Shared Ownership Calculator
Use this shared ownership calculator to estimate your monthly cost. Enter the full property value, the share you plan to buy, your deposit percentage, and the rent and service charge assumptions to see an estimated monthly total.
Mortgage settings
Total monthly cost
£760.00
Monthly mortgage£330.00
Monthly rent£430.00
Service charge£0.00
Share value£62,500.00
Deposit amount£3,125.00
Mortgage amount£59,375.00
Remaining share value£187,500.00
Effective rent rate2.75%
Total monthly cost includes your estimated mortgage payment on the share you’re buying, plus rent on the remaining share, plus any service charge you enter.
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Copy a link that keeps your current numbers, so you can come back later or send it to someone.
How this shared ownership calculator works
Shared ownership usually means you buy a percentage of the property and pay rent on the remaining share.
- Share value: property value × share percentage.
- Deposit: a percentage of the share value.
- Mortgage amount: share value minus deposit (repayment mortgage estimate).
- Rent: based on the remaining share value and your rent rate.
- Total monthly cost: monthly mortgage + monthly rent + service charge.
Example model (default scenario)
This shows the default scenario when the page loads. It stays the same as a quick sanity check.
Share value£62,500.00
Mortgage amount£59,375.00
Total monthly cost£760.00
Important
This calculator gives a simplified estimate. Your provider’s rent rate, service charge, and fees can vary.
Mortgage payments are estimates and depend on your lender, product, and personal circumstances.
How it works
Shared ownership is a way to buy a share of a property and pay rent on the remaining share owned by the provider (often a housing association). This calculator estimates an illustrative monthly total made up of:
- Mortgage payment on the share you buy (after your deposit).
- Rent on the share you do not own (based on a rent rate assumption).
- Service charge (a monthly figure you enter).
GOV.UK explains that you typically buy between 10% and 75% and you’ll usually pay a 5% to 10% deposit on the share you’re buying (scheme/provider rules vary).
Important: this is guidance only. Actual rent, service charges, eligibility, and lender affordability rules depend on your provider and lender.
Rates and thresholds
Last verified: 04/03/2026. Primary source: GOV.UK shared ownership scheme. Related: GOV.UK leasehold service charges and other expenses.
- Share size: GOV.UK notes you typically buy between 10% and 75% of the full market value (and some homes allow 10%). Providers can set their own ranges.
- Deposit: GOV.UK notes a deposit is usually 5% to 10% of the share you’re buying (provider and lender rules vary).
- Rent: providers set rent on the unowned share. Offers often express rent as a percentage of the provider’s share per year (for example, many listings use ~2.75%), but you should use the exact figure from your Key Information Document / offer.
- Service charges: often apply, especially for flats. They can be material and can change; use the latest schedule from the provider.
Worked examples
Example 1 — £250,000 property, buy 25% share
- Full property value: £250,000
- Share to buy: 25% → share value £62,500
- Deposit: 10% of share → £6,250
- Mortgage amount on share: £56,250
- Mortgage assumption: 5.00% over 25 years → monthly payment ≈ £328.83
- Unowned share: 75% → £187,500
- Rent assumption: 2.75% per year on unowned share → monthly rent ≈ £429.69
- Service charge assumption: £100/month
- Estimated monthly total ≈ £858.52
Example 2 — £240,000 property, buy 40% share
- Share value: £96,000; deposit 10% → £9,600; mortgage £86,400
- Mortgage assumption: 5.00% over 25 years → monthly payment ≈ £505.09
- Unowned share: £144,000; rent at 2.75% → monthly rent ≈ £330.00
- Service charge: £120/month
- Estimated monthly total ≈ £955.09
Example 3 — £240,000 property, buy 50% share
- Share value: £120,000; deposit 10% → £12,000; mortgage £108,000
- Mortgage assumption: 5.00% over 25 years → monthly payment ≈ £631.36
- Unowned share: £120,000; rent at 2.75% → monthly rent ≈ £275.00
- Service charge: £120/month
- Estimated monthly total ≈ £1,026.36
Rent rates and service charges vary by provider and property. Use the calculator inputs to match your offer documents.
