If you’re starting to look at properties seriously — especially as a first-time buyer — you’ll hear the phrase “mortgage in principle” (or “offer in principle”) fairly quickly. Here’s exactly what it means, how to get one, and why it matters.
The short version
A mortgage in principle — also called an offer in principle (OIP), agreement in principle (AIP), or decision in principle (DIP); they all mean the same thing — is a written statement from a lender saying they’d be willing to lend you a certain amount, based on a quick look at your finances. It’s not a mortgage offer, and it’s not a guarantee. But it’s a strong signal that you’re a credible buyer.
Why do you need one?
Most sellers and estate agents will ask if you have one before taking your offer seriously. If two buyers offer the same price and one has a mortgage in principle and the other doesn’t, the seller will almost always go with the one who does — it reduces the risk of the sale falling through because the buyer can’t actually get a mortgage.
It helps you, too. It forces you to think realistically about your budget — and about how much it costs to buy — before you fall for a property you can’t afford.
How much can you borrow with one?
A mortgage in principle gives you a ballpark borrowing figure, usually based on around 4 to 4.5 times your income, adjusted for your outgoings, debts, and deposit. It’s an estimate, not a promise — the final figure can change when you make a full application and the lender checks everything in detail. Treat it as the top of your range, not a target.
How do you get one?
You can get one directly from a lender (bank or building society) or through a mortgage broker. It usually takes 15–30 minutes and involves a soft credit check — which doesn’t affect your credit score. You’ll need basic details: your income, employment status, any debts, and the deposit you’re planning to put down.
Does it affect your credit score?
Almost always, no. Reputable lenders and brokers use a soft credit check for a mortgage in principle, which is visible only to you and leaves no mark on your file. Avoid any provider that runs a hard check at this stage, and don’t apply for lots of them in a short space of time.
How long does it last?
Most are valid for 60–90 days. If you haven’t found a property in that time, you can usually renew it. If your circumstances change — a new job, new debt, or a change in income — you may need to reapply.
Mortgage in principle vs a full mortgage offer
A mortgage in principle is the quick, early-stage check. A full mortgage offer comes later: once your offer on a property is accepted, you complete a full application, the lender runs a hard credit check and a valuation of the property, and only then do they issue a binding offer. A mortgage in principle can still be declined at full application if something has changed — so treat it as a green light to start, not the finish line.
It also doesn’t tie you to that lender: you can get a mortgage in principle from one and take your actual mortgage from another.
The bottom line
A mortgage in principle is one of the cheapest, fastest things you can do to make yourself a serious buyer. Get one before you start viewing in earnest — it sharpens your budget and tells sellers you mean business.
Common questions
What is a mortgage in principle?
A mortgage in principle (also called an agreement in principle, decision in principle, or offer in principle) is a written statement from a lender saying they would be willing to lend you a certain amount based on a quick look at your finances. It is not a mortgage offer and not a guarantee, but a strong signal that you are a credible buyer.
How long does a mortgage in principle last?
Most mortgage in principle decisions are valid for 60 to 90 days. If you have not found a property in that time, you can usually renew it.
Does getting a mortgage in principle affect your credit score?
Getting a mortgage in principle usually involves a soft credit check, which does not affect your credit score.
Is a mortgage in principle the same as a mortgage offer?
No. A mortgage in principle is a quick early-stage estimate based on a soft credit check. A full mortgage offer comes later, after your offer on a property is accepted, a full application, a hard credit check, and a valuation. The mortgage in principle can still be declined at that stage if something has changed.
When you make an offer through Woosh, you'll be asked to confirm your OIP status. It keeps the process honest — sellers know who the serious buyers are, and you know you're competing on a level playing field.
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