UK Help to Buy vs. Shared Ownership Scheme Calculator
Estimate and compare core costs for Help to Buy (equity loan) and Shared Ownership scenarios in the UK. This tool provides a simple, transparent summary and signposts official guidance; use it as an initial comparison, not formal financial advice.
- Page updated:
- Jun 10, 2026
- Tool version:
- v1.1.0
Overview
Estimate the monthly cost of a UK Shared Ownership home: the mortgage on the share you buy, the rent on the share you don't own, and the service charge. Shared Ownership lets you buy a portion of a property (typically 10%–75%) and pay subsidised rent on the rest.
Educational estimate, not financial advice. Note: the Help to Buy equity loan scheme closed to new applicants in March 2023, so this tool focuses on the current Shared Ownership scheme. Check mortgage and rent terms with your provider.
Results
Value of the share you buy
$120,000.00
Mortgage amount on your share
$114,000.00
Mortgage payment on your share
$666.43
Rent on the unowned share
$412.50
Total estimated monthly cost
$1,178.93
How to read the result
- What it means
- The displayed value is an estimate based on your inputs. It represents the calculated scenario under current assumptions, not a guaranteed amount.
- Next step
- Use the result as a starting point. Adjust parameters to compare scenarios and validate with a professional when needed.
- Calculation limits
- The model uses simplified formulas and cannot account for all variables in your specific case (local regulations, personal conditions, temporal changes).
Methodology
Shared Ownership monthly cost has three parts:
- Mortgage on your share: the share value = full property value × share %. Subtract your deposit to get the loan, then apply the standard repayment-mortgage formula: M = L × r(1+r)^n ÷ ((1+r)^n − 1), where L is the loan, r the monthly interest rate (annual rate ÷ 12) and n the number of monthly payments (term × 12). If the rate is 0%, the payment is simply loan ÷ months.
- Rent on the unowned share: the housing provider charges rent on the portion you do not own. Unowned value = full value − share value; monthly rent = unowned value × annual rent rate ÷ 12. The rate is commonly 2.75% and capped at 3% per year under current rules.
- Service charge: a monthly charge for building/estate maintenance, added as entered.
Total monthly cost = mortgage + rent + service charge.
Assumptions and limitations: a repayment (not interest-only) mortgage; rent and service charges typically rise over time (often RPI/CPI-linked) and are not escalated here; excludes buildings insurance, ground rent, stamp duty and the costs of 'staircasing' (buying further shares). Estimates only.
Sources: GOV.UK Shared Ownership and Own Your Home guidance — see citations.
Glossary+−
- Shared Ownership
A scheme to buy a share of a home (typically 10%–75%) with a mortgage, paying rent on the remaining unowned share.
- Staircasing
Buying additional shares in a Shared Ownership home over time, increasing ownership and reducing rent.
- Unowned Share
The portion of the property still owned by the housing provider, on which rent is charged.
- Service Charge
A recurring charge for the upkeep of communal areas, buildings or the estate.
- Help to Buy Equity Loan
A government equity loan scheme for new-build homes, closed to new applicants since 31 March 2023.
Key takeaways
Enter the property value, your share, deposit, mortgage terms, rent rate and service charge to estimate the total monthly cost of a Shared Ownership home.
Estimate only — excludes insurance, stamp duty, fees, staircasing and future rent rises. Confirm terms with your provider and GOV.UK guidance.
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Real Estate & HousingWorked examples
Example: £300,000 home, 40% share, 5% mortgage over 25 years
A buyer purchases a 40% share with a £6,000 deposit and pays 2.75% rent on the rest, plus a £100 service charge.
Interpretation
The estimated monthly outlay is about £1,179: roughly £666 mortgage, £413 rent and £100 service charge. Buying a larger share raises the mortgage but lowers the rent.
Frequently asked questions
How does Shared Ownership work?
You buy a share of a home (typically 10%–75%) with a mortgage and deposit, and pay rent to the housing provider on the share you don't own, plus any service charge. You can buy further shares later ('staircasing').
How much is the rent on the unowned share?
Providers set it as an annual percentage of the unowned share's value — commonly 2.75%, capped at 3% under current rules. It is charged monthly and usually rises each year.
Is Help to Buy still available?
The Help to Buy equity loan scheme closed to new applicants on 31 March 2023. This calculator therefore focuses on the Shared Ownership scheme, which remains open.
What costs are not included?
Buildings insurance, ground rent, stamp duty, mortgage fees and staircasing costs are excluded, and rent/service charges typically increase over time. Treat the result as an initial monthly estimate.
Sources & references
- GOV.UK — Shared Ownership homes: buying, improving and selling: https://www.gov.uk/shared-ownership-scheme
- GOV.UK — Own Your Home (affordable home ownership schemes): https://www.gov.uk/affordable-home-ownership-schemes
- GOV.UK — Help to Buy: equity loan (closed to new applicants): https://www.gov.uk/help-to-buy-equity-loan
Quality & oversight
- Author
- Ugo Candido, MBA
- Maintained by
- Ugo Candido, MBA
- Page updated
- Jun 10, 2026
- Tool version
- v1.1.0