How it works
The calculator uses standard mortgage math and simple split rules. It’s for rough planning, not advice.
Mortgage payment
Fixed-rate amortization estimate.
Loan amount
Loan = house price − deposit (floored at 0).
Monthly payment formula
Payment = P · r · (1 + r)^n / ((1 + r)^n − 1)
Where P is principal, r is monthly interest rate (APR/12), and n is number of monthly payments (years·12).
Note: This estimate ignores taxes/insurance unless you include them in shared monthly costs.
Total housing cost
What you’re sharing each month.
Total housing cost = mortgage + council tax + utilities + insurance + maintenance buffer.
Shared monthly costs are anything you treat as joint: utilities, insurance, HOA, subscriptions, etc.
Groceries can be included as shared costs (or treated separately).
Leftover
What each person keeps after paying.
Leftover (A) = take-home (A) − A’s share.
Leftover (B) = take-home (B) − B’s share.
Related guides
Mortgage & bills split calculator
Run your numbers live and share a scenario link.
How to split bills when living together
A clear 3-step system that avoids monthly negotiation.
What counts as shared costs?
A clear shared-cost list and what to keep personal.
Should groceries be shared 50/50?
50/50 vs proportional vs hybrid grocery splitting.
How to budget maintenance costs
Why a buffer matters and how it changes monthly affordability.
Partner moves in later — how to split costs?
A calm way to define shared costs and contributions.
Buy in one name or joint names?
Neutral budgeting questions and how to agree contributions.
50/50 vs proportional vs custom splits
Choose a split that feels fair and stays sustainable.
Stress test for rate rises and one income
+1% / +2% and one-income checks in plain English.
Common questions (FAQ)
Quick answers, assumptions, and what this tool is (and isn’t).
Tip: open a guide in one tab and the calculator in another to compare options quickly.