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An assumption-led UK calculator

Rent or buy, on equal terms.

Same starting cash, same monthly budget. Change every assumption when you are ready.

7 quick inputs15 refinementsMethodology

Your decision ledger

Start with the numbers you know.

New scenario

Start with a clean calculation?

Save the current scenario first if you want to load it again later.

Save scenario

Give this scenario a name.

It will stay in this browser and will not be included in shared links.

Saved in this browser

Load a saved scenario.

Choose a scenario to replace the values currently in the calculator.

Saved scenarios

No saved scenarios yet.

Set up a calculation, then choose Save above the calculator.

Clearing site data removes your working draft and saved scenarios. Shared URLs remain separate.

Public link

Copy a share link?

The URL includes the property price, rent, deposit and other assumptions. Anyone with the link can read them. Saved scenario names are not included.

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Quick comparison

Seven inputs shape the first answer.

Saving draft

Example values
01

Home and rent

The home and rental you are actually comparing.

SDLT treatment — England and Northern Ireland
02

Mortgage

A repayment mortgage; eligibility and remortgaging are not assessed.

First mortgage payment£1,938

Current result

Buying is ahead by £126,755

After 10 years under your selected assumptions. Values are shown in nominal pounds.

Explore the full analysis

Buying finishes ahead in all three tested cases.

Buying margin across the cases: £24,099–£238,980.

Durable crossover

Buying stays ahead from about year 2.2

Refine the model

Make the defaults yours.

These values already affect the answer. Open a section to change them.

15 refinements
Growth and returnsProperty 2.5% · manualRent 3% · manualInvesting 5% · manual

UK property evidence

Attach UK HPI history by area and property type.

Historical evidence

Ground the growth assumption.

Choose an area, property type and history. We apply the nominal annual change and show CPIH-adjusted history as context, never as a prediction.

UK rent evidence

Attach ONS rent history by area and rental segment.

Historical rent evidence

Ground the rent assumption.

Choose an area, rental segment and history. The nominal index change enters the model; matched CPIH remains context.

Investment evidence

Attach filed fund history converted to GBP with matched CPIH.

Calculated historical assumption

Ground the return in fund history.

Choose a representative fund and period. We calculate its unhedged GBP annual return and pair it with realised CPIH over the same calendar years. The nominal result is the rate applied to the calculator.

Display assumption

Future inflation

Converts projected values to today’s money; it does not change the nominal cash flows.

Historical rates are evidence, not forecasts. Editing an applied rate detaches its evidence; manual rates are nominal.

Detailed costsBuying £3,500 fixed + 0%Upkeep 1% + £35/monthSelling 1.5%Renter £15/month + £300 upfront + 1-month deposit

Your analysis

See both paths on equal terms.

The result updates as you edit the setup above. It is an illustration under your assumptions, not a prediction.

Selected assumptions
Value display

Buying is ahead

£126,755

after 10 years, if every assumption happens exactly as entered. Values are shown in nominal pounds.

Durable crossover

Buying stays ahead from about year 2.2

Buying wealthRenting wealthNominal estimated liquidation value
Year-by-year net wealth for buying and renting in nominal poundsThe solid line shows buying and the dashed line shows renting. At the end of the selected period, buying wealth is £272,486 and renting wealth is £145,731, shown in nominal pounds.-£21.8k£57.2k£136.2k£215.3k£294.3kNow3y5y8y10y

Buying finishes ahead in all three tested cases.

Three stress cases show how much the margin can move. They are not probabilities.

Rent-favouring case

Outcome: buying ahead

£24,099

Your assumptions

Outcome: buying ahead

£126,755

Buy-favouring case

Outcome: buying ahead

£238,980

Buying wealth

£272,486

£269,696 equity before selling costs

Renting wealth

£145,731

£143,631 invested + refundable deposit

Month one · nominal cash flow

Buying vs renting + investing.

Buying path

Buying: £2,349 housing outgoings plus £0 invested in the market equals a total monthly commitment of £2,349.

Renting path

Renting: £2,115 housing outgoings plus £234 invested in the market equals a total monthly commitment of £2,349.

Investment is automatic. Whatever remains after housing costs is invested in the market, keeping both paths on the same monthly budget.

Recalculated every month

Cash needed to buy
£83,500
Renter starts invested
£81,100

Illustrative only. The model keeps its cash flows nominal. Any historical evidence enters as a nominal annual rate. It assumes a constant mortgage rate, full rental-deposit return and no investment tax or fees. The today’s-money option uses your 2% future inflation assumption as a display conversion and does not change the nominal winner. It does not assess affordability or mortgage eligibility.

Sensitivity range

How the result changes.

Explicit stress cases, not probabilities. Each card shows the rates used; amounts are in nominal pounds.

Rent-favouring case

Property growth 1.5 points lower, rent growth 1 point lower and investment return 1 point higher.

Outcome

Buying ahead

£24,099

Property
1%
Rent
2%
Investing
6%

Your assumptions

Your selected assumptions, without an implied probability.

Outcome

Buying ahead

£126,755

Property
2.5%
Rent
3%
Investing
5%

Buy-favouring case

Property growth 1.5 points higher, rent growth 1 point higher and investment return 1 point lower.

Outcome

Buying ahead

£238,980

Property
4%
Rent
4%
Investing
4%

Unrecoverable cost totals are shown in nominal pounds.

Unrecoverable buying costs

£236,347
SDLT and buying costs
£16,000
Mortgage interest
£156,411
Maintenance and insurance
£55,295
Service charge and ground rent
£0
Estimated selling costs
£8,641

Unrecoverable renting costs

£290,990
Rent paid
£288,890
Renter insurance
£1,800
Other monthly costs
£0
One-off renter costs
£300

How the comparison stays fair

How the comparison is structured.

01

Fair by construction

Both paths start with the same cash and use the same monthly budget.

02

Scenario range

Conservative, base and optimistic cases stay visibly distinct.

03

Private by default

Your scenario stays in this browser unless you choose to share a link.

What this cannot know

Uncertainty remains part of the answer.

House prices, rents, mortgage rates and investment returns can all move differently from the past. That is why this calculator shows a range and makes every assumption editable.

The financial result is only one part of the decision. Stability, flexibility, schools, commute, repair appetite and the chance you move sooner still belong in the conversation.