Calculators for First-Time Home Buyers
Essential calculators for first-time home buyers: affordability, mortgage, stamp duty, and property insurance.
The Essential Calculator Toolkit for First-Time Buyers UK 2025
Buying your first home in the UK involves more numbers than almost any other financial decision. From working out what you can afford, to calculating stamp duty, to projecting monthly mortgage repayments — getting comfortable with the figures before you start viewing properties will save you time, stress, and potentially thousands of pounds.
The 4.5x Income Rule: Affordability
Most UK lenders will offer up to 4.5 times your annual gross income as a maximum mortgage. Some lenders — particularly for professionals or those with large deposits — will stretch to 5x or even 5.5x, but 4.5x is the standard affordability benchmark used for stress testing. On a joint application, lenders typically use combined income.
First-Time Buyer Affordability Benchmarks
| Annual Income | Max Mortgage (4.5x) | With 10% Deposit | With 20% Deposit |
|---|---|---|---|
| £30,000 | £135,000 | £150,000 property | £168,750 property |
| £45,000 | £202,500 | £225,000 property | £253,125 property |
| £60,000 (joint) | £270,000 | £300,000 property | £337,500 property |
| £80,000 (joint) | £360,000 | £400,000 property | £450,000 property |
First-Time Buyer Stamp Duty Relief
From April 2025, the first-time buyer stamp duty threshold reverts to the standard rates (the temporary relief introduced in 2022 expired). First-time buyers pay 0% on the first £300,000 and 5% on the portion from £300,001 to £500,000. Properties over £500,000 do not qualify for FTB relief and standard rates apply. Always verify current thresholds at gov.uk as these change.
Lifetime ISA (LISA): The 25% Bonus
The Lifetime ISA allows first-time buyers to save up to £4,000 per year and receive a 25% government bonus — up to £1,000 per year. The LISA can be used on properties worth up to £450,000. You must be between 18 and 39 to open one, and funds must have been in the account for at least 12 months before use. Withdrawing for any other purpose incurs a 25% penalty (which takes back more than just the bonus).
Note: The Help to Buy ISA closed to new savers in November 2019, though existing account holders can still claim the bonus until November 2029.
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