How Long Does a Mortgage Offer Last? (UK Guide, 2026)
Once a lender issues your mortgage offer, the clock starts running. Most offers are only valid for a set window, and if your completion date slips past it, you can be left scrambling to sort things out at the worst possible moment.
This guide covers how long a mortgage offer typically lasts, what happens if it expires before you complete, and the realistic options if your move or chain is running late.
A mortgage offer isn't the same as a mortgage in principle
It's easy to mix these up.
A mortgage in principle (or agreement in principle) is an early, informal indication of how much a lender might lend you, based on basic details. It's useful for house-hunting and showing an agent you're serious, but isn't a formal commitment. Our guide to getting a mortgage in principle covers that stage.
A full mortgage offer is different: issued after detailed underwriting and a property valuation, it's a formal written commitment to lend a specific amount, on specific terms, for that property. That's the document with the expiry date to watch.
How long does a mortgage offer usually last?
There's no single legal rule here — each lender sets its own validity period, and it can depend on the type of lender and sometimes the type of property.
| Lender type | Typical offer validity | Extensions |
|---|---|---|
| High street banks | Around 6 months | Often a further extension of a few months, subject to fresh checks |
| Building societies | Around 3–6 months | Usually considered case by case |
| Online lenders | Around 3–6 months | Sometimes limited |
| Specialist lenders | Around 3–4 months | Often available, usually with updated income and credit checks |
| New-build-specific offers | Often 9 months or more, depending on the lender | Built in for longer build timelines, rather than a formal "extension" |
These are general patterns reported as of October 2026, not guarantees. Validity periods, extension policies and fees are all set by the individual lender and do change, so always check the figure printed on your own offer letter rather than relying on a typical range.
Build your free moving plan and it'll flag when your mortgage offer is likely to need checking against your target completion date — start your plan here.
What happens if your offer is about to expire
Most offers run out quietly in the background — until a delay somewhere in the chain pushes your completion date past it.
Common causes include a slow local authority search, a chain issue further up the line, a survey that throws up something to negotiate, or a valuation query. None of these are unusual — but they all eat into the time your offer has left.
The moment completion looks likely to slip past your offer's expiry date, tell your lender or broker — an early heads-up gets a better response than a problem that only surfaces in the final week.
Can you extend a mortgage offer?
Often, yes, but it isn't automatic or guaranteed. Most lenders will consider an extension for a genuine reason — legal delays, a chain holding things up, or a slow survey. Some grant a straightforward extension of a few weeks to a few months; others reassess your application against current lending criteria, which can mean updated payslips, bank statements, or a fresh credit check.
As a rough guide, extension fees reported in 2026 tend to sit somewhere in the £100–£300 range, though some lenders waive this if the delay wasn't caused by you. Ask specifically whether your original rate is protected during the extension, or whether you'd move to whatever rate is current when it's granted — this varies by lender and product.
Raise an extension request two to four weeks before your offer is due to expire, rather than in the final days. That gives the lender time to process it, and gives you time to explore other options if it's refused.
If the lender won't extend
It's not the end of the road. The usual options are:
- Reapply with the same lender. Restarts underwriting and may mean new fees, but keeps things with a lender who already knows your case.
- Switch to a different lender. Worth considering if rates or criteria have moved, though this usually means a new valuation and fees.
- Renegotiate your completion date. Ask your solicitor whether the seller's side can move the date, buying time without touching the mortgage.
- Bridging finance, as a short-term last resort. Typically more expensive than a standard mortgage, meant to cover a short gap rather than as a backup plan.
Which option makes sense depends on your situation, and a mortgage broker or financial adviser can assess that for your individual circumstances far better than a generic guide can.
Common mistakes that cause problems
A few patterns come up again and again:
- Treating a mortgage in principle as if it carried the same validity rules as a formal offer.
- Not flagging a likely delay to the lender until the offer has already expired.
- Leaving an extension request until the final few days.
- Assuming a new or extended offer keeps your original rate automatically — check this explicitly.
- Not budgeting for a fresh valuation or application fee if you need to reapply.
Knowing roughly where you are against your offer's expiry date — and checking it regularly as your conveyancing progresses — is the simplest way to avoid being caught out.
The bottom line
A mortgage offer usually lasts three to six months, occasionally longer for new-build purchases, but the exact figure is set by your lender and printed on your offer letter. If completion looks like it might run late, contact your lender early: many will extend for a genuine reason, but it's never guaranteed and can mean fees or a fresh credit check. If an extension isn't possible, reapplying, switching lender, renegotiating the completion date or, as a last resort, bridging finance are the realistic paths. These figures change over time, so check the specifics with your own lender.
This guide is general information, not financial advice.
Once you've had your offer accepted, build your free moving plan. It lines up your mortgage, survey, insurance and every other task to your actual move date, so nothing — including an offer deadline — catches you out. Build your free plan.