Split a bill by days

Calculator

Enter the amount of the bill, the period it covers (for example a billing year) and, for each person, the first and the last day they lived there. An empty date means the start or the end of the period. It works for 2 to 16 people and periods of up to 3,660 days, and calculates in euros. The pre-filled values are an example. What you enter stays in your browser and is neither stored nor sent anywhere.

How it is calculated

1. The amount is converted to whole cents, so there are no rounding errors.
2. For each person, the days they lived there within the period are counted. The first and the last day both count: 1 to 31 May is 31 days, and “from” and “to” on the same day is 1 day. Days outside the period do not count.
3. A person’s share is the amount times their days, divided by the total days of everyone in the list. Someone who lived there twice as long pays twice as much.
4. The calendar is right: a leap year has 366 days, 29 February counts only in a leap year and summer time does not shift a day.
5. Each share is rounded down to whole cents. The cents left over go one each to the people with the largest fractional parts (the largest remainder method); on a tie, to the person higher in the list. So the shares always add up to exactly the bill, and no share is a cent or more away from the exact value.

Move-in and move-out days

Both days at the edges count. If one person moves out on 31 May and the next moves in on 1 June, every day belongs to exactly one person. If the next person moves in on 31 May already, that day counts for both and the bill is spread over one more person-day. So enter as the last day the day the person still lives there, and as the first day the day they move in. If a handover day should count only once, give it to just one of the two people. Which days you count is for your flat to agree; the calculator only follows this rule.

Example: an electricity bill with a move-out and a move-in

The electricity bill for 2026 is €1,234.56. Anna lives there all year (365 days), Ben moves out on 31 May (151 days) and Cem moves in on 1 June (214 days). That makes 730 person-days, so one day costs about €1.691 per person. Rounding down leaves one cent over, which goes to Ben because their remainder is the largest. After that, the shares add up to exactly €1,234.56.

Which bills it suits

The calculator suits costs that affect everyone equally for as long as they live there: electricity, internet, streaming, the Rundfunkbeitrag (broadcasting fee) or a back payment from the utilities statement. What is usual in a flat share is covered in utilities in a flat share, which counts in months. For a sublet, see subletting a room; for moving out, the moving-out checklist; for moving in, the moving-in checklist. Rent by room size is split by the rent split calculator.

What the calculator does not do

It spreads the whole bill over the person-days you enter. Days on which nobody is entered are therefore not carried by one person alone; they are spread over everyone. It does not know consumption per person, unequal weights or currencies other than euros. It replaces neither the landlord’s statement nor legal advice.

Enter the result in ManaWG

ManaWG does not split costs by days. Create the expense in the shared expenses, choose “Manually” under “People involved and split” and enter each person’s amount from the calculator. ManaWG shows whether the shares add up to the expense. ManaWG does not move any money itself: you pay by bank transfer, in cash or however you like and mark the settlement as paid.

Open source

ManaWG is open source under Apache-2.0, and the source code is on GitHub.