Stamp duty when a married couple is buying
For SDLT, a married couple or civil partnership is treated as a single household. One spouse's existing property counts when assessing the additional-property surcharge on the other's new purchase, and both buyers must qualify for first-time buyer relief if it is to apply.
Last reviewed 16 May 2026.
The "one unit" rule
SDLT treats spouses and civil partners living together as one person for the purposes of counting properties owned. This applies to:
- the additional-property surcharge
- first-time buyer relief
- the replacement-of-main-residence test
The rule applies whether you are on the new deed jointly or not. Even if only one of you is legally buying, the other's existing property ownership counts.
First-time buyer relief and married couples
Both spouses must qualify for FTB relief for it to apply, regardless of which of you is on the deed. If your spouse has ever owned property anywhere in the world, FTB relief is not available on a joint purchase. The same is true if only the FTB-qualifying spouse is named on the new purchase, HMRC treats the household together, so the relief is still denied.
The only case where FTB relief survives a marriage is if you and your spouse have genuinely been separated for so long that you are no longer "living together" for the legal test. Take advice, the bar is high and the consequences of getting it wrong are material.
The additional-property surcharge for couples
If you are married and your spouse owns a residential property worth more than £40,000, a new purchase by either of you almost always attracts the 5% surcharge. This catches a common scenario: one spouse owned a property before the marriage and the other is now buying their first home together. The 5% surcharge applies to the joint new purchase.
The household has one main residence between them. If they are replacing that main residence - selling one home and buying another in joint names, the surcharge does not apply provided both transactions complete on the same day. If the new home completes before the old one sells, the surcharge applies and is reclaimable on the eventual sale.
Buying in one spouse's sole name
Some couples consider buying only in the FTB spouse's name, hoping to preserve relief. This does not work. HMRC treats spouses living together as a single unit, so the non-qualifying spouse's history is imputed to the qualifying spouse for SDLT purposes.
The surcharge follows the same logic: even if only one of you is named on the new purchase, if the other spouse owns property elsewhere, the surcharge applies.
Separation and divorce
If you are formally separated under a court order or have lived apart on a permanent basis, the "one unit" rule no longer applies. From the point of formal separation, each spouse's property history is assessed independently. The matrimonial home itself, however, may need to be transferred or sold for either party to make a clean new purchase. See SDLT on divorce.