Shared Ownership Calculator

Shared ownership is a UK government-backed part-buy, part-rent scheme designed to help buyers who cannot afford to purchase outright. You buy a share of a property — typically between 25% and 75% — from a housing association and pay a subsidised rent on the remaining portion. You take out a standard residential mortgage on your share, which is smaller and more affordable than a full purchase mortgage, and over time you can "staircase" — buy additional shares — until you own 100%. This calculator models all three costs that make up your monthly housing bill under shared ownership: the mortgage on your share, the monthly rent on the remaining share, and the service charge. Because shared ownership properties are always leasehold, a monthly service charge covering building maintenance, communal areas and building insurance is unavoidable — and it can be significant, typically £100–£400/month in cities. The SDLT (Stamp Duty Land Tax) figure uses the market-value election — you pay SDLT on the full property value upfront, which avoids further SDLT liability when you later staircase. First-time buyers benefit from FTB relief: 0% on the first £300,000 and 5% from £300,000–£500,000. On properties above £500,000 the standard England SDLT bands apply. The rent on the remaining share is set by the housing association in your lease. It is expressed as an annual percentage of the unsold share value — typically 2.75% — and is reviewed periodically (usually annually by RPI or a fixed percentage cap set in the lease). This means as house prices rise, if your rent is linked to current value rather than original value, your rent can increase substantially. Always check your lease terms. The staircasing section shows what happens if you buy an extra 10% share. Note that each staircasing transaction requires a new RICS valuation and legal fees (typically £1,000–£2,000 per transaction), the property must be valued at current market price, and SDLT applies on the share purchased if you opted for deferred SDLT on initial purchase. Buying shares in larger tranches (20–25% at a time) saves on transaction costs. Shared ownership is available through housing associations and Help to Buy agents. Eligibility is means-tested: your household income must generally be below £80,000 (£90,000 in London). You must be unable to purchase a suitable home outright. This scheme is only available in England; Scotland has the Low-cost Initiative for First-Time Buyers (LIFT) and Wales has its own Help to Buy scheme.