Answers · UK 2025/26
What is a Mortgage in Principle and do I need one?
A Mortgage in Principle (also called an Agreement in Principle or Decision in Principle) is a lender's initial estimate of how much they might lend you, based on a quick check of your income and credit file, before you have found a property. Most estate agents expect one before accepting an offer.
Full answer
A Mortgage in Principle is a preliminary indication from a lender of roughly how much they would be willing to lend you, based on the information you provide about your income, outgoings and circumstances, along with a soft or sometimes hard credit check, but crucially without yet having a specific property to assess or full documentary proof of income verified. It typically takes anywhere from a few minutes online to a same-day process over the phone or in a branch, and results in a certificate or reference number valid for a limited period, often 60 to 90 days, which you can show to an estate agent when making an offer on a property. Most UK estate agents will not treat an offer as fully credible, and in a competitive market may not even pass it on to the seller, without a Mortgage in Principle in place, since it demonstrates the buyer has at least been assessed as broadly able to borrow the amount needed. It is important to understand that a Mortgage in Principle is not a guaranteed mortgage offer -- the actual formal mortgage application, made once you have found a specific property, involves full verification of income (payslips, bank statements, tax returns for the self-employed), a proper valuation of the specific property, and a full underwriting assessment, any of which could result in a different amount being offered, a decline, or additional conditions, even if the Mortgage in Principle indicated a higher figure. Getting a Mortgage in Principle from more than one lender before house-hunting seriously can also help identify which lenders are likely to offer the best terms for your specific circumstances.
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This answer is informational only and does not constitute financial, tax or legal advice. Figures are for the 2025/26 UK tax year. See our methodology and sources.