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Shared Ownership Calculator

Your monthly mortgage, rent and service charge, how it compares with buying outright, and what staircasing would cost.

Checked by the SumAtlas teamUpdated 7 October 2026SourcesHow we check our figuresIndependent: not a government website

Your shared ownership home

The home and your share
More optionsOptional. The defaults suit most people; change these if your situation is different.

Free to use. Your details are not saved to an account.

Your summary

Your monthly cost£1,126
Mortgage£563
Rent£413
Service charge£150

Buying 40% of a £300,000 home costs £120,000. With a £12,000 deposit you pay about £563 mortgage, £413 rent and £150 service charge a month.

£120,000 share price£12,000 deposit£413 rent a month

THE COMPLETE PICTURE

Your results in detail

Mortgage£563On £108,000
Rent£4132.75% of £180,000
Service charge£150
Stamp Duty on your share£0
What we assumed
Where
England
Mortgage
4.75%, 30 years, repayment
Rent
2.75% a year, rising 3%
Prices
Rising 3% a year

Not right for you? Change it under More options.

Where your money goes each month

Mortgage on your share, rent on the rest, plus charges.

Mortgage£563
Rent£413
Service charge£150

Only the mortgage part builds up equity you own. The rent and service charge are like rent in a rented home.

Against buying the whole home

With the same £12,000 deposit.

ItemShared ownershipBuy outright
Mortgage needed£108,000£288,000
Loan to value90%96%
Mortgage a month£563£1,502
Rent a month£413£0
Total a month£1,126£1,652

Buying outright would need a bigger deposit

Your deposit is only 4.0% of the full value. Most lenders need at least 5%: £15,000.

Stamp Duty: two ways to pay

Choose when you buy. You cannot switch later.

ItemPay on your sharePay on full value
Stamp Duty now£0£0
When you staircaseTax may be due above 80%Nothing more

First-time buyer relief applies because the full value is £500,000 or less.

Your rent over the next 10 years
YearRent a monthRent a year
Year 1£413£4,950
Year 2£425£5,099
Year 3£438£5,251
Year 4£451£5,409
Year 5£464£5,571
Year 6£478£5,738
Year 7£493£5,911
Year 8£507£6,088
Year 9£523£6,271
Year 10£538£6,459

Worth knowing

Shared ownership has rules a normal purchase does not.

Repairs

On most newer leases the landlord helps with some essential repairs for the first 10 years. After that, and on older leases, you are usually responsible for all repairs even though you only own part of the home.

Selling

Your housing provider usually has a period to find a buyer before you can sell on the open market. You sell your share at its value at the time.

Rent and service charges rise

Rent usually rises each year in line with inflation, set by your lease. Service charges can rise too, sometimes sharply.

England rules. Your provider's lease sets the rent, rent increases and staircasing terms.

THE SHARED OWNERSHIP GUIDE

Shared ownership, explained

Shared ownership lets you buy part of a home with a smaller deposit and mortgage, and pay rent on the rest. This guide explains who can apply, what it really costs each month, how rent and service charges rise, how to buy more shares, the Stamp Duty choices, and how it compares with buying outright.

1The basics

What shared ownership is

With shared ownership you buy a share of a home, usually between 10% and 75%, and pay rent to a housing provider, usually a housing association, on the share you do not own. You take out a mortgage for your share, so the deposit and loan are much smaller than buying the whole home.

You can buy more shares later, a process called staircasing, often up to 100%. Shared ownership homes are almost always leasehold, so you also pay a service charge and must follow the terms of the lease.

2Eligibility

Who can apply

In England you can usually buy through shared ownership if your household income is:

  • £80,000 a year or less outside London, or
  • £90,000 a year or less in London,

and one of these applies:

  • you are a first-time buyer;
  • you used to own a home but cannot afford to buy one now; or
  • you already own a shared ownership home and want to move.

Providers also check that you can afford the costs and cannot afford to buy a suitable home outright. Some homes give priority to local people, key workers or members of the armed forces.

3Costs

Your monthly costs

Each month you usually pay three things:

  1. Mortgage on the share you buy.
  2. Rent on the share you do not own, often around 2.75% of its value a year for new homes.
  3. Service charge and ground rent for the building, insurance and management.

Only the mortgage builds equity you own. The rent and service charge are housing costs, much like renting. Lenders include all three in their affordability check.

4Worked example

A worked example

A 40% share of a £300,000 flat, with a 10% deposit, a 4.75% mortgage over 30 years and a £150 monthly service charge:

40% of a £300,000 home
  1. Share price40% of £300,000£120,000
  2. Deposit10% of the share£12,000
  3. Mortgage payment£108,000 at 4.75% over 30 years£563.38
  4. Rent2.75% of £180,000, divided by 12£412.50
  5. Service charge£150.00
Monthly cost£1,125.88

The calculator lets you change every one of these, including the rent percentage and service charge in your provider's key information document.

