why does my even split differ from this by so much?
Because an even split charges everyone the average. In the worked example above, the person who had no wine and the cheapest main would pay 36.00 instead of 23.06 - about 56% more than what they ordered cost. The gap is widest when drinks are unevenly shared.
Last reviewed by the A2Z.Tools team against the sources listed above.
