Free tool — no sign-up

Should I buy or keep renting?

Put your real numbers in. Get an honest answer — deposit timeline, monthly mortgage vs rent, 5-year cost comparison, and whether your income can support the purchase.

Based on real London property prices No AI tokens wasted on simple maths Takes 60 seconds

How this works — the thinking flow

1
Your rent situationWhat you pay now — your baseline cost of housing.
2
Your savings powerYour income and how much you can set aside each month toward a deposit.
3
Your target propertyWhat you want to buy and how much deposit you're aiming for.
4
Your mortgageThe rate and term you'd borrow on — we run the maths for you.
🏠
1 — Your Rent
What you pay today
£/mo
Your current monthly rent payment
yrs
Used to calculate rent already paid
💰
2 — Your Savings
Income & what you can set aside
£/yr
Used to check mortgage affordability (income × 4.5)
£/mo
How much you can put aside each month
£
What you've saved so far toward a deposit
% p.a.
Leave at 4.5% for a typical cash ISA
🏡
3 — Your Target Property
What you want to buy
£
Use OpenProp to find the lower quartile price in your borough — that's your realistic entry price
%
5% is the minimum for most lenders. 10–15% gets you better rates.
🏦
4 — Your Mortgage
Borrowing assumptions
% p.a.
Current 2-year fixed rates are typically 4–5%. Check MoneySupermarket for live rates.
yrs
Longer term = lower monthly payment but more interest paid overall
All calculations run locally in your browser. Nothing is sent to a server.
1
The cost of renting — what you've spent and what's ahead
This money is gone. It built no equity, no asset.
Rent already paid monthly rent × 12 × years renting —
Annual rent cost monthly rent × 12 —
Projected rent over next 5 years monthly rent × 60 months —
2
The deposit challenge — how long until you can buy
With compound interest on your savings, and what renting costs while you wait
Deposit required property price × deposit % —
Already saved your input —
Still to save deposit required − savings already accumulated —
Time to reach deposit n = log((D + S÷r) ÷ (A + S÷r)) ÷ log(1+r) — D=deposit, S=monthly savings, A=existing savings, r=annual rate÷12 —
Rent paid while saving monthly rent × months to save —
3
The mortgage — what you'd pay each month once you buy
Based on your rate, term, and loan amount
Loan amount property price − deposit —
Monthly mortgage payment PMT = L × r × (1+r)ⁿ ÷ ((1+r)ⁿ − 1) — L=loan, r=annual rate÷12, n=term in months —
Total interest paid over full term (monthly payment × term months) − loan amount —
4
Renting vs buying — the monthly comparison
Once you've bought, is the mortgage cheaper than what you pay in rent today?
Renting now
—
per month, builds no equity
Buying (mortgage)
—
per month, builds equity
Monthly difference monthly rent − monthly mortgage (positive = buying is cheaper) —
5
Affordability check — can your income support the loan?
Lenders typically cap mortgages at 4–4.5× your annual income
Annual household income your input —
Max mortgage (income × 4.5) income × 4.5 — lender rule of thumb; actual criteria vary —
Loan you need property price − deposit —
Surplus / shortfall max mortgage − loan needed (positive = surplus) —
Max property you could buy today max mortgage + deposit —
6
The 5-year view — renting vs owning over time
Total money out of your pocket over 5 years, and what you'd own at the end
5 yrs renting
—
monthly rent × 60 — nothing owned
5 yrs mortgage
—
monthly payment × 60 (interest + principal)
Equity after 5 yrs
—
deposit + principal repaid (iterative amortisation)
Interest paid over 5 years (monthly payment × 60) − principal repaid over 60 months —
Net cost: buying vs renting over 5 years 5yr mortgage interest − 5yr rent paid (negative = buying interest cheaper than rent) —
Formulas used in this calculator Deposit timeline: n = log((D + S÷r) ÷ (A + S÷r)) ÷ log(1+r) — D = deposit needed, S = monthly savings, A = existing savings, r = annual rate ÷ 12. Both the lump sum and monthly contributions are compounded.
Monthly mortgage payment: PMT = L × r × (1+r)ⁿ ÷ ((1+r)ⁿ − 1) — L = loan, r = annual rate ÷ 12, n = term in months. Standard repayment annuity formula.
Total interest (full term): (monthly payment × term months) − loan amount.
Equity after 5 years: deposit + principal repaid, calculated via iterative month-by-month amortisation over 60 months. Each month: interest = balance × r; principal repaid = payment − interest; balance reduced accordingly.
5-year interest cost: (monthly payment × 60) − principal repaid in 60 months.
Affordability (max mortgage): income × 4.5 — rule of thumb only; actual lender criteria vary by provider, income type, and outgoings.
⚠️ This calculator is illustrative only. It uses simplified assumptions: a fixed mortgage rate for the full term, no stamp duty, legal fees, survey costs, or ongoing maintenance included, and an income × 4.5 affordability rule of thumb (actual lender criteria vary). It does not constitute financial, mortgage, or property investment advice. Always speak to a qualified mortgage broker before making any purchase decision.