You know your mortgage payment. But do you know your total housing cost?
For many UK buyers, the mortgage is only part of the monthly cost. It often makes up just 70-80% of what you pay. Service charges, ground rent, insurance, and repairs add hundreds more each month. If you miss these costs, your budget will fall short.
This calculator shows the full picture. It combines your mortgage payments with other property costs to show your true monthly total.
Beyond the Mortgage Payment
Consider a typical London flat purchase:
Property: £450,000 leasehold flat
- Loan amount (15% deposit): £382,500
- Interest rate: 5.5%
- Loan term: 25 years
- Monthly mortgage (repayment): £2,349
That's your mortgage. Now add ongoing costs:
- Service charge: £250/month
- Ground rent: £50/month
- Buildings insurance: £40/month (if not in service charge)
- Maintenance reserve: £150/month
Total monthly housing cost: £2,839
That's £490 more than the mortgage alone. Over a year, nearly £6,000 extra. This matters when lenders assess your affordability and when you plan your monthly budget.
Repayment vs Interest-Only Mortgages
UK lenders offer two main repayment types:
Repayment Mortgages (Capital and Interest) Each payment pays off some of the loan. When the term ends, you own the home fully. This is the standard choice for most buyers.
Interest-Only Mortgages You only pay interest each month. The loan amount does not go down. Monthly payments are lower, but you still owe the full loan amount at the end. This is mostly used by investors.
The calculator shows both options. Compare them to see the difference in monthly costs.
What to Include in Ongoing Costs
Your maintenance base should cover these recurring expenses:
Service Charges (Leaseholds) Flat owners pay service charges covering building insurance, common area maintenance, lift servicing, and reserve funds. Charges range from £1,500 to £5,000+ annually depending on the building. Always check the last three years of service charge accounts before buying.
Ground Rent Traditional leasehold flats pay ground rent to the freeholder. Modern leases should have peppercorn (zero) ground rent following the Leasehold Reform Act 2022. Older leases may have ground rent up to several hundred pounds annually. Watch for doubling clauses in pre-2022 leases.
Buildings Insurance For houses, budget £300-600 annually. For flats, this is typically included in service charges.
Council Tax Not included in this calculator as it varies by local authority and band. Budget £1,200-3,000+ annually depending on location and property value.
Maintenance Reserve Set aside money for repairs. A common rule: 1% of property value annually. For a £450,000 property, that's £4,500 per year or £375 monthly.
Before buying, always commission a building survey to identify potential maintenance issues.
Leasehold Considerations
Most flats in England and Wales are leasehold. Here are key points that affect your costs:
Lease Length Leases under 80 years cost a lot to extend. A rule called 'marriage value' makes the price jump up. Always check how many years are left on the lease before you buy.
Major Works You may have to pay for big repairs like a new roof. Check if the building has a 'sinking fund' to cover these costs. Ask about any planned work.
Cladding Issues Some buildings need expensive safety work on cladding. This can make insurance hard to get. It can also make it hard to get a mortgage. Check the building's safety status.
Always get legal advice to understand these issues fully.
Using the Calculator
Step 1: Enter property details Start with the purchase price and your deposit percentage. The calculator derives your loan amount.
Step 2: Set mortgage terms Enter the interest rate from your mortgage offer. Set your term (typically 25-35 years). Choose repayment or interest-only.
Step 3: Add ongoing costs Enter a single monthly figure for all non-mortgage costs. Or expand the breakdown to enter service charges, ground rent, and maintenance separately.
Step 4: Review total outgoings See your complete housing cost per month plus annual totals.
Affordability Context
Use your total monthly figure to check affordability:
Lender Affordability Tests Lenders stress-test mortgages at higher rates (typically 3% above the standard variable rate or product rate, whichever is higher). They also cap lending based on income multiples (typically 4-4.5x household income).
Budget Reality Your actual budget needs to cover the mortgage plus all other costs. If total housing costs exceed 35% of net household income, you may struggle when rates rise or income drops.
Compare your results with our rent vs buy calculator if you're deciding whether to purchase.
What's Not Included
This calculator covers recurring property costs. Some expenses sit outside:
One-off Purchase Costs Stamp Duty Land Tax, solicitor fees, survey costs, and moving expenses. Always budget for these additional upfront costs.
Utilities Energy bills, water, broadband, and TV licence are user costs rather than property costs.
Contents Insurance Covers your belongings, not the property itself.
Expert Advice and Rules
Before proceeding with any property purchase, get advice from qualified, regulated experts:
Mortgage Advice
Talk to an FCA-regulated mortgage adviser. Check their credentials at FCA Register.
Legal Services
Use a qualified solicitor or licensed conveyancer. Check registration with SRA or CLC.
Property Surveys
Commission a survey from a RICS-registered surveyor. Find one at RICS Find a Surveyor.
Disclaimer: This calculator provides estimates only. Actual repayments depend on your lender's terms and conditions. Mortgage rates and availability change frequently. Always confirm figures with your lender before making financial decisions. This is general guidance, not financial or legal advice. Consult qualified professionals before making property decisions. Information current as of January 2026.