Buying with a partner when the deposits are unequal

What happens to an unequal deposit without a tenancy in common?

It can become half the other person's. Where two names go on the register of a home you bought to live in together, and nothing records the shares, the starting point is that you own it jointly in equity as well as at law, so the survivor would take the whole on a death and on a separation neither of you starts with a larger share to point to. The person who paid more has to prove that you both intended something different, and unequal deposits alone do not prove it (Jones v Kernott [2011] UKSC 53, checked 20 September 2026). If the transfer already declares how you hold the property beneficially, that declaration governs instead and settles it. Emails from the time, the bank statement showing the deposit and the fact that everyone knew are all evidence, and all of it is argued over in court years later. Settling for less than the deposit can cost less than running that case.

A joint tenancy makes it worse. Joint tenants have no shares at all, so on the death of the partner who paid the deposit the whole property passes to the survivor, and that partner's family sees nothing of the money. A tenancy in common is what gives each of you a share to own, and the deed is what says how big the share is. The tenants in common entry explains the register wording; the joint tenants vs tenants in common page sets the two side by side.

How should a tenancy in common in unequal shares be calculated?

There are three ways, and the choice depends on what you want to protect. The first is fixed percentages: the deposits and the mortgage are added up, each partner's share is worked out as a percentage of the whole, and that percentage is applied to the net proceeds on sale. It is simple, and nothing has to be recalculated when the value moves. One point to check with your figures: where the mortgage is counted as contributed equally, because you are each liable for all of it, the partner with the larger deposit can end up with a smaller percentage than they expect.

The second is deposit back as a sum. On sale, each partner gets their deposit back first, then the balance is split equally. It returns the money exactly, and the deposit does not share in any rise in value. If prices fall, the deposit is paid back out of a smaller pot and the other partner can end up with nothing or less than nothing, which the deed has to address.

The third is deposit back as a percentage. Each deposit is expressed as a percentage of the price paid, and that percentage of the net proceeds comes back to its contributor before the equal split. A deposit of a fifth of the price returns as a fifth of what the property fetches, up or down. It moves with the market in both directions. We have no default among the three: we set out each route against your figures and your plans, and you choose the one that fits.

Does the mortgage change how unequal shares work?

The mortgage is a joint and several debt: the lender can pursue either of you for all of it, whatever the deed says about shares. The deed cannot change that. What it can do is say how the mortgage counts between the two of you. In a deposit-back deed the usual position is that the mortgage is treated as contributed equally, because you are each liable for the whole, and the balance after the deposits is split equally. Where one partner will pay more of the monthly payments, an optional clause can credit the extra payments as capital. It is an add-on that works with any of the three structures, not a fourth structure, and whether to include it is your choice: there is no default. How that is worked, and whether interest as well as capital counts, is a matter of drafting rather than of law, so the deed has to say it in terms: no rule supplies the answer if the deed is silent.

Lenders rarely need to approve a deed between the two borrowers, but a gifted deposit is different. The lender will normally have required the donor to sign a letter confirming the money is an outright gift and that the donor claims no interest. There is no single published industry standard for that letter: each lender sets its own requirement, answered in part 2 of that lender's entry in the UK Finance Mortgage Lenders' Handbook, so the wording to use is the wording your lender asks for. The deed must not describe that money as a loan from the parents, or as buying the parents a share, because that contradicts what the lender was told. It can, and should, say that the gift was made to one partner and is credited to that partner alone.

What if we split up after buying with unequal deposits?

The deed answers it in advance. It says who can require a sale and after how much notice, whether the other partner can buy them out first, how the price is fixed if they do, and how the net proceeds are divided. With those clauses in place a separation is arithmetic and a valuation, not litigation. Without them, an unmarried partner who wants out applies to court under section 14 of the Trusts of Land and Appointment of Trustees Act 1996, and a judge decides, on evidence and years later, the questions the deed could have answered on the day you bought. Note what that court cannot do: it cannot compel either of you to buy the other out. Under section 14 it can order a sale or declare what the shares already are, and it can order a sale that gives one owner the first opportunity to buy at a value the court sets (Bagum v Hafiz [2015] EWCA Civ 801, checked 26 September 2026). The deed sets those terms in advance, on terms the two of you chose rather than terms a judge imposes.

If one of you dies instead, the tenancy in common means your share goes under your will. That is the reason to make a will at the same time. Without one the intestacy rules apply, and an unmarried partner is not on the list, so the share the deed protected goes to your parents or siblings rather than the person you lived with. A single will each, or mirror wills, leaves the share where you want it.