Stamp duty and the 'living together' test for married couples
Most people assume "living together" means sharing a home. For Stamp Duty Land Tax (SDLT), it does not. Under the rules for additional properties, a married couple or civil partners are treated as "living together" as a matter of law — automatically, from the day they marry or register the partnership — whether or not they have ever shared an address.
The consequence is easy to miss. When one half of a couple buys a home on their own, the tax rules look at what the other partner owns too. If that partner already owns a dwelling the couple are keeping, the solo purchase can be taxed as an additional property. On a home bought at the England median price of £290,000, that is the difference between a bill of £4,500 and one of £19,000 — an extra £14,500 that turns on marital status, not on where anyone actually lives (HMRC higher rates; HM Land Registry Price Paid Data, 833,817 England residential sales recorded in 2025, figures fetched July 2026).
The surcharge this hangs on
Since 31 October 2024, the higher rate of SDLT for additional dwellings has been 5 percentage points on top of the standard rate in every band, charged where a buyer ends the day owning an interest in more than one dwelling and the purchase is not simply replacing their only or main home (HMRC, buying an additional residential property, 2026). It applies to purchases of £40,000 or more — a floor that catches almost everything: 99.4% of England's 2025 residential sales (828,439 of 833,817) cleared it.
The mechanics of the surcharge are set out in our guide to the 5% additional-property surcharge. What is less widely understood is whose dwellings get counted.
"Living together" is a legal status, not an address
The additional-property rules live in Finance Act 2003, Schedule 4ZA. Paragraph 9 deals with a married person or civil partner who buys a dwelling on their own: where the couple are "living together" on the effective date, the spouse or partner is treated as a joint purchaser for the additional-property test. A dwelling the other partner owns anywhere in the world is therefore brought into the count, even though they are not a party to the purchase.
Everything then turns on the phrase "living together" — and here the statute departs sharply from everyday language. Paragraph 9(3) provides that married couples and civil partners are treated as living together unless:
- they are separated under an order of a court of competent jurisdiction;
- they are separated by a deed of separation; or
- they are separated in fact, in circumstances in which the separation is likely to be permanent.
This mirrors the long-standing income-tax definition at section 1011 of the Income Tax Act 2007, which uses the identical three-limb test across the tax system. The direction of the rule is the key point: "living together" is the default for anyone married or in a civil partnership. It is switched off only by a qualifying separation — never switched on by cohabitation.
Why "we have never lived together" is not a way out
Read the three exits closely and a pattern emerges: each one describes a couple coming apart. A court order separating them; a deed recording their separation; a factual separation likely to be permanent. All three presuppose a shared life to dissolve.
A couple who married but kept separate homes — a commuter marriage, one spouse posted to another city, two people who each held on to a property they already owned — have not "separated". There was no combined household to break up. Because none of the three limbs is met, the statute treats them as "living together", and paragraph 9 aggregates their dwellings. The intuition most buyers hold — that "living together" means sharing a roof, so not sharing one must mean not living together — runs exactly backwards.
The mirror image is just as counter-intuitive. Two unmarried people who genuinely share a home are not caught by paragraph 9 at all: the aggregation rule reaches only spouses and civil partners. So the law can treat a never-cohabiting married couple as one buyer while treating a long-cohabiting unmarried couple as two. "Living together", in this corner of the tax code, is a proxy for an ongoing marriage or civil partnership — the shared address is beside the point.
What it looks like at the median price
Consider a £290,000 purchase — England's median sale price in 2025. The figures below use HMRC's published rates; the standard and first-time-buyer results are confirmed by the stamp duty calculator.
| Buyer's position on the effective date | SDLT on £290,000 | Effective rate |
|---|---|---|
| Lone buyer, no other dwelling, first-time buyer | £0 | 0% |
| Lone buyer, no other dwelling, home mover | £4,500 | 1.55% |
| Buyer whose spouse/partner owns another dwelling that is being kept | £19,000 | 6.55% |
The £19,000 is the standard £4,500 plus a £14,500 surcharge — 5% of the whole £290,000. Nothing about the buyer's own finances changed between the second and third rows. The only difference is that a spouse or civil partner, treated as a joint purchaser, owns a dwelling somewhere — and the couple do not qualify as separated.
There is a first-time-buyer sting in the tail. First-time buyer relief is denied on any purchase that is an additional-property (higher-rates) transaction, so aggregation can knock out the relief and add the surcharge at once. The relief itself is explained in our guide to first-time buyer relief.
The exits that do work
The surcharge is not inevitable for every married buyer. Schedule 4ZA also contains a replacement exception (paragraph 3): a couple selling their old only-or-main residence and buying a new one are replacing, not adding, so the higher rates do not bite. And where a marriage or civil partnership genuinely has ended, one of the three paragraph 9(3) limbs can apply.
Whether a separation is "likely to be permanent" is the limb HMRC and the tribunals actually argue over — it is a question of fact, not a document you can wave. We cover the distinction in trial separation versus a permanent split, the evidence HMRC expects for a paragraph 9 separation, and, more broadly, how separation changes a couple's stamp duty. Notably, there is no "we were never together" limb — the only doors out are separation events.
The wider picture
The lesson generalises beyond couples who never cohabited. Because the additional-property test counts dwellings owned by a deemed-joint spouse anywhere in the world, a buyer's SDLT can depend on a property they have no interest in and may never have seen. Before committing, it is worth mapping the whole all-in cost of a purchase — SDLT is one line among several. You can see mortgage, council tax and energy costs for a real street with Homecost's true-cost tool, and browse more stamp duty and buying-cost guides for the neighbouring rules.
Based on 833,817 England residential sales recorded by HM Land Registry in 2025; see more of our data-led guides. Figures fetched July 2026. This is general information about how the rules work, not advice about any individual transaction, and the "living together" and separation tests turn on the facts of each case. Speak to a qualified adviser before acting.