Shared ownership mortgage calculator
This shared ownership mortgage calculator works out the mortgage, deposit, rent and monthly costs for buying a share of a home in England. You can also see what staircasing to a bigger share would cost and how much stamp duty you might pay.
Rules last checked 13 October 2026.
GOV.UK says the deposit is usually between 5% and 10% of the share you are buying.
Use a rate from your lender or broker. This is an example, not a quote.
GOV.UK says most landlords charge 2.75% on new-build homes, and the limit for new-build homes is 3%. For resale homes the starting rent matches what the previous shared owner paid.
For example estate charge, management fee or repairs reserve (sinking fund) contributions, which GOV.UK says may apply.
Uses the choices on the Stamp duty tab.
Optional eligibility check
Estimated total monthly cost
£1,092.27
For comparison: monthly mortgage payment if you bought the whole home with the same deposit percentage and no rent: £1,449.42.
- Share value
- £120,000.00
- Deposit
- £12,000.00
- Mortgage amount
- £108,000.00
- Monthly mortgage payment
- £579.77
- Monthly rent
- £412.50
- Service charge
- £100.00
- Ground rent
- £0.00
- Other costs
- £0.00
- Total a month
- £1,092.27
- Upfront cash (deposit)
- £12,000.00
Rent can rise at review but not fall. For leases signed before 12 October 2023 increases are capped at RPI plus 0.5%. For leases signed on or after that date the cap is RPI plus up to 0.5% or CPI plus 1%, depending on your lease. Increases are not modelled here.
- ✓ Your share is within the 10% to 75% range.
These are hints only. Read who can apply for shared ownership on GOV.UK.
Show the working
- Share value: £300,000.00 × 40% = £120,000.00.
- Deposit: £120,000.00 × 10% = £12,000.00. Mortgage: £120,000.00 − £12,000.00 = £108,000.00.
- Monthly mortgage: £108,000.00 repaid over 30 years at 5% = £579.77.
- Rent: £300,000.00 × 60% (landlord's share) × 2.75% ÷ 12 = £412.50.
- Total: £579.77 + £412.50 + £100.00 + £0.00 + £0.00 = £1,092.27.
- Comparison: £270,000.00 repaid over 30 years at 5% = £1,449.42.
Nothing you enter leaves your device. Not mortgage or financial advice. Speak to a regulated mortgage adviser. Your home may be repossessed if you do not keep up repayments on your mortgage.
How shared ownership works
With shared ownership you buy a share of the home, between 10% and 75% of its full market value, and pay rent to the landlord on the share you do not own. All shared ownership homes are leasehold, so you usually also pay ground rent and a service charge. Later you can buy more shares, which is called staircasing.
Shared ownership mortgage: how the numbers work
Your mortgage is only on your share of the home. The share value is the full market value times your share. Your deposit is a percentage of that share value, and the mortgage covers the rest. Rent is worked out on the landlord's share.
For example, on a £300,000 home a 40% share is worth £120,000. A 10% deposit is £12,000, so the mortgage is £108,000. At 5% over 30 years that is £579.77 a month. Rent at 2.75% on the landlord's 60% share is £412.50 a month. With a £100 service charge the total is £1,092.27 a month.
Lenders assess your income and outgoings before deciding what to lend.
| Share | Share value | Deposit | Mortgage needed | Monthly rent |
|---|---|---|---|---|
| 25% | £75,000 | £7,500 | £67,500 | £515.63 |
| 40% | £120,000 | £12,000 | £108,000 | £412.50 |
| 50% | £150,000 | £15,000 | £135,000 | £343.75 |
| 75% | £225,000 | £22,500 | £202,500 | £171.88 |
Shared ownership rent
On new-build homes most landlords charge 2.75% a year of the value of their share, and the limit is 3%. For resale homes the starting rent matches what the previous shared owner paid.
Rent is reviewed on dates set in your lease, usually once a year. It can rise but not fall. For leases signed before 12 October 2023 increases are capped at RPI plus 0.5%. For leases signed on or after that date the cap is RPI plus up to 0.5% or CPI plus 1%, depending on your lease.
Because rent is based on the landlord's share, it falls as you buy more shares.
| Share owned | Landlord share | Monthly rent |
|---|---|---|
| 25% | 75% | £515.63 |
| 40% | 60% | £412.50 |
| 50% | 50% | £343.75 |
| 75% | 25% | £171.88 |
| 100% | 0% | £0.00 |
Buying 10% more at a £300,000 valuation would cost £30,000.
Who can apply
Your household income must be £80,000 a year or less, or £90,000 or less in London. You must also be unable to afford all of the deposit and mortgage payments for a home that meets your needs. You must be one of these:
- a first-time buyer
- someone who used to own a home but cannot afford to buy one now
- forming a new household, for example after a relationship breakdown
- an existing shared owner who wants to move
- someone who owns a home, wants to move and cannot afford a new one
Some homes need a local connection. If you own a home, the sale must complete on or before the day you complete your purchase.
