Buying Your Partner Out of the House: The Maths, the Steps, the Traps
One of you stays, one of you goes, and a number has to be agreed. How the buyout figure is actually calculated, the transfer-of-equity process step by step, the stamp duty rule that surprises everyone — and what to check if you’re the one being bought out.
Keeping the house and buying them out?
The whole plan stands or falls on one question: can you carry the new mortgage alone? Get that answered first — a whole-of-market broker runs it in one conversation, free.
Compare mortgage deals →★★★★★ Free · Independent · No obligation
Quick answer
Buying a partner out means paying for their share of the equity and taking sole ownership via a transfer of equity. The maths: property value − mortgage balance = equity; multiply by their percentage (50% unless a deed of trust says otherwise) and that’s the headline buyout figure — on a £300,000 home with £140,000 owing, a half share costs £80,000. Most people fund it by remortgaging: a new sole-name loan large enough to clear the old mortgage and pay the departing partner, which means passing affordability on one income — the gate the whole plan runs through. The process itself is quick and cheap by property standards (~£300–£800 legal costs, typically 4–8 weeks), but two traps catch people: stamp duty can apply — HMRC counts both cash paid and mortgage debt taken over as “chargeable consideration” (though transfers under a divorce court order are exempt) — and the departing partner isn’t free until the lender releases them, not when the deeds change. Both sides of the deal covered below. Position as of July 2026.
Your home may be repossessed if you do not keep up repayments on your mortgage.
In this guide
How much does it cost to buy your partner out?
Three numbers and one multiplication:
The buyout calculator, worked
Step 1 — value the property honestly. Get two or three estate-agent valuations (free) or a RICS valuation (a few hundred pounds, harder to argue with) and agree the figure — say £300,000.
Step 2 — subtract the mortgage. £300,000 − £140,000 owing = £160,000 equity.
Step 3 — apply their share. At 50%: £80,000 buyout. If a deed of trust records unequal shares — say 70/30 from unequal deposits — the split follows the deed: their 30% would be £48,000.
Step 4 — negotiate the adjustments. Real buyouts often move off the headline number: who paid the deposit, who’s covered the mortgage since separation, selling costs saved by not selling (~2–3% of value that a sale would have eaten), timing. The formula sets the anchor; the agreement sets the price.
The figure that matters just as much: the new mortgage you’ll carry. Clearing £140,000 and raising £80,000 means a £220,000 sole-name loan — and whether one income supports that is the question to answer before any negotiation gets emotional. A soft-searched decision in principle settles it in days.
The transfer of equity: step by step
- Agree the buyout figure (maths above) — in writing, even informally at first.
- Confirm you can fund it — affordability check or DIP on the full new loan.
- Apply for the remortgage or further advance (next section) with the buyout declared as the purpose.
- Instruct a conveyancer — they prepare the transfer deed (TR1), obtain the lender’s consent (the lender must approve the sole-name arrangement — they are not obliged to, even if you both agree), and handle any deed-of-trust unwinding. Cost: typically £300–£800 plus a small Land Registry fee.
- Completion day — the new mortgage draws down, the old one is repaid, the departing partner receives their money through the solicitor, and they’re released from the mortgage.
- Registration — the Land Registry records sole ownership. Done: typically 4–8 weeks end to end when the mortgage side runs smoothly.
Funding the buyout
Four routes, in order of frequency. Remortgage to release the money — the standard play: a new sole-name mortgage sized to old-balance-plus-buyout, mechanically identical to any equity-release remortgage, gated by solo affordability (maintenance income can count, term extension can help — the full solo-affordability toolkit is in our divorce mortgage guide, which is this page’s companion for the wider situation). A further advance from your current lender — sometimes simpler mid-fix, avoiding early-repayment charges. Savings or family money — cleanest of all; no affordability gate on the buyout itself, though the lender must still approve taking the mortgage solo. Family support structures — where solo affordability falls just short, guarantor and joint-borrower arrangements bridge the gap without giving the helper ownership. And if the gate won’t open at all: the honest alternatives are a deferred buyout (their share secured as a charge, paid on a future sale or remortgage) or selling — better named early than discovered at week six.
