How to use the shared ownership calculator
- 1 Enter the full market value of the home and the share you plan to buy.
- 2 Enter your deposit as a percentage of your share, the mortgage rate and the term.
- 3 Check the rent percentage on the unowned share and add the service charge.
- 4 Read the total monthly cost and the staircasing figures.
Worked example
A £300,000 home, buying a 40% share with a 10% deposit and a 4.8% 30-year mortgage. The share costs £120,000, so the deposit is £12,000 and the mortgage £108,000, which is £566.64 a month. Rent of 2.75% on the unowned £180,000 is £412.50 a month, and with a £120 service charge the total is £1,099.14 a month.
Making shared ownership work
- Look at the total: mortgage, rent and service charge together.
- Rent rises every year, often with inflation.
- Staircase when you can: each extra share cuts your rent.
- Check repair rules in the lease before you buy.
Check what you could borrow with the Mortgage Affordability Calculator and plan overpayments with the Mortgage Overpayment Calculator.
Features
True monthly cost
Mortgage, rent and service charge together.
Deposit and mortgage
Based on the share, not the full price.
Staircasing
The cost of another 10% and the rent it saves.
When to use it
First-time buyers
See whether shared ownership is affordable on your income. For a normal purchase, use the Mortgage Affordability Calculator.
Comparing with renting
Compare the monthly total with your current rent.
Planning to staircase
See how buying more shares reduces rent. For overpaying the mortgage, use the Mortgage Overpayment Calculator.
Budgeting the move
Add Stamp Duty with the Stamp Duty Calculator if it applies.
Related Home and Auto tasks
Frequently asked questions
How does shared ownership work?
You buy a share of a home, usually between 10% and 75%, with a mortgage and deposit on that share, and pay rent to the housing association on the rest. You can buy more shares later, called staircasing.
How much rent will I pay?
Usually up to 2.75% a year of the value of the share you do not own, paid monthly. On a £300,000 home with a 40% share, the unowned £180,000 costs about £412.50 a month. Rent normally rises each year with inflation.
What deposit do I need?
Usually 5% to 10% of your share, not the full value. For a 40% share of a £300,000 home, that is £6,000 to £12,000.
What is staircasing?
Buying more of your home. New-model leases let you buy as little as 1% a year for the first 15 years with low fees, or larger steps of at least 5%. Each share is priced at the home's value at the time.
Do I pay service charges?
Yes. Most shared ownership homes are leasehold flats or houses with service charges and sometimes ground rent, even if you own only part.
Who is eligible?
In England, households earning £80,000 or less (£90,000 in London) who cannot afford to buy outright, usually first-time buyers or people who used to own a home.
Do I pay Stamp Duty?
You can pay it on your share only, or elect to pay it on the full value at the start. First-time buyer relief may apply. Use the Stamp Duty Calculator for the figures.
Who pays for repairs?
Under the new model, the landlord covers essential repairs for the first 10 years of a new home. Otherwise shared owners usually pay for repairs and maintenance in full.
Can I sell my share?
Yes, but the housing association usually has a period to find a buyer first. You sell your share at its current market value.
Results are estimates based on the official rates linked above. Confirm important figures with the issuing authority or a qualified adviser before you act on them.
Built and reviewed by Hamza Farooq, founder and lead developer
· Last updated
· How we check our tools
· Report a problem