A mortgage offer is the moment your buying journey becomes real. The lender has checked your income, the property, and your paperwork and decided they’re happy to lend.
But an offer isn’t the end of the process. It comes with an expiry date, and a few things can still go off track if the purchase drags on.
Here’s what you need to know.
How Long a Mortgage Offer Lasts
Most mortgage offers are valid for 3–6 months.
The exact length varies by lender, but the offer letter will state the expiry date clearly.
If your purchase is straightforward, this window is usually enough. But if there are delays in the chain, with surveys or legal work, you might find yourself cutting it close.
Some lenders will extend an offer if the delay isn’t your fault. Others will require updated documents before confirming an extension.
What Can Cause Delays?
1. Survey issues
If your surveyor finds structural problems, damp, or anything that could affect the property’s value, the lender may pause and reassess.
In some cases, they’ll reduce the loan amount or ask for repairs to be completed first.
Quick tip: If you’re unsure what a surveyor actually checks, our surveyor guide breaks it down in plain English.
2. Solicitor or conveyancing delays
Searches can take time. Missing documents can take even longer.
A slow solicitor on either side of the chain can drag things out far beyond what buyers expect.
If you’re staring at a pile of paperwork and feeling unsure, remember: conveyancers manage this every day. The key is staying in the loop.
3. Chain complications
If someone above you hasn’t sold yet, or a seller pulls out, the whole chain stalls.
This is one of the most common reasons buyers hit their offer expiry date.
4. Changes to your own circumstances
Lenders have the right to revisit your affordability if something material changes before completion, for example:
- A new job
- Reduced income
- New loans or credit
- Changes in personal circumstances (e.g., maternity leave)
They may ask for updated payslips, bank statements, or explanations.This can slow things down.
What Happens If Rates Change During Your Offer
Your mortgage rate is secured when the offer is issued.
That means:
- If rates rise, you keep your lower rate.
- If rates fall, you may be able to switch, but only if your lender allows it.
Some lenders let you “re-rate” to a cheaper product. Others treat it as a full new application.
If changing the deal risks delaying the purchase, think carefully before restarting the process.
This is where a mortgage adviser can be useful. They’ll tell you whether switching is worth the disruption.
Can You Renegotiate the Offer?
You usually can’t renegotiate the offer unless something has changed, either with your circumstances or the property itself.
You can renegotiate the purchase price if the survey uncovered issues or the chain has weakened your position.
If the price changes, the lender may need to reassess the loan amount, but your original rate and offer conditions will often remain.
What Happens If the Offer Expires
If you don’t complete in time, you may need to:
- Re-submit documents
- Provide updated bank statements or payslips
- Pass affordability checks again
- Get a refreshed valuation
If rates have risen since your original offer, this can result in a more expensive mortgage.
This is why staying on top of timelines matters, and why good communication between your adviser, solicitor, and the seller’s team makes a real difference.
Final Thoughts
Waiting between a mortgage offer and completion is one of the most stressful stages of buying a home.
Most delays aren’t your fault, they’re simply a normal part of the legal process. If things slow down, don’t assume the worst. Keep everyone updated, respond quickly to requests, and flag concerns early.
If you’re unsure how your lender handles expiry dates or extensions, a mortgage adviser can help you make sense of it.