Rented normally, it costs you £475 a month. That is £5,705 a year, every year you hold it.

Will it pay?Calculator

You top up £475 a month — the mortgage takes 87p of every pound of rent

Borrowing £87,765 less would close that shortfall — which is £87,765 more cash at the start, on top of the deposit.

£2,519 mortgage

£2,882 rent in£475 short

◧ market rent £2,882 · 30 comps2 empty weeks a year assumed

What if I change my assumptions?The dials

At the asking price, 25% deposit, 6.50% charged

Change any of these 16 and every card on this page changes with it. The 6.50% is the 5.75% quoted plus a company premium.

◧ worked out from local rents

What will it cost me to buy?Breakdown

£220,650 + refurb costs

And about £28,524 more over five years, because it loses £475 every month you hold it — before any repair. That already assumes the rent never falls.

£220,650 to buy it

deposit · stamp duty · solicitor · fees~£19,990, unseen

□ works not inspected

What would have to be true?The working

£115,000 off and it stops losing money

At the asking price you feed it £475 a month. At £502,963 the rent covers everything — leaving stamp duty of £40,296 at that price.

offer £502,963

asked £620,000

◧ worked back from the rent■ stamp duty re-bandedrounded down to £5,000 — the rent it works back from is an estimate

What will the rent borrow?Lender test

The rent carries £305,782 of the £465,000 loan

That £159,218 is yours to find on top of the deposit. Tested at 125% instead of 145% — a company or a basic-rate taxpayer usually is — the gap is £110,292. Lenders test the rent at 7.5% and need it to cover 145% of the payment.

£4,214 needed

more than the £2,771 rent

stressed at 7.5%, 145% cover

◧ rent after empty weeks £2,771PRA-style test

How big is it, really?The plan

One figure, and nothing checking it 868 sq ft

Only the agent’s figure exists for this house. Open for what that means.

□ area unchecked — agent’s own

Is it a good location?Open the map

London, SE10 0JY

Flood risk checking… — open for the map, the schools and the rest.

Article 4Not assessed for this address

■ postcode area, not this address

What could kill thisThe checks

You would need a licence from the council first

Letting without the council’s licence is an offence, and the fee is in no figure here.

2 problems found · 2 came back clear · 5 we could not check

■ from council licensing registerlisting last seen 15 Sep 2026

Which strategy wins?The ways to run it

Every way loses money — Standard rental loses least, at £475 a month

Let it to the council: £5,688 a year less, but they keep paying when it is empty.

Standard rental−£475 · £240,640 in

Guaranteed council rent−£949 · £240,640 in

Rent by the room−£1,056 · £240,640 in

Housing-benefit rent−£1,347 · £240,640 in

Each row: money kept a month, then the cash it ties up. Not compared: Do it up, then remortgage (pays back at the remortgage) · Short-stay let (no local short-let data) · Buy, improve & sell (pays out on sale)

◧ 4 ways, one measureranked on money kept each month, at the asking price

What would you walk away with?The five-year sums

−£55,135 after five years on the cash you put in, before tax on the sale

Less than the same cash would have made in a savings account, after tax on the interest. The savings account’s capital is not at risk; the property’s is. A fall of about 25% in the price would leave nothing from a sale after selling costs, and you would still owe the lender any shortfall. That is the £240,640 you put in. The 5-year fix runs past this 5-year hold, so the rate reset comes after it.

◧ 2.0%/yr growth assumed