How do we split a utility bill between roommates fairly?
Enter the bill and how many days each person was there. Set days to 0 for empty rows.
How this is calculated
Formula: Share = bill × (person's days ÷ total person-days). The even split is bill ÷ number of people.
Assumptions: Everyone uses about the same amount per day. Shares are rounded to the cent, so the total can be off by a penny.
Frequently asked questions
What is a person-day?
One person living there for one day. Three people for 30 days is 90 person-days.
Is splitting by days fair?
It is the most common fair method when someone moves in or out mid-month or is away for a long time.
Should fixed fees be split evenly?
Some households split fixed charges (like internet or service fees) evenly and only usage by days. Run the calculator twice if you prefer that.
Does this work for rent?
It can, but rent is often split by room size instead.