The buyout stands on one affordability answer
New loan, one income, maintenance counted properly, right lender — get the yes-or-no (and the how) before the negotiation, free.
Compare mortgage deals →★★★★★ Free · Independent · No obligation
Stamp duty on buying a partner out — the rule that surprises everyone
People assume no sale means no stamp duty. HMRC disagrees: SDLT is charged on “chargeable consideration” — the cash you pay for the share plus the portion of the existing mortgage debt you take over. Buy a 50% share by paying £80,000 cash and assuming their £70,000 half of the mortgage, and your consideration is £150,000 — above the £125,000 nil band, so a modest bill applies (2% on the excess: £500 in that example). The fine print that matters:
- Divorce and dissolution transfers are exempt — completed under a court order or formal separation agreement, the transfer is SDLT-free regardless of the sums. One more reason the consent order earns its keep.
- Unmarried couples get no exemption — the consideration rules apply in full, whatever the relationship’s length.
- A return may be due even at £0 tax — consideration of £40,000+ generally requires an SDLT return within 14 days of completion, even when nothing’s payable.
- Own another property? The additional-property surcharge can apply to the whole consideration — the classic ambush for a buyer who kept a flat from before the relationship.
Your conveyancer calculates this as standard — the point of knowing it now is budgeting, and structuring (married couples mid-separation: the court-order route isn’t just legal tidiness, it’s a tax exemption).
Married vs unmarried: two different rulebooks
Married or civil-partnered: the house is matrimonial property whoever’s named on it, the buyout usually happens inside the financial settlement, court orders can compel outcomes, and the SDLT exemption above applies. The wider machinery — Mesher orders, maintenance income, financial disassociation — lives in our divorce guide. Unmarried: there is no “common-law marriage” — ownership follows the deeds and any deed of trust, contributions don’t automatically create rights, and disputes fall under TOLATA (trust law), which is slower and less flexible than family court. Practical consequences: the deed of trust percentages are the starting price, not sentiment; a partner not on the deeds needs legal advice before assuming they’re owed anything (or owed nothing); and everything agreed should be documented, because informal understandings are exactly what TOLATA litigation is made of. If the person joining or staying on the mortgage has credit history to manage, our partner credit guide covers that dimension.
“My partner wants to buy me out” — the other side of the table
Half the people reading this page are the one leaving, so here’s your checklist:
- Value it yourself. Don’t accept their valuation — commission your own agent opinions or a RICS survey. On a £300,000 home, a 5% valuation gap is £7,500 of your money at 50%.
- Check the share before the price. Deed of trust? Its percentages govern. Contributions since (deposit, improvements, solo mortgage-paying months)? Raise them now, not after signing.
- Release from the mortgage is the whole deal. Coming off the deeds without coming off the mortgage leaves you liable for a house you no longer own — the worst position available. Completion should do both simultaneously; your conveyancer confirms the lender’s release in writing.
- Money moves through solicitors at completion — never sign the transfer against a promise to pay later (if a deferred deal is genuinely intended, it’s secured as a registered charge, drafted by your solicitor, not taken on trust).
- Your next chapter starts at release: until you’re off, the joint mortgage counts against your own borrowing power — which is why sequencing the release before your next purchase matters, and why a stalled release is worth escalating rather than tolerating.
If there’s no mortgage
The simplest version: no lender consent, no affordability gate — the buyout is a cash payment for their equity share, the conveyancer handles the TR1 and Land Registry, and SDLT applies only to the cash consideration (nil below £125,000; return still due at £40,000+; court-order transfers exempt as above). If you need to borrow against the mortgage-free home to fund the payment, that’s a standard purchase-style mortgage application on an unencumbered property — usually the easiest lending case on this whole page.
The bottom line
A buyout is a formula (equity × share), a gate (solo affordability on the new loan), a process (transfer of equity — quick and cheap by property standards), and two traps (chargeable-consideration stamp duty, and deed-release without lender-release). Both sides of the table do best with the same move: real numbers early — an honest valuation, the deed of trust read, and the affordability answer in hand before the conversation hardens.
