Valuation & costs
Selling a House and Buying a New One: The Numbers
To work out what you can afford on your next home when moving, start with your net sale proceeds (sale price minus mortgage and selling costs), add any extra deposit and your new mortgage borrowing, then subtract the buying costs of the new home — Stamp Duty, conveyancing, survey, mortgage and removal fees. The result is your realistic budget. Selling first gives you firm figures and a stronger buying position.
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- Proceeds+ deposit + borrowing
- Stamp Dutyand buying costs
- Sell firstfirm figures
Start with your net sale proceeds
The foundation is what you will actually walk away with from your current sale: the sale price minus your mortgage redemption and selling costs (agent, legal, removals, any early-repayment charge) — see how much will I make?. This net figure becomes the deposit (or part of it) for your next home, so getting it right is the starting point for working out what you can buy.
Add your borrowing and deposit
To your net proceeds, add any extra savings you’ll put toward the deposit, and your new mortgage borrowing (what a lender will lend you, based on income and affordability). The total — proceeds + extra deposit + borrowing — is the maximum purchase price before costs. A mortgage broker can confirm your borrowing capacity; if you are porting your existing mortgage, factor that in (see porting).
Subtract the buying costs
| Buying cost | Detail |
|---|---|
| Stamp Duty (SDLT/LTT/LBTT) | Depends on price; check GOV.UK |
| Conveyancing | £850-£1,800 + disbursements |
| Survey | £400-£1,500 |
| Mortgage fees | Arrangement & valuation |
| Removals | £400-£1,500+ |
These reduce what you can spend on the property itself, so budget for them.
A worked example
If your net sale proceeds are £143,000, you add £10,000 savings and a £180,000 mortgage, your gross budget is £333,000. Subtract, say, £6,000 Stamp Duty, £1,500 conveyancing, £600 survey, mortgage fees and £1,000 removals (~£9,500 total), and your realistic purchase price is around £323,000. Adjust for your own figures and check current Stamp Duty rates.
Why selling first helps the numbers
Working all this out is far easier — and your figures firmer — if you sell first, because you know your exact net proceeds and become a chain-free, proceedable buyer (stronger in negotiations). Buying first risks bridging costs and the Stamp Duty surcharge on owning two homes (see buy before selling?). A fast cash sale lets you sell first without a long wait, then buy from a position of strength.
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Written & reviewed by Lisa Hayes, Founder
Lisa Hayes is the founder of Ready Steady Sell and an independent UK home-selling expert with over a decade helping homeowners weigh cash house buyers, property investors and the wider fast house-sale industry — without pressure or hidden fees. Every guide is reviewed for accuracy under our editorial standards.
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Frequently asked questions
Straight answers, no sales talk
How do I work out what I can afford when moving house?
Take your net sale proceeds (sale price minus mortgage and selling costs), add extra deposit and new mortgage borrowing, then subtract the buying costs (Stamp Duty, conveyancing, survey, mortgage, removals).
What costs are involved in buying my next home?
Stamp Duty, conveyancing (£850-£1,800 plus disbursements), a survey (£400-£1,500), mortgage fees, and removals. Check current Stamp Duty rates on GOV.UK.
Should I sell or buy first when moving?
Selling first gives firm figures and a stronger, chain-free buying position. Buying first risks bridging costs and the Stamp Duty surcharge on two homes.
How do I know my new mortgage borrowing?
A mortgage broker or lender confirms your borrowing capacity based on income and affordability. If porting your existing mortgage, factor that in.
Does Stamp Duty affect my moving budget?
Yes — Stamp Duty (or LTT in Wales, LBTT in Scotland) on your new home reduces what you can spend on the property. Budget for it from your figures.
How can a fast sale help me buy?
A cash sale lets you sell first without a long wait, giving firm net proceeds and making you a chain-free, proceedable buyer in a strong negotiating position.