Introduction.
Moving home means managing two transactions at once: selling one property and buying the next, usually on the same day.
The mortgage links them. Your existing deal may carry early repayment charges or be portable; your equity becomes your deposit; and your income, which has probably changed since you last borrowed, decides what you can buy next.
This guide explains how to work out your budget before you list, how to choose between porting and a new mortgage, what stamp duty and moving costs to plan for, and what to do if your chain runs into trouble.
The earlier we talk, the more options you have. Ideally, speak to us before you put your home on the market.
Agree your budget and mortgage in principle before you list your home, so you can move quickly when the right property appears.
01What could you afford?
Your next budget comes from two things: the equity you will release from your sale and what lenders will now lend you.
What has changed since you last borrowed
- Your income. A pay rise, promotion, bonus or a partner returning to work can increase what you can borrow.
- Your equity. Repayments and price growth both add to your deposit.
- Your commitments. Car finance, childcare and loans reduce affordability.
- Lender criteria. Income multiples and stress tests have changed in recent years.
Income Change Calculator
Our free calculator at artilliumfinance.com shows how a change in income alters what you could borrow, from 4 to 6.5 times income.
Borrowing by income
| Joint income | 4.5× | 5.5× |
|---|---|---|
| £80,000 | £360,000 | £440,000 |
| £100,000 | £450,000 | £550,000 |
| £150,000 | £675,000 | £825,000 |
Illustrative. Higher multiples are usually limited to higher earners and stronger applications, and depend on your outgoings.
A mortgage in principle shows estate agents and sellers you are ready to proceed, and makes your offer more credible.
02Port, switch or repay?
If you are part-way through a fixed rate, leaving it early may trigger an early repayment charge. Porting can avoid that, but it is not always the cheapest route.
| Port and top up | New mortgage | |
|---|---|---|
| Existing deal | Moves with you to the new property | Repaid at completion |
| Extra borrowing | On your lender’s current rates, often a separate product | One rate across the whole loan |
| Early repayment charge | Usually avoided | Payable if still in the deal |
| Checks | Full application with your lender | Full application with any lender |
| Choice | One lender | The whole market |
Porting is not automatic
Your lender reassesses affordability and the new property. If either has changed, it can decline to port, so check early.
Comparing the two
| £445,000 loan | Port + top up | New mortgage |
|---|---|---|
| Rate | 3.89% + 4.49% | 4.29% |
| Monthly payment | £2,401 | £2,421 |
| Early repayment charge | £0 | £4,200 |
| Two-year cost | £57,615 | £62,297 |
Ported £210,000 at 3.89% plus a £235,000 top-up at 4.49%, against a new £445,000 loan at 4.29% with a 2% charge on £210,000. 25-year repayment terms. Illustrative rates.
03From equity to deposit.
Your deposit is what is left of your equity once the old mortgage and the costs of selling and buying are paid.
A worked example
| Amount | |
|---|---|
| Sale price of current home | £450,000 |
| Less mortgage balance | −£210,000 |
| Less estate agent, 1.2% + VAT | −£6,480 |
| Less sale legal fees | −£1,500 |
| Less stamp duty on £650,000 | −£22,500 |
| Less purchase legal, survey, removals | −£4,800 |
| Deposit available | £204,720 |
Illustrative costs. Your own figures will differ.
Why the band matters
Lenders price in loan-to-value bands, often at 60%, 75%, 80%, 85% and 90%. Moving just under a threshold can lower your rate across the whole loan.
Adviser’s note
If you are close to a band, a small change in the price you offer or the deposit you put in can be worth more than negotiating the last few thousand pounds.
04Stamp duty and moving costs.
Stamp duty is usually the largest cost of moving. These are the rates in England and Northern Ireland for a home mover replacing their main residence.
| Part of the price | Rate |
|---|---|
| Up to £125,000 | 0% |
| £125,001 to £250,000 | 2% |
| £250,001 to £925,000 | 5% |
| £925,001 to £1.5 million | 10% |
| Above £1.5 million | 12% |
| Purchase price | Stamp duty |
|---|---|
| £450,000 | £12,500 |
| £650,000 | £22,500 |
| £1,000,000 | £43,750 |
| £1,500,000 | £93,750 |
Rates from 1 April 2025. Scotland and Wales have their own taxes. Check current rates before you buy.
