Joint Ownership Split Calculator
Work out a fair equity split when two buyers contribute different deposits, comparing the proportional method with returning deposits first.
💼 Are you a real estate agent or broker? Send this calculator to your buyers on your own branded listing page — every enquiry comes straight to your WhatsApp. Create free agent page →When two people buy together with unequal deposits, the split on sale is not obvious and is rarely agreed in advance. Two reasonable methods give different answers, and which one applies should be settled in writing before completion rather than argued about years later.
The proportional method treats each contribution as buying a percentage of the property. The deposit-first method returns each deposit before splitting the growth. Neither is more correct — but the difference is real money, and a declaration of trust or co-ownership agreement is what makes the choice binding.
The two methods
Proportional: each person contribution is their deposit plus their half of the mortgage, and the equity is divided in that ratio. Deposit-first: each deposit is returned in full, then whatever remains is split equally.
Worked example
A 400,000 purchase with A putting in 60,000 and B 20,000, and a 320,000 mortgage split equally. A contributed 220,000 of 400,000, or 55%. If it sells for 500,000 with 300,000 still owed, the equity is 200,000. Proportionally A takes 110,000 and B 90,000. Returning deposits first, A takes 120,000 and B 80,000 — a 10,000 difference on the same sale.
Put it in writing before completion
A declaration of trust or co-ownership agreement records the shares, who pays what, and what happens if one person wants out. Without it, the default position is set by local law and is frequently an equal split regardless of what each person actually contributed.
Turn a calculation into an enquiry
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Create your free property pageFrequently asked questions
Which method is fairer?
Neither is inherently fairer. Proportional treats the deposit as buying a share of the whole property, so it earns growth; deposit-first returns capital and splits only the gain. The one that is fair is the one both people agreed to in advance.
What if one person pays more of the mortgage?
Then the calculation should reflect it, because monthly payments build equity too. Record the arrangement in a co-ownership agreement, and revisit it if the payment split changes for a sustained period.
Do we need a formal agreement?
Strongly recommended. Without one, the split may default to whatever local law provides — often equal shares — regardless of unequal deposits. A declaration of trust drawn up at purchase costs little and prevents a very expensive dispute.