Shared Ownership Mortgage Affordability

Shared ownership affordability is assessed differently from a standard mortgage. The provider and a mortgage adviser look at the mortgage payment on the share you buy, plus the rent on the share you do not own, plus the service charge. Until August 2024 Homes England guidance capped those housing costs at 45% of net (take-home) household income. That cap has been replaced by a full budget check against each provider's minimum surplus income policy, so this calculator uses 45% of take-home pay only as a rough guide. Lenders also limit the mortgage, typically to about 4.5 times gross income. Because rent and service charges count too, the housing cost test often bites before the mortgage multiple does.

The calculator works out your take-home pay from 2026/27 income tax and National Insurance, then adds up three monthly costs for the share you pick: a 25-year repayment mortgage on the share price less your deposit (usually 5-10% of the share), rent at the rate you enter on the unsold share, and your service charge, which varies widely from one building to the next. For new-build homes rent is limited to 3% a year of the landlord's share, and the calculator defaults to 2.75%. It then tests the result against the 45% guide and the 4.5 times multiple, and tries every share from 10% to 75% at the same price and deposit to show the largest share that passes both.

You can buy through shared ownership in England if your household income is £80,000 or less (£90,000 in London) and you cannot afford the deposit and mortgage for a home that meets your needs. You must also be a first-time buyer, a former homeowner who cannot afford to buy now, forming a new household (for example after a relationship breakdown), an existing shared owner who wants to move, or a homeowner who cannot afford a home that meets your needs. Homeowners need a sale agreed on their current home and must complete it on or before the day they complete the shared ownership purchase. Some homes require a local connection, and serving members of the armed forces get priority when offers clash. You apply through the organisation selling the home, usually a housing association or council, which checks your eligibility and affordability.

Shared ownership carries costs that a headline affordability figure can hide. You pay for repairs and maintenance whatever share you own. Homes sold on the newer model lease have an initial repair period, usually 10 years, in which the landlord covers essential structural and external repairs and you can claim up to £500 a year towards repairs to boilers, radiators, pipes and similar fittings. Rent goes up each year: leases from before 12 October 2023 cap the rise at RPI plus 0.5%, while newer leases use either RPI plus up to 0.5% or CPI plus 1%. When you sell, the landlord first gets a nomination period of 4, 8 or 12 weeks to find a buyer. Lease length matters too: homes funded under the 2021-2026 Affordable Homes Programme have leases of at least 990 years, but older leases can be much shorter, and extending one that has fallen below 80 years is much more expensive.

Staircasing is the path to full ownership. You can usually buy extra shares of 10% or more at any time, and newer leases allow steps of 5% or more, priced from a RICS valuation, with a landlord administration fee of around £150 to £500. Homes sold on the newer model since April 2021 also let you buy 1% a year for the first 15 years, priced from the original price adjusted by the House Price Index, with no administration fee. In some protected rural areas you can only reach 80%. Stamp duty is not due on staircasing until your share goes above 80%, unless you paid it on the full market value at the start (a market value election), in which case nothing more is due. Legal and valuation fees come with every 5%-plus step, so fewer, larger purchases cost less in fees.