This is a specific but very common situation: you're buying a new main home, and your existing home hasn't sold yet. Whether you pay the 5% additional-property surcharge depends entirely on completion timing — not on the intent to sell, not on the fact that it's your main home. This page walks through the three scenarios, what SDLT applies to each, and how the reclaim works.

The three scenarios — and what each costs

Scenario 1 — Same-day sale and purchase (no surcharge)

Your sale and purchase complete on the same day. At the end of completion day, your total residential property count is unchanged (you swapped one main residence for another). No surcharge is due; standard SDLT rates apply. No reclaim needed. This is the cleanest route and about 60-65% of UK home movers achieve it.

Scenario 2 — Buy first, sell later (pay surcharge, then reclaim)

You complete the new purchase before selling your existing home. At completion, you own two properties — the surcharge is due. You pay it at completion, then reclaim the full amount once the old home sells within 36 months. About 30-35% of UK movers take this route.

Scenario 3 — Sell first, then buy (no surcharge)

You complete the sale of your existing home before completing the new purchase — you might rent short-term or stay with family in between. At the time of the new purchase you own zero residential properties. No surcharge is due; standard SDLT rates apply. Least common route (typically 5-10% of moves) because bridging accommodation is disruptive, but lowest-risk from a surcharge/cash-flow perspective.

SDLT figures by scenario — worked example at £500,000

Assume the new home is £500,000 and you have never bought before (main residence purchase; you already own your existing home).

Scenario	SDLT at completion	Refund	Net SDLT
1. Same-day (sell & buy same day)	£15,000	£0	£15,000
2. Buy first, sell within 36 months	£45,000	£30,000	£15,000
3. Sell first, then buy	£15,000	£0	£15,000
Scenario 2 but old home doesn't sell within 36 months	£45,000	£0 (deadline missed)	£45,000

Net SDLT is identical across the three normal-outcome scenarios — the surcharge is fully recoverable in Scenario 2. The only outcome that's meaningfully different is Scenario 2 with a failed sale — a £30,000 permanent cost premium at this price point.

The 36-month reclaim window — the deadline that matters

If you take Scenario 2 (buy first, sell later), you have 36 months from the effective date of the new purchase to complete the sale of your previous main residence. Effective date is usually the completion date.

Miss this window and the reclaim is permanently lost — HMRC does not grant extensions except in narrow special circumstances (compulsory purchase orders, specific hardship cases).

Once the sale completes within the window, you then have 12 months from the sale date to file the reclaim (or 12 months from the original SDLT return filing, whichever is later). Filing is straightforward via HMRC's online refund tool.

See the dedicated SDLT surcharge refund calculator for your specific reclaim amount and deadline dates.

Which scenario is right for you?

Choose Scenario 1 (same-day) if:

• You have a solid buyer for your existing home who can align on timing
• Your chain is short and predictable
• You want to avoid the cash-flow hit of the surcharge
• You don't need extended time to renovate before moving

Choose Scenario 2 (buy first) if:

• You've found a property you don't want to lose to another buyer
• You can fund the surcharge as a temporary cash-flow item (typically £20k-£60k)
• Your existing home is likely to sell within 36 months at a realistic asking price
• You want time to renovate the new home before selling the old one

Choose Scenario 3 (sell first) if:

• You're comfortable with short-term rental or family accommodation between sales
• You want to know your budget precisely (cash from sale determines what you can buy)
• You're in no rush — the "buy first" opportunity cost of waiting doesn't apply
• You want zero SDLT surcharge risk regardless of market conditions

Cash flow — Scenario 2 in detail

The surcharge on a mainstream family-home purchase is substantial:

New home price	Surcharge to fund at completion
£300,000	£15,000
£400,000	£20,000
£500,000	£30,000
£600,000	£30,000
£750,000	£45,000
£1,000,000	£50,000

This cash sits with HMRC until the old home sells and the reclaim is processed (typically 15 working days after filing). Practical funding sources:

• Cash reserves — cheapest, no interest cost
• Bridging loan — 8-15% APR typical for short-term (up to 12 months) property bridges; adds material cost but useful if reserves are tight
• Higher-LTV mortgage on the new home — some buyers take a bigger mortgage on the new home to preserve deposit cash for the surcharge, then reduce the mortgage via overpayment once the reclaim arrives
• Family loan — sometimes used where extended family can lend at zero or low interest

Scenario 2 — what if the old home doesn't sell?

