Upsizing your home

An upsizing mortgage is the loan you take out when you move from your current property to a larger or more expensive one. Unlike a first-time buyer mortgage, you are already on the property ladder, which means you can use the equity in your existing home as a deposit on the new one.

The process works like this: you sell your current home, pay off any outstanding mortgage balance, and use the remaining equity alongside any savings as a deposit. You then take out a new mortgage to cover the rest of the purchase price. Because you are typically putting down a larger deposit than a first-time buyer, you often qualify for lower interest rates and better loan-to-value (LTV) bands.

Most people upsize because their circumstances have changed. A growing family, a need for a home office, or simply wanting more space are all common reasons. Whatever your motivation, the key financial question is whether your income supports the higher monthly payments. Lenders will run a full affordability assessment that looks at your income, outgoings and any existing debts before approving your application.

How much you can borrow depends on three main factors: your household income, your existing equity and the lender's affordability criteria. Most high street lenders offer 4 to 4.5 times your combined annual income. So a household earning £70,000 could borrow between £280,000 and £315,000. Some specialist lenders go up to 5.5 times income for borrowers in certain professions or with higher earnings.

Your equity plays a major role too. If you have built up significant equity in your current home, you can use that as a larger deposit, which reduces your LTV ratio and unlocks better rates. For example, putting down a 25% deposit instead of 10% could save you thousands in interest over the mortgage term. You can use a moving home calculator to estimate the numbers for your situation.

Lenders also stress-test your finances by checking you could still afford payments if interest rates rose by several percentage points. They review your regular outgoings, childcare costs, credit commitments and living expenses. If you have any outstanding debts, paying these down before applying can improve how much you are offered. Getting a competitive mortgage rate makes a significant difference to your monthly costs and total borrowing capacity.

Upsizing comes with several costs beyond the mortgage itself. Understanding these upfront helps you budget properly and avoid surprises during the process.

Stamp duty is often the biggest additional cost. In England and Northern Ireland, you pay nothing on the first £250,000 of the purchase price, then 5% on the portion between £250,001 and £925,000. On a £400,000 property, that works out to £7,500. Wales and Scotland have their own rates. Read more about stamp duty when moving home for the latest thresholds.

Valuation and survey fees vary depending on the type of survey you choose. A basic mortgage valuation costs £250 to £500, while a full building survey on a larger property can run from £600 to £1,500. Solicitor fees for the sale and purchase typically total £2,000 to £4,000. Estate agent fees on your current property sale are usually 1% to 1.5% of the sale price plus VAT. Finally, removal costs range from £500 to £2,000 depending on how far you are moving and how much you need to transport.

When you upsize, you have two main options for handling your existing mortgage: porting it to the new property or taking out a completely new deal. Each approach has trade-offs, and the right choice depends on your current rate, how far through your deal you are and how much extra borrowing you need.

Porting means transferring your existing mortgage deal to the new property. This keeps your current interest rate and avoids early repayment charges (ERCs), which can be 1% to 5% of the outstanding balance. However, you will almost certainly need to borrow more to cover the higher purchase price. This additional borrowing comes as a separate "top-up" product, often at a different rate. Your lender will also reassess your affordability, so porting is not guaranteed. Learn more about porting your mortgage and when it makes sense.

Remortgaging means paying off your old mortgage entirely and starting fresh with a new lender. This gives you access to the whole market and potentially a better overall rate, especially if your equity position has improved. The downside is you may face ERCs on your current deal. If you are within the last few months of a fixed-rate period, it can make sense to wait or negotiate. A mortgage advisor can calculate both scenarios and show you which option saves more over the full term. Compare the best mortgage lenders to see what is available.

Getting approved for an upsizing mortgage follows a similar process to any mortgage application, but there are specific steps that can improve your chances of a smooth approval.

Check your credit report before you apply. Errors on your file can delay or derail applications. Make sure all addresses are correct, close any unused credit accounts and settle any small outstanding balances. Reduce your debt-to-income ratio by paying down credit cards and loans. Lenders look at your total commitments, so lowering these frees up borrowing capacity.

Get a mortgage agreement in principle (AIP) early in the process. This gives you a clear budget and shows estate agents and sellers that you are a serious buyer. An AIP is usually valid for 60 to 90 days and involves a soft credit check that does not affect your score. Gather your documents before applying: three months of bank statements, three months of payslips, your latest P60 and proof of your deposit including your equity statement.

Finally, consider getting matched with a mortgage advisor who specialises in moving home mortgages. They can identify which lenders are most likely to approve your application based on your specific circumstances, saving you time and protecting your credit file from unnecessary hard searches.