5Your share

Choosing your share

A bigger share means a bigger deposit and mortgage but less rent. Because rent is usually cheaper than mortgage interest plus capital, the total monthly cost rises as your share grows, but so does the part of the home you own.

A £300,000 home at 4.75% over 30 years, 10% deposit, £150 service charge
ShareDepositMortgageRentTotal a month
25%£7,500£352£516£1,018
40%£12,000£563£413£1,126
75%£22,500£1,056£172£1,378

Buy the largest share you can comfortably afford. It reduces rent, which rises every year, and means less to buy when you staircase.

6Comparison

Against buying outright

With the same £12,000 deposit, buying the whole £300,000 home would need a £288,000 mortgage, a 96% loan-to-value that most lenders will not offer. Even if you could, the mortgage would cost about £1,502 a month, plus the same service charge: £1,652 in total.

Shared ownership (40%)
Deposit
£12,000
Mortgage
£108,000
Monthly cost
£1,126
You own
40%
Buy outright
Deposit
£15,000 or more (5%)
Mortgage
Up to £285,000
Monthly cost
About £1,637
You own
100%

Shared ownership is cheaper to get into and often cheaper each month. Buying outright builds equity in the whole home and avoids rent rises and lease restrictions. If you can afford to buy outright, it is usually the better long-term choice.

7Rent

Rent and rent increases

Your rent is set as a percentage of the value of the share you do not own when you buy. It then rises each year by a formula in your lease. Many older leases use RPI inflation plus 0.5%; newer leases are often linked to CPI inflation plus 1%.

Rent of £412.50 a month rising 3% a year
YearRent a monthRent a year
1£412.50£4,950
3£437.62£5,251
5£464.27£5,571
10£538.22£6,459

Rent rises even if prices fall

Rent increases follow inflation, not house prices. Staircasing is the main way to reduce your rent.

8Charges

Service charges and repairs

Most shared ownership homes are flats or houses on managed estates with a service charge for building insurance, cleaning, gardening, lifts and a reserve fund for major works. Service charges can rise significantly and are payable in full whatever share you own.

On newer leases the provider helps with some essential repairs during the first 10 years. Otherwise, and after that period, you are usually responsible for all repairs and maintenance inside your home, even though you own only part of it.

9Buying more

Staircasing

Staircasing means buying more shares. You pay the market value of the share at the time, based on a RICS valuation, plus fees. If prices have risen, the extra share costs more than it would have at the start.

Staircasing from 40% to 75% after 5 years
  1. Value today£300,000
  2. Value after 5 years at 3% a year£347,782
  3. Cost of 35% more£121,724
  4. Rent before£478.20 a month
  5. Rent after£199.25 a month
Rent saved£278.95 a month

Buying the remaining 60% at the same point would cost £208,669 and end the rent entirely. Many newer leases also let you buy 1% at a time for the first 15 years with reduced fees.

  1. 1Tell your provider

    Ask for a staircasing pack and how much you can buy.

  2. 2Get a valuation

    A RICS surveyor values the home. The valuation is usually valid for 3 months.

  3. 3Arrange the money

    Usually by remortgaging or a further advance from your lender.

  4. 4Complete

    Your solicitor completes the purchase and your rent is reduced.

10Tax

Stamp Duty

In England and Northern Ireland you choose how to pay Stamp Duty when you first buy:

Pay on your share
Now
Tax on the share price
Staircasing
Tax may be due once you own more than 80%
Best if
You may not staircase much
Market value election
Now
Tax on the full value
Staircasing
No more Stamp Duty
Best if
The full value is below the tax threshold

First-time buyer relief can apply either way if the full market value is £500,000 or less. For a first-time buyer on a £300,000 home, both options cost £0. For a home mover buying 40% of £450,000, paying on the share costs £1,100, while paying on the full value costs £12,500 but nothing more later.

11Selling

Selling your home

When you sell, your provider usually has the first chance to find a buyer for your share, for a set period. If it cannot, you can sell on the open market. You sell at the current market value, so you benefit from any rise in value on your share, and lose if prices fall.

If you have staircased to 100%, you can usually sell like any other home, though leasehold terms may still apply.

12Borrowing

Mortgages and deposits

Fewer lenders offer shared ownership mortgages, so rates can be slightly higher. Deposits are usually 5% to 10% of the share price, not of the whole home. Some buyers use savings to buy their share outright, with no mortgage.

Lenders check affordability on the mortgage, rent and service charge together. Our affordability calculator gives a first estimate of what you could borrow.

