Watch out for high rental assessments

Part of the lending criteria for a buy-to-let mortgage includes a monthly rental income bench mark.

This level varies greatly between lenders and can significantly affect the loan size.

For example, some lenders' calculations are based on achieving a rental income level of at least 125% of the mortgage repayment, based on the mortgage deal rate - say hypothetically a discount rate at 4.5%.

Others, though, might offer a discount rate at, say, 3.7% but base the rental assessment on 130% of their standard variable rate at 5.6%.

It's always worthwhile investigating closely the criteria, as some lower rate deals might not meet your lending requirements.