Other schemes
If you are 55 or over, Older Persons Shared Ownership lets you buy up to 75%, with no rent on the remaining 25%. HOLD (Home Ownership for people with Long-term Disabilities) helps disabled people. Members of the armed forces get priority. This calculator does not model these schemes.
| Rule | What GOV.UK says |
|---|---|
| Share you can buy | 10% to 75% of market value (usually 25% to 75%) |
| Deposit | Usually 5% to 10% of the share |
| Rent | On the share you do not own (most landlords 2.75%, limit 3% for new-build) |
| Tenure | Leasehold |
| Household income | £80,000 or less (£90,000 or less in London) |
| Reservation fee | Up to £500 |
| Maximum ownership | Usually 100% |
Staircasing: buying more shares
You can buy more shares in your home. For shares of 5% or more, the price depends on the home's value when you buy, and you must buy within 3 months of the RICS valuation date. You pay your own legal fees and the valuation, and the landlord may charge an administration fee of roughly £150 to £500.
The smallest share you can usually buy at a time is 10%. Older leases may only allow 25% or more, and some newer leases allow 5% or more. If you bought on or after 1 April 2021 you may be able to buy 1% shares, one a year for the first 15 years. You cannot buy 2%, 3% or 4% shares. There is no admin fee for 1% shares.
The maximum you can own is usually 100%. In designated protected areas it is 80%, and for Older Persons Shared Ownership it is 75%.
Costs on top of the mortgage and rent
- Your deposit.
- A reservation fee of up to £500. It is taken off the final amount on completion day and is usually not returned if you do not buy.
- Legal fees.
- Stamp duty, if it applies.
- Buildings insurance once you own the home.
- A repairs reserve fund (sinking fund), which you usually cannot get back.
- An estate charge and management fee on some homes.
Stamp duty on shared ownership
You can make a one-off payment based on the market value of the whole home, even though you are buying a share. After that you pay no more stamp duty when you buy more shares. For example, a 50% share of a £280,000 property costs £4,000 in stamp duty on this route. First-time buyer relief may reduce the tax.
Or you can pay in stages. You first pay tax on the price of your share if it is above £125,000, and you still submit a return if it is not. You may also pay 1% on rent over the lease above the threshold. You pay no stamp duty or return on later shares until you own more than 80%.
| Market value | Standard rates | First-time buyer |
|---|---|---|
| £200,000 | £1,500 | £0 |
| £250,000 | £2,500 | £0 |
| £280,000 | £4,000 | £0 |
| £300,000 | £5,000 | £0 |
| £400,000 | £10,000 | £5,000 |
| £450,000 | £12,500 | £7,500 |
| £500,000 | £15,000 | £10,000 |
| £600,000 | £20,000 | £20,000 (relief not available) |
About this calculator
Last reviewed 13 October 2026. It assumes a repayment mortgage with a fixed rate for the whole term and rent at a fixed percentage of the landlord's share. It does not model rent increases, Older Persons Shared Ownership, HOLD, staged rent stamp duty, higher rates for additional homes or the non-UK resident surcharge. Read how we check and review our calculators.
Frequently asked questions
How does a shared ownership mortgage work?
You take out a mortgage to buy your share of the home, which is between 10% and 75% of its full market value, and pay rent to the landlord on the rest. Your deposit is usually between 5% and 10% of the share you are buying. Lenders assess your income and outgoings.
How much deposit do I need for shared ownership?
GOV.UK says the deposit is usually between 5% and 10% of the share you are buying, not of the whole home. For a 40% share of a £300,000 home, a 10% deposit is £12,000.
How is shared ownership rent calculated?
Rent is based on the landlord's share, meaning the part of the home you do not own. On new-build homes the limit is 3% of the value of the landlord's share and most landlords charge 2.75%. For resale homes the starting rent matches what the previous shared owner paid.
Can shared ownership rent go up?
Yes. Rent is reviewed on dates set in your lease, usually once a year, and it can rise but not fall. For leases signed before 12 October 2023 increases are capped at RPI plus 0.5%. For later leases it is RPI plus up to 0.5% or CPI plus 1%, depending on your lease.
What is staircasing?
Staircasing means buying more shares in your home. Because rent is based on the landlord's share, you pay less rent as you buy more. The smallest share you can usually buy at a time is 10%, and some leases allow 1% shares.
What is the income limit for shared ownership?
Your household income must be £80,000 a year or less (£90,000 or less in London), and you must be unable to afford all of the deposit and mortgage payments for a home that meets your needs.
Do I pay stamp duty on shared ownership?
You may need to. You can either make a one-off payment based on the full market value of the property, even though you are buying a share, or pay in stages. If you choose the one-off payment you pay no more stamp duty when you buy more shares later. For example, a 50% share of a £280,000 property costs £4,000 using the market value route.
Is shared ownership leasehold?
Yes. All shared ownership homes, houses and flats, are leasehold properties, and you usually also pay monthly ground rent and service charges.
Can I own 100% of a shared ownership home?
Usually yes, by staircasing. The maximum is usually 100%, but it is 80% in designated protected areas and 75% for Older Persons Shared Ownership homes. Some homes have a waiting period before you can buy more shares, so check your lease.
Is this shared ownership mortgage calculator a mortgage quote?
No. It estimates your monthly costs from the figures you enter. Your actual mortgage depends on your lender's assessment, so speak to a mortgage adviser.
Sources
Checked 13 October 2026:
Browse all UK calculators.
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