Assumptions
How these mortgage calculators are currently modelled
These pages are designed for planning and scenario testing. The assumptions are intentionally visible so you can sense-check the output instead of trusting a black box.
Affordability rules
- Cautious borrowing multiple: 4x income.
- Standard borrowing multiple: 4.5x income.
- Committed monthly costs reduce borrowing through a weighted annual adjustment.
- Stress-rate scenarios are shown at 5%, 6%, 7%.
Property cost defaults
- Solicitor estimate: £1,800.
- Survey estimate: £650.
- Moving estimate: £900.
- Annual maintenance allowance: 1.0% of the property price.
- Selling cost allowance: 1.5% of future sale price.