The amount you can borrow for a buy-to-let property typically depends on the potential rental income of the property, your personal income, and your credit history. Most lenders require the rental income to be 25-30% higher than your mortgage payments. This is often calculated as 125-130% of the mortgage payments at a 'stress' interest rate, which can be higher than the actual rate you'll pay. The lender will also consider your personal income and financial circumstances. As a general rule, you might be able to borrow around 75-80% of the property's value, but this can vary widely depending on the lender and your individual situation.