How is stamp duty calculated?

It is charged in slices, not as one rate on the whole price. Nothing is due on the first 125,000 pounds, then 2 percent to 250,000, then 5 percent to 925,000, then 10 percent to 1.5 million and 12 percent above that. A 300,000 pound purchase therefore costs 5,000 pounds, not 15,000.

What relief do first-time buyers get?

First-time buyers pay nothing on the first 300,000 pounds and 5 percent on the slice up to 500,000, and above 500,000 the relief disappears entirely. This calculator does not model that relief — there is no first-time buyer option, so it always shows the standard rates. Work your own figure from those two bands if the relief applies to you.

Does this cover Scotland and Wales?

No. Scotland charges Land and Buildings Transaction Tax and Wales charges Land Transaction Tax, both with different bands. This calculator covers England and Northern Ireland only, and the stamp duty row says so.

Why does loan-to-value matter so much?

UK lenders price in bands, and the cliff edges are at 90, 85, 80 and 75 percent. Getting your deposit just over one of those lines can cut the rate you are offered, which is worth more than a small change in the price you negotiate.

Is this a repayment or interest-only mortgage?

Repayment. The figure clears