13Weighing it up

Pros and cons

Advantages
Deposit
Much smaller
Mortgage
Smaller and easier to get
Monthly cost
Often below buying outright
Security
Long lease, not a tenancy
Drawbacks
Rent
Rises every year
Repairs
Usually yours in full
Selling
Can be slower
Lease
Restrictions on letting and changes
14Across the UK

Outside England

Scotland, Wales and Northern Ireland run their own schemes. Scotland mainly uses shared equity schemes, where you own the whole home but the government holds a stake and you pay no rent. Wales has its own shared ownership and Homebuy schemes, and Northern Ireland has Co-Ownership. Rules and costs differ, so check the scheme in your nation.

15Budget

Costs when you buy

On top of your deposit, budget for:

  • Legal fees, often a little higher than for a normal purchase because of the lease.
  • Stamp Duty, if any is due on your share or the full value.
  • Mortgage fees, such as an arrangement fee and valuation.
  • A reservation fee to the provider, often a few hundred pounds, usually taken off the price at completion.
  • A survey, if you want one. New-build homes usually come with a warranty instead.

Your provider gives you a key information document before you reserve. It sets out the rent, service charge, rent increase formula, staircasing rules and resale terms. Read it carefully, and ask your solicitor to explain anything unclear.

16Ready reckoner

Staircasing ready reckoner

Starting with 40% of a £300,000 home, if prices rise 3% a year, the home is worth about £347,782 after 5 years. Here is what buying more would cost then, and what it would do to the rent:

Staircasing after 5 years, rent £478.20 a month before
BuyCostYou ownRent after
10% more£34,77850%£398.50
25% more£86,94665%£278.95
35% more£121,72475%£199.25
60% more£208,669100%£0

If prices fall, staircasing gets cheaper. If they rise faster than your savings grow, each share becomes harder to afford, which is one reason many owners never reach 100%.

17Comparison

Against renting

Compared with renting privately, shared ownership usually offers more security, a long lease rather than a tenancy, and a share of any rise in the home's value. Your monthly cost may be similar to or lower than local rents, especially in expensive areas.

But you also take on costs a tenant does not: repairs, a service charge that can rise, and the cost and time of selling. If you may move within a few years, the buying and selling costs can outweigh any gain. Our rent versus buy calculator can help you compare.

18Other schemes

Older buyers and disabled buyers

Older People's Shared Ownership is for people aged 55 or over. It works like standard shared ownership, but you can only buy up to 75%, and once you own 75% you pay no rent on the rest.

Home Ownership for people with Long-term Disabilities (HOLD) helps people with a long-term disability buy a home that meets their needs, if the homes available through standard shared ownership do not.

Both schemes have the same income limits and most of the same rules as standard shared ownership. Ask providers in your area which homes are available.

19Summary

Key numbers

10% to 75%
Typical starting share
2.75%
Common yearly rent on the share you don't own
£80,000
Household income limit (£90,000 in London)
5% to 10%
Deposit, as a share of your share
80%
Stamp Duty may be due when you staircase above this
Questions

Frequently asked

How does shared ownership work?

You buy a share of a home, usually 10% to 75%, with a mortgage, and pay rent to a housing provider on the rest. You can buy more shares later.

How much is the rent?

Often around 2.75% a year of the value of the share you don't own for new homes, rising each year by a formula in your lease.

Who can buy through shared ownership?

Usually households earning £80,000 or less (£90,000 in London) who are first-time buyers, used to own a home, or already own a shared ownership home.

What is staircasing?

Buying more shares in your home, at its market value at the time. Your rent falls as your share rises.

Do I pay Stamp Duty on shared ownership?

You choose: pay on your share now (with more possibly due once you own over 80%), or pay on the full value up front and nothing more later.

Can I rent out my shared ownership home?

Usually not without your provider's permission, which is normally only given in exceptional circumstances.

Can I extend or renovate?

You usually need the provider's permission for major changes, as set out in the lease.

What happens if I fall behind on rent?

Missing rent puts your home at risk, just like missing mortgage payments. Contact your provider early if you are struggling.

Do I get my deposit back when I sell?

You receive the value of your share at the time, less the mortgage still owed, so your deposit is part of your equity.

Is shared ownership worth it?

It can be a good way onto the ladder if you cannot buy outright, especially if you plan to staircase. Compare the full monthly cost, including rising rent and service charges, with renting and with buying outright.

Can I pay off my mortgage early?

Yes, subject to your mortgage terms. Paying off the mortgage does not reduce the rent, which is only reduced by buying more shares.

What if the value of the home falls?

Your share falls in value too. Staircasing becomes cheaper, but if you sell, you receive less than you paid. The rent is not reduced because prices fall.

Good to know

Illustrative, England rules. Your provider's key information document and lease set the actual rent, increases and staircasing terms.