This is the risk. Options if you're approaching the 36-month deadline without a completed sale:

1. Cut the asking price aggressively. A 10-15% price reduction to complete inside the deadline is almost always worth it — the refund is typically 6-10% of the new home's price, so preserving it usually justifies a meaningful price cut on the old home.
2. Auction the property. Modern method of auction (28-day exchange) can complete inside 8 weeks. Traditional auction faster still. Both accept the reality of a lower price for guaranteed timing.
3. Sell to a cash home-buyer. Companies like WeBuyAnyHome, Property Solvers etc. buy in weeks for 70-80% of market value. Only worth it if the deadline is imminent and no other route works.
4. Accept the permanent surcharge. If the old home is worth keeping (rental income, capital appreciation, family reasons) and the reclaim is genuinely not recoverable, treat the surcharge as a permanent cost of that decision.

Non-UK-resident buyers — extra layer

If you're non-UK-resident under the SDLT 183-day test, an additional 2% surcharge applies on top of everything else. On a £500,000 new-home purchase in Scenario 2 (buy first, old-home-still-selling):

• Standard SDLT: £15,000
• Additional-property surcharge: £30,000 (reclaimable when old home sells)
• Non-UK-resident surcharge: £10,000 (reclaimable if you become UK-resident within 12 months of completion)
• Total at completion: £55,000
• Two independent reclaim paths available.

See the non-resident SDLT surcharge calculator for the 2% reclaim path.

Special situations

Divorce or separation

Where a separating spouse buys a new home before the marital home is sold, the surcharge normally applies at completion because both spouses still own the marital home. Court orders under matrimonial legislation can remove ownership before the new purchase completes, avoiding the surcharge. Take specialist advice.

Overseas main residence

If your existing main residence is overseas and you're buying in the UK, the surcharge applies at completion because you already own another residential property (the overseas home). The replacement-of-main-residence path requires you to sell the overseas home within 36 months of the UK purchase — same rules, worldwide scope.

Inherited property

Inherited property is disregarded for the surcharge if your share is 50% or less AND the new purchase is within 3 years of inheritance. Above either threshold, the surcharge applies. See our inherited-property surcharge FAQ for detail.

Practical timeline planning

A realistic UK home-move sequence for Scenario 1 (same-day):

1. Offer accepted on new home; existing home listed within days.
2. Existing home under offer within 4-8 weeks typical.
3. Both chains progress simultaneously — conveyancers coordinate.
4. Chain aligns on exchange date around week 10-14 of the transaction.
5. Exchange completes; completion date set 7-21 days later.
6. Same-day completion: sale funds arrive, purchase funds go out simultaneously.
7. Move-out and move-in happen on the same day.

Most UK conveyancers manage this routinely. Where the chain is complex (5+ links), the same-day route becomes harder to achieve and Scenario 2 becomes more likely.

Frequently asked questions

Do I pay the extra 5% surcharge if I'm selling my first home?

Depends on timing. Same-day sale & purchase: no surcharge. Buy first, sell later: surcharge due at completion, reclaimable within 36 months.

How does a same-day exchange work?

Both transactions complete on the same day. Sale funds arrive as purchase funds go out. Standard UK conveyancer coordination. Small premium (£100-£200) for extra coordination.

How long to sell the old home to reclaim?

36 months from new-home completion. Then 12 months from sale to file the reclaim. Both strict.

What if the sale of my old home falls through?

Surcharge remains payable. Relist promptly; drop price aggressively if approaching 36-month deadline. Missing the deadline makes the surcharge permanent.

Can I move into the new home before selling the old one?

Yes — that's the standard "buy first" pattern. Rent out the old home while it's for sale if you want; doesn't affect the reclaim as long as it was genuinely your main residence in the last 3 years.

What if I never sell the old home?

Surcharge becomes permanent after 36 months. Old home is classified as your additional property from that point.

How is the surcharge calculated?

5% surcharge stacks band-by-band. On £500k: 5%×£125k + 7%×£125k + 10%×£250k = £40k total; £30k of that is the reclaimable surcharge element.

Does this apply to buy-to-let purchases?

No. Reclaim only applies to replacement-of-main-residence. BTL surcharge is permanent — no reclaim path.

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Last reviewed: 21 August 2026. Guidance only — always confirm SDLT with your conveyancer.