Buying before you sell
If you complete on your new home before selling the old one, the 5% higher rate for additional properties applies. You can usually reclaim it if you sell your previous main home within three years.
Other costs to budget for
- Estate agent’s fee on your sale
- Legal fees on both sale and purchase
- Survey: a RICS Level 2 or Level 3 report
- Mortgage product and valuation fees
- Early repayment charge, if any
- Removals, storage and any work on the new home
05Your sale, purchase and chain.
Most moves complete the sale and the purchase on the same day. Getting the order right keeps the chain moving.
Plan your budget
We work out your borrowing and costs and arrange a mortgage in principle.
Before you listSell, or find a buyer
Many sellers wait until they have an offer before making their own, so they are in a stronger position.
ProceedableOffer accepted
We submit the full application and the lender values the new property.
Usually two to four weeksMortgage offer
Most offers last around six months. Your solicitor completes searches and enquiries.
Legal workExchange
Contracts are exchanged on both properties and a completion date is fixed.
Now legally bindingCompletion
The old mortgage is repaid, the new one drawn, and you collect your keys.
Moving dayInsure from exchange
Once you exchange, you are usually responsible for insuring the new home. Buildings cover should start that day.
06If the chain breaks.
A buyer pulling out does not have to mean losing the home you are buying. There are several ways to keep a purchase alive.
| Option | When it can help |
|---|---|
| Find a new buyer quickly | Often the simplest answer if your seller can wait. |
| Bridging finance | A short-term loan secured on your current home, repaid when it sells. Quick but more expensive than a mortgage. |
| Let to buy | Remortgage your current home to a buy-to-let and use the equity released towards your purchase. |
| Borrow on income alone | If you can afford both mortgages, some lenders will lend before you sell. |
Bridging loans
Bridging interest is charged monthly and fees can be significant. You need a clear exit, usually the sale of your current home. Your home may be repossessed if you do not keep up repayments on a mortgage or any other debt secured on it.
Reducing the risk
- Choose a buyer who is chain-free or has a mortgage in principle
- Instruct your solicitor early and answer enquiries quickly
- Keep your mortgage offer valid: tell us at once if anything changes
07Protecting your new home.
A larger mortgage and a bigger home usually mean your existing cover no longer fits.
| Cover | Why review it now |
|---|---|
| Life insurance | The amount and term should match your new mortgage |
| Critical illness | A lump sum if you are diagnosed with a specified illness |
| Income protection | Higher payments need a higher monthly benefit |
| Buildings and contents | New rebuild cost and contents value, live from exchange |
Protection policies have no cash-in value at any time and will cease at the end of the term. If you stop paying premiums, your cover will end.
Wills
A new home is a good moment to check your will reflects how you own the property and who you want to inherit it.
08A move, illustrated.
A family moving up the ladder
A couple selling a £450,000 flat to buy a £650,000 house, two years into a five-year fix with a £210,000 balance.
- Deposit
- £204,720 after the sale and all moving costs
- Needed
- A £445,000 mortgage at 68.5% loan to value
- Options
- Port and top up, or a new mortgage with a £4,200 early repayment charge
- Approach
- Compared both over the deal period, including fees
- Outcome
- Ported and topped up, saving around £4,700 over two years, with sale and purchase completing the same day
This example is illustrative and does not describe a real client.
09Checklist and glossary.
Documents to have ready
- Your latest mortgage statement and any early repayment charges
- Photo ID and proof of address
- Last three months’ payslips, or accounts and SA302s
- Last three months’ bank statements
- Details of loans, credit cards and finance
- Your estate agent’s valuation or the agreed sale price
- The memorandum of sale for your purchase
- Your solicitor’s contact details
Glossary
- Porting
- Moving your existing mortgage deal to a new property.
- Top-up
- Extra borrowing alongside a ported mortgage.
- ERC
- Early repayment charge for leaving a deal early.
- Chain
- Linked sales and purchases that depend on each other.
- Exchange
- The point at which the contracts become binding.
- Completion
- Money changes hands and you get the keys.
- Bridging loan
- Short-term borrowing until a sale completes.
- LTV
- Loan to value: the loan as a percentage of the property’s value.
Related: Refinance / Additional Borrowing · All guides · Calculators