Shared Ownership Calculator

Calculate the total monthly cost of a shared ownership property. Shows your mortgage, rent on the remaining share, and service charge side by side for any share percentage.

Last updated: April 2026

Shared ownership details
Minimum share is typically 10–25% depending on the scheme.
Typically 5–10% of your share value, not the full property.
Rent on unsold share
Typically 2.75–3% of the value of the share you do not own.
Service charge
Shared ownership costs
Total monthly cost
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Your share value -
Mortgage amount -
Monthly mortgage -
Monthly rent (to housing assoc.) -
Monthly service charge -
Stamp duty (first-time buyer) -

How shared ownership works

Shared ownership allows you to buy a share of a property (typically between 25% and 75%) and pay subsidised rent on the remaining share to a housing association. You need a mortgage only on the share you are buying, which means a smaller deposit and lower mortgage payments than buying outright. The rent on the remaining share is set at a below-market rate, typically 2.75–3% of the value of the share you do not own per year.

Staircasing

Staircasing is the process of buying additional shares over time, increasing your ownership percentage. Most shared ownership properties allow you to staircase in 5–10% increments, each time paying the current market value of that share (not the original price). Once you reach 100% ownership, you own the property outright and no longer pay rent. Each staircasing transaction incurs legal fees and potentially stamp duty, so the financial benefit of staircasing depends on how property values have moved and your personal circumstances.

Service charges and ground rent

Shared ownership properties are almost always leasehold, meaning you pay a service charge for maintenance of communal areas and building insurance. Service charges vary enormously - from £50 per month in a small block to £400+ per month in a managed development with concierge, gym, or significant communal facilities. Always check the service charge history and any scheduled major works before purchasing. Ground rent was banned on new leases from June 2022, but older shared ownership leases may still have ground rent clauses.

Frequently asked questions

Shared ownership is available to first-time buyers, those who previously owned but cannot now afford to buy, and existing shared owners who want to move. There is a maximum household income threshold of £80,000 per year (£90,000 in London). You must not currently own a home. Some shared ownership schemes prioritise key workers or local connection applicants. In England, properties must be purchased through a registered provider (housing association). Scotland, Wales and Northern Ireland have their own equivalent schemes.
Yes, but with restrictions. If you have not reached 100% ownership, you must typically offer the housing association the right of first refusal - they have 8 weeks to find a buyer at the current market value before you can market it on the open market. This can slow down the sales process. Buyers must meet the same eligibility criteria as the original purchaser. Once you own 100%, you can sell on the open market freely. The process of selling a shared ownership property is more complex than a standard freehold sale.
Shared ownership provides access to homeownership for buyers who cannot afford to purchase outright in their area. The total monthly cost (mortgage + rent + service charge) is often comparable to or slightly higher than renting in the same area, but with the benefit of building equity in your share. The key financial risk is that rent and service charges can increase, and staircasing when prices have risen can be expensive. It is best suited to buyers with a clear plan to staircase over time in an area with good long-term growth prospects.

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