Mortgage application checklist

Last reviewed: 27 July 2026

A mortgage application runs in five stages: preparation (credit report, budget, documents), an agreement in principle, the full application with underwriting and valuation, the mortgage offer with conveyancing and exchange, then completion. The golden rules are to prepare documents early, answer underwriter queries fast, and avoid new credit or job changes until the keys are in your hand.

Stage 1: before an agreement in principle

Check your credit report with all three agencies (Experian, Equifax, TransUnion) and fix errors.
Register on the electoral roll at your current address.
Work out your true budget: deposit, the monthly payment you are comfortable with, and buying costs (the costs budget sheet covers every line).
Gather your documents early: see the documents checklist.
Close or reduce unused credit where sensible; avoid new credit from here on.
Decide whether to use a broker or go direct. A whole-of-market broker sees more than any one lender.

Stage 2: agreement in principle (AIP)

Get an agreement in principle: a lender's indication of what they might lend you.
Check whether it uses a soft or hard credit search (soft is common; ask first).
Use the AIP amount to set a realistic property search range.
Remember an AIP is not a guarantee: full checks come later.

Stage 3: full application

Offer accepted on a property; instruct a solicitor or conveyancer.
Choose the actual product (rate, term, fees) with your broker or lender.
Submit the full application with all documents.
The lender runs full underwriting and a hard credit check, and values the property.
Consider your own survey on top of the lender's valuation: the valuation is for them, not you.
Answer underwriter queries fast. Speed here saves weeks.
Do not change jobs, take new credit, or move money around unexplained mid-application.

Stage 4: mortgage offer to exchange

Offer issued (typically valid 3 to 6 months, lender-dependent). Check every detail: names, property, rate, term, fees.
Solicitor completes searches and raises enquiries.
Arrange buildings insurance to start from exchange of contracts.
Review the contract, agree a completion date, exchange contracts and pay the deposit. You are now legally committed.
Worried the offer could be pulled? See will my mortgage offer be withdrawn.

Stage 5: completion and after

The solicitor draws down the mortgage funds and completes. Collect the keys.
The solicitor deals with stamp duty (SDLT in England and NI; LBTT in Scotland; LTT in Wales) and Land Registry registration.
Set up the direct debit and note the first (often larger) payment date.
Keep the offer and completion statement somewhere safe.
Diary your deal end date now, minus 6 months: the remortgage switching checklist takes over from there.
Moving in? The moving house checklist handles the practical side.

This page is information, not advice. A regulated mortgage broker manages the application itself and advises on your case: that is who we introduce you to.

Common questions

What should I do before applying for a mortgage?

Check your credit report with all three agencies and fix errors, register on the electoral roll, gather your documents, work out your real budget including buying costs, and avoid taking on new credit. That preparation is most of what separates smooth applications from slow ones.

What should I avoid doing during a mortgage application?

Do not change jobs, take out new credit, miss any payment, or move money around without a paper trail. Underwriters re-check close to completion, and a new loan or unexplained deposit at the wrong moment can delay or unwind an offer.

How long is a mortgage offer valid?

Typically 3 to 6 months depending on the lender, sometimes with extensions for new-build purchases. If your purchase is moving slowly, tell your broker early so the offer can be extended or re-issued rather than expiring mid-conveyancing.

Adam Parker

Founder, MortgageExplained

Adam spent nearly a decade as a mortgage adviser at Just Mortgages, with further experience in commercial finance. He is CeMAP and CF qualified. He built MortgageExplained to do one thing well: explain mortgages in plain English, then introduce you to a regulated broker when you are ready. Every page is written and reviewed by Adam.