You usually do not need documents for a basic mortgage calculator, as you can enter estimated figures such as your income, deposit, debts, mortgage term and interest rate. For an agreement in principle or full application, a lender may ask for identification, proof of address, recent payslips, P60s, bank statements and evidence of your deposit. If you are self-employed, you may also need tax calculations, tax year overviews and business accounts. Requirements vary, so check with an FCA-authorised lender or mortgage broker before applying and provide accurate figures.