Buy-to-Let Mortgage Calculator
Updated on 22 Oct 2026 · Checked by Aotob
On £1,250 a month of rent you could borrow about £187,500.
The 75% loan to value is the limit; you need £62,500 down.
You could borrow
£187,500
Lenders test rent at 125% of the interest at a stressed rate. Higher-rate taxpayers buying personally are usually tested at 145%.
Show the working
Rent test: 15,000 ÷ (125% × 5.5%) = 218,182
LTV: 250,000 × 75% = 187,500
Lower = 187,500
Borrowing by rent
| Rent a month | At 125% | At 145% |
|---|---|---|
| 1,000 | 174,545 | 150,470 |
| 1,125 | 187,500 | 169,279 |
| 1,250 | 187,500 | 187,500 |
| 1,375 | 187,500 | 187,500 |
| 1,500 | 187,500 | 187,500 |
Questions people ask
How do lenders work out a buy-to-let loan?
The rent must cover the interest at a stressed rate by a set ratio (ICR): usually 125% for basic-rate taxpayers and limited companies, 145% for higher-rate taxpayers.
How much deposit do I need?
Usually 25%, sometimes 20% or 40% for better rates.
Is there extra stamp duty?
Yes, a 5% surcharge on every band for additional homes in England and Northern Ireland from October 2024.
Updated 22 Oct 2026Source: Standard loan maths, checked October 2026Checked by AotobTypical lender rules; each lender differs.Report an issue