Everything hangs on the mortgage question, so start there: compare mortgage deals and get the sole-name loan priced by a whole-of-market broker — free, no obligation, and before you negotiate a number you can’t fund.
Buying a partner out: FAQs
How does buying a partner out of a house work?
You agree a price for their share of the equity (property value minus mortgage, multiplied by their percentage), fund it — usually by remortgaging into your sole name for enough to clear the old loan and pay them — and complete a transfer of equity: a conveyancer moves the deeds to your name with the lender’s consent, your ex is paid through the solicitors and released from the mortgage, and the Land Registry records sole ownership. Typical timeline is four to eight weeks; typical legal cost £300–£800 plus Land Registry fees.
How do I calculate the buyout amount?
Value minus mortgage, times their share: a £300,000 home with £140,000 owing has £160,000 of equity, so a 50% buyout is £80,000 — or whatever percentage a deed of trust records if you own unequally. Use two or three agent valuations (or a RICS valuation for authority) rather than one person’s estimate, then negotiate adjustments both directions: deposits paid unequally, mortgage covered solo since separation, and the estate-agent and moving costs a sale would have cost you both — often 2–3% of the property’s value — that the buyout saves.
Do you pay stamp duty when buying a partner out?
Sometimes — and it catches people out. SDLT is charged on “chargeable consideration”: the cash paid for the share plus any existing mortgage debt you take over, with tax due above the £125,000 nil band and a return generally required from £40,000 of consideration even at zero tax. The big exemption: transfers made under a divorce or dissolution court order (or formal separation agreement) are SDLT-free entirely. Unmarried couples get no such exemption, and owning another property can trigger the additional-property surcharge on the whole consideration.
Can I buy my partner out if there’s no mortgage?
Yes, and it’s the simplest case: no lender consent or affordability test on the transfer itself — you pay cash for their equity share, a conveyancer completes the transfer of equity and Land Registry work, and stamp duty applies only if the cash consideration crosses the thresholds. If you need to borrow against the (now mortgage-free) home to fund the payment, that’s a standard mortgage application on an unencumbered property, which lenders generally find straightforward.
What if we can’t agree on the buyout figure?
Work the disagreement in order: valuation first (independent RICS valuation both sides accept in advance), then shares (the deed of trust governs if one exists; contributions evidence if not), then adjustments. If agreement still fails: married couples resolve it inside the financial settlement, where courts can order transfers or sales; unmarried co-owners fall under TOLATA, where a court can ultimately order sale — slower and costlier than agreeing, which is precisely the negotiating logic for both sides. Mediation before litigation is almost always money well spent.
When is my ex actually released from the mortgage?
At completion of the transfer of equity — when the lender formally removes them — and not before. The two dangerous half-states: staying on the mortgage after leaving the deeds (liable for a house they don’t own), and the remaining partner assuming a court order alone releases anyone (it doesn’t — the lender must approve, based on the stayer’s solo affordability). Until release, the joint mortgage also counts against the leaver’s own future borrowing, so both sides share an interest in completing the release properly and promptly.
- HMRC — SDLT on transfers of ownership: chargeable consideration, assumed debt and the divorce/dissolution exemption
- HM Land Registry — transfer of equity process and registration
- Conveyancing and legal market guidance — transfer of equity costs and lender consent practice, 2026
- TOLATA / family law guidance — unmarried co-ownership and deeds of trust
Important information
nextmove is an introducer, not a lender, adviser or law firm. This article is for general information only and does not constitute financial, legal or tax advice. Buyout valuations, ownership shares, stamp duty liability and transfer processes depend on individual circumstances and require professional legal and tax advice; lender criteria for sole-name affordability vary and change over time — all figures are indicative as of July 2026. We introduce you to FCA-regulated mortgage brokers who can advise on mortgages for your individual circumstances, and we may receive a fee or commission for doing so.
Your home may be repossessed if you do not keep up repayments on your mortgage.
Mortgages
Compare mortgage deals
Buyout maths done? Get the sole-name mortgage priced — whole-of-market, free.
Compare mortgage deals → Independent · No obligation