The Fairness Engine
We're the referee, not the cop. Here's the "why" behind the "how."
Proportional splits
When everyone doesn't stay the full month, we weight each person's share by their active days—so nobody subsidizes someone else's travel.
House Wall photos
Wall photos (receipts, pics, screenshots) are deleted after 2 days. Text notes and polls stay until someone removes them.
Guest fees & house rules
Long-term guests? One-off costs? Your house can decide what counts and who pays—so the rules stay transparent.
Stock buy-backs
When someone moves out—or the group buys shared supplies—we keep transfers explicit so nobody's left holding the bag.
Example: one roommate buys a shared router. Later, when someone leaves, HabiMate can record a clean "buy-back" so ownership (and the money) stays fair.
How we split cents
We only use whole cents. If the total doesn’t divide evenly, everyone gets the base amount and leftover cent(s) go to the first people in your participant list—one cent each.
Example: €10.00 split 3 ways
- €10.00 = 1,000 cents
- 1,000 ÷ 3 → €3.33 each, with 1 cent left over
- Shares: €3.34 · €3.33 · €3.33 (adds up to exactly €10.00)
The extra cent goes to the first person in the list order used for that split (Split with on a bill, or Who reimburses on a buy-back). Any further leftover cents go to the second person, then the third, and so on—same rule every time.
Equal split: each person gets floor(total ÷ people). Remainder cents (0 to people−1) are distributed one at a time from the start of that list.
Same rule in the fairness engine and in the HabiMate app when you add expenses.
Bills, buy-backs & balances
Bill splits and stock buy-backs both use the cent rule above. Buy-backs are separate transfers from everyday expenses so reimbursements stay clear on Pay.
Important. HabiMate helps your household track and agree on numbers. It does not decide legal disputes, enforce payments, or replace professional advice. For tax, tenancy, deposits, or court matters, keep your own records and consult a qualified professional. See also our Privacy & Trust page for how we describe limitations on liability in plain language.
Live calculator · add your house
Fairness Simulator
Add roommates, set days home or buy-back roles, then generate a settlement preview—the same ideas HabiMate uses in the app.
Example: €10.00 split 3 ways: €3.34 · €3.33 · €3.33. The extra cent goes to the first person in the list order used for that split (Split with on a bill, or Who reimburses on a buy-back). Any further leftover cents go to the second person, then the third, and so on—same rule every time.
Fair shares use each person's days in the house (weighted split, cent-safe). Settlement lines show who should pay the person who advanced the money.
Add your housemates, adjust amounts, then tap Generate settlement to see fair shares and transfers.