Selling Your Home and Buying a New One: SDLT Guide
Standard home movers pay standard SDLT rates with no surcharge — provided the old home is sold on or before the new purchase completes. Timing matters enormously, as getting the order wrong triggers the 5% surcharge.
Last verified: April 2026
Key Takeaways
- •Selling your main home on or before the new purchase completion = standard SDLT rates, no surcharge.
- •Buying before selling = 5% surcharge applies, adding £20,000 on a £400,000 purchase.
- •The surcharge is fully refundable if the old home sells within 36 months of the new purchase.
- •At £400,000 a standard mover pays £10,000 — compared to £30,000 if they buy first.
- •Overseas properties follow exactly the same timing rules as UK properties.
In this article
Standard Mover Rules
A "standard mover" is someone who owns their main residence and is replacing it with another property. Provided the old home is disposed of (completion) on or before the date the new home is acquired, the additional dwelling surcharge does not apply. The buyer pays standard residential SDLT rates on the new purchase price, calculated in the usual way.
The relief from the surcharge applies automatically in this scenario — there is no need to claim it on the SDLT return. Your conveyancer will simply indicate on the return that the transaction replaces the purchaser's only or main residence, and standard rates are applied.
The "only or main residence" test requires that the old property was used as your main home. A property you owned as a buy-to-let that was never your main residence does not satisfy this test. If you own multiple properties, only the one genuinely used as your principal private residence qualifies.
Definition: "Main residence" follows similar principles to the Capital Gains Tax principal private residence exemption, though SDLT and CGT are assessed independently. Where there is any ambiguity, professional advice should be sought.
Timing Is Everything
The critical date comparison is between the completion of the old home's sale and the completion of the new home's purchase. The test is based on completion dates, not exchange dates.
Old home sold, THEN new home bought
Standard rates apply — no surcharge
Old and new home both complete on the same day
Standard rates apply — no surcharge
New home bought, THEN old home sold
5% surcharge applies — but refundable within 36 months
Property chains frequently collapse or cause completion-order reversals. If your sale falls through after you have already completed on the purchase, you immediately become subject to the surcharge. This is why conveyancers in chain transactions typically try to co-ordinate completions so that the sale occurs before or simultaneously with the purchase.
Worked Example at £400,000
Rachel sells her existing home and, on the same day, completes on a new home at £400,000. She qualifies as a standard mover replacing her main residence.
Standard Mover Calculation
| Band | Rate | Taxable Amount | Tax |
|---|---|---|---|
| £0 – £125,000 | 0% | £125,000 | £0 |
| £125,001 – £250,000 | 2% | £125,000 | £2,500 |
| £250,001 – £400,000 | 5% | £150,000 | £7,500 |
| Total SDLT (Standard Mover) | £10,000 | ||
Sells first → standard rates
£10,000
Buys first → higher rates
£30,000
Extra £20,000 (refundable)
If You Buy Before You Sell
When the new purchase completes before the old home is sold, you are treated as owning two residential properties at the effective date of the new purchase. The 5% additional dwelling surcharge therefore applies to the new purchase, calculated on the full purchase price from band 1.
Higher Rate Calculation at £400,000
| Band | Rate | Taxable Amount | Tax |
|---|---|---|---|
| £0 – £125,000 | 5% | £125,000 | £6,250 |
| £125,001 – £250,000 | 7% | £125,000 | £8,750 |
| £250,001 – £400,000 | 10% | £150,000 | £15,000 |
| Total SDLT (Buys Before Selling) | £30,000 | ||
Chain delay warning: If your property chain collapses and you end up completing on the purchase before the sale, you face an immediate £20,000 surcharge on a £400,000 purchase. This must be paid within 14 days of completion and then reclaimed from HMRC once the old home sells.
How to Claim a Refund
If you paid the surcharge because you bought before selling, you can apply for a refund of the surcharge component once the previous main residence has been sold. The following conditions must be met:
- The old home must be sold within 36 months of the effective date of the new purchase.
- You must not have acquired any further residential properties between the new purchase and the refund claim.
- You must have replaced your only or main residence — a buy-to-let does not qualify.
Refund Claim Process
- 1Complete the sale of your old main residence within 36 months.
- 2Locate your original SDLT transaction reference number (on the SDLT5 certificate).
- 3Submit a claim to HMRC within 12 months of selling the old home (or within 36 months of the new purchase, whichever is later).
- 4HMRC will verify the claim and issue a repayment of the surcharge portion only — the underlying standard SDLT is not refunded.
Frequently Asked Questions
What if I buy before I sell my old home?
You pay the 5% additional dwelling surcharge upfront — on a £400,000 property this adds £20,000 to the standard bill. You can claim a full refund of the surcharge within 36 months once the old home is sold, provided you have not purchased any further residential properties in the meantime.
My old home is abroad — does that affect things?
Yes. An overseas residential property counts for the additional dwelling surcharge in exactly the same way as a UK property. If you sell it after completing on your new home, the same 36-month window applies for claiming a refund of the surcharge.
What if my old home sale falls through after I have already completed?
You will need to pay the 5% surcharge on the new purchase and then sell the old home within 36 months of the new purchase completion to reclaim it. If the 36-month window closes before the old home sells, the right to reclaim the surcharge is permanently lost.
I am downsizing — is there any relief?
No specific downsizing relief exists within SDLT. Standard rates apply to the new purchase price regardless of whether you are moving to a smaller or larger property. The only relevant relief is the automatic absence of the surcharge when the old home is sold first.
Emma Richardson, MRICS
Chartered Surveyor & Property Tax Specialist
Emma Richardson is a RICS-qualified Chartered Surveyor with over 12 years of experience in UK property taxation. She founded Calculate My Stamp Duty UK to help buyers understand the complex world of property transaction taxes.
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