Edge cases and exclusions
- Rent reviews: shared ownership rent can be reviewed and increased (provider rules vary).
- Staircasing: buying more shares reduces rent and changes mortgage borrowing (not modelled as a timeline here).
- Eligibility: income limits and criteria are not checked by this calculator.
- Fees: valuation/legal fees and staircasing fees are not included.
- Service charges: can change and can be material; always request the latest schedule from the provider.
Assumptions
- This is a simplified estimate for guidance only.
- Mortgage payments are estimated using a standard repayment mortgage model on the share you buy (after deposit).
- Rent is estimated on the remaining share using the rent rate you enter.
- Service charge is added as a simple monthly amount.
- It does not include fees, stamp duty, insurance, repairs, or future rent/service charge changes.
Methodology
Share value = property value × share percentage.
Deposit = deposit percentage × share value.
Mortgage amount = share value − deposit.
Monthly rent = (remaining share value × rent rate) ÷ 12.
Total monthly cost = monthly mortgage + monthly rent + service charge.
What to do next
- Check affordability to sense-check borrowing capacity.
- Estimate repayments for the mortgage portion of your share.
- Read: Shared ownership monthly costs explained.
- Read: Staircasing explained.
- Glossary: staircasing, service charge, leasehold.
- GOV.UK: Shared ownership scheme (official overview).
FAQ
How does this shared ownership calculator work out the “share value”?
It multiplies the full property value by the share percentage you plan to buy. That share value is the portion you are purchasing.
Is the deposit percentage applied to the full property value or just the share I am buying?
In this calculator, the deposit percentage is applied to the share you are buying. That matches how shared ownership deposits are often described.
What does the shared ownership calculator assume about the mortgage type?
It uses a repayment mortgage estimate for the share you buy, based on the mortgage rate and term you enter. It is not a lender quote.
How is the rent payment calculated on the shared ownership page?
Rent is estimated from the remaining share value (the part you do not own) and the annual rent rate you enter, then converted to a monthly figure.
What is included in “total monthly cost” for shared ownership?
It is the sum of estimated monthly mortgage payment on your share, plus monthly rent on the remaining share, plus any service charge you enter.
Why can service charges make the total monthly cost look high in shared ownership scenarios?
Service charges can be material and they are paid on top of mortgage and rent. They vary by development and can change, so treat the input as a planning assumption.
Does this shared ownership calculator include staircasing costs and future rent increases?
No. It is a snapshot estimate based on your current share, rates and service charge. Staircasing and rent reviews depend on scheme terms and timing.
If I change the share percentage, why do both mortgage and rent figures move?
A higher share means you buy more of the property, so the mortgage part typically rises, while the remaining share falls so rent can decrease.
Can I use this shared ownership calculator to compare two developments with different rent rates?
Yes. Change the rent rate and service charge inputs to reflect each development and compare the total monthly cost outputs.
Is the rent rate the same as an interest rate on a loan?
No. The rent rate is applied to the value of the share you do not own. It is a way to estimate rent, not loan interest.
Why does the shared ownership calculator ask for a mortgage term and rate?
Those inputs are used to estimate the mortgage payment for the share you buy. They let you explore how different mortgage deals change the monthly cost.
What limitations should I keep in mind when using this shared ownership tool?
It does not include eligibility checks, lender criteria, fees, or scheme-specific rules. Use it for budgeting and comparison, then confirm details with the provider and a mortgage adviser.
Can the shared ownership page be used if I already own a share and I am staircasing?
It can help you model a new share percentage as a rough comparison, but it does not calculate staircasing premiums, valuation fees, or legal costs.
How can I share my shared ownership scenario with someone else?
Use the share link to keep your inputs in the URL. It is useful for discussion, but avoid entering personal data into the fields.
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