Mortgage decision in principle (DIP) FAQs

A mortgage decision in principle—often shortened to DIP and sometimes called AIP or MIP—is designed to give home buyers an early indication of how much they may be able to borrow.

Because it’s based on information provided at an early stage, it’s normal to have questions about how dependable it is, what it means for your credit file, and what happens after you receive it.

What is a mortgage decision in principle?

A mortgage decision in principle is an initial indication from a lender (or arranged through a broker) of the borrowing range you could be considered for.

It’s typically based on the details you provide up front, such as:

• income
• regular outgoings
• deposit (and sometimes the source of funds)
• basic personal and property information

A DIP is not the same as a formal mortgage offer.

How reliable is a DIP?

A DIP is usually a useful starting point, but it’s best treated as provisional.

When you move from DIP to a full mortgage application, the lender will typically carry out further checks, which can include:

• a more detailed affordability assessment
• verification of income and commitments
• a property valuation
• additional underwriting checks based on the final application details

Because those later steps can assess things differently, the final mortgage outcome may be different from the DIP.

Can my mortgage be declined after a DIP?

Yes. A DIP does not guarantee that you will receive a mortgage offer.

Even if your DIP looks positive, a lender may decline the full application if, for example:

• your circumstances change between DIP and full application
• the property valuation comes in lower than expected
• further underwriting identifies an issue not clear at DIP stage
• the documents provided at full application don’t support the earlier figures

Does a DIP affect my credit score?

In many cases, a DIP is assessed using a soft credit check, which is designed not to impact your credit score.

However, credit-check processes can vary depending on how the decision is arranged and which lender is involved. In some situations, a hard search may be recorded.

If you’re planning to apply for other credit products soon, it’s worth being mindful that credit searches can differ.

How long does a DIP last?

A DIP is normally valid for a limited period.

The exact length depends on the lender and the process used, but it’s commonly issued for a set number of days. If it expires before you complete the next steps—or if your circumstances or the property details change—you may need to request an updated decision.

What’s the difference between DIP, AIP and MIP?

In practice, DIP, AIP and MIP are often used interchangeably.

Different lenders and brokers may prefer different terminology, but they generally refer to the same concept: an early indication of how much you might be able to borrow.

Is an agreement in principle a guarantee?

No. A DIP/AIP/MIP is not a guarantee.

It can help you understand your likely borrowing capacity, but the lender still needs to complete the full underwriting process and assess the property through the formal stages.

Do I need a DIP to make an offer?

It’s not always a strict legal requirement, but it’s often expected by estate agents and sellers.

Having a DIP can make it easier to progress discussions because it shows you’ve taken steps to understand your mortgage position.

When should I get a DIP?

Many home buyers choose to get a DIP early in their search—particularly if you:

• want to understand your likely budget before booking viewings
• are aiming to move quickly once you find the right property
• want to reduce uncertainty when making an offer

Getting a DIP at the right time can help align your planning with the steps needed for a full mortgage application.

Can I get more than one DIP?

Yes. You can request decisions from different lenders.

This can help you compare how different lenders assess your information. If credit checks are involved, it’s worth considering timing and how multiple requests may be recorded.

What happens after I get a DIP?

Once you find a property and your offer is accepted, the next step is usually the formal mortgage application.

At that stage, you’ll typically be asked for more detailed information and documentation. The lender will then carry out further affordability checks and a property valuation before issuing a formal mortgage offer.

Why might my DIP amount be different from what I expected?

A DIP is based on the information available at the time and the lender’s criteria.

Differences can happen due to:

• how a lender assesses income and outgoings
• variations in lender criteria
• changes between DIP stage and later checks
• underwriting outcomes or the result of the property valuation

Can a DIP be used for a remortgage?

The same general principle applies when you’re looking to remortgage or switch, although terminology and process can vary.

An early indication can still be useful for understanding what borrowing might be available before moving into a full application.

Key takeaways

• A DIP/AIP/MIP is an early indication, not a mortgage offer.
• It’s helpful for planning, but it’s provisional.
• A DIP can be declined after further checks.
• Credit-check processes can vary; soft checks are common, but not guaranteed.
• DIPs typically last for a limited period and may need updating.