How much you can borrow will depend on both your incomes.
In the past the amount you could borrow under a mortgage was based just on earnings. Recently it has become more common for lenders to make an affordability assessment, looking at your whole financial situation, when calculating how much they will lend you.
It’s important to give your lender as much detail as you can about both your earnings and outgoings so that you’re offered a mortgage you can afford. You also need to remember to budget for the one-off costs of buying a property such as administration and solicitor fees and Stamp Duty.
Unmarried couples are usually treated the same as a husband and wife in working out how much they can borrow.
Use the Money Advice Service mortgage calculator to help you work out how much you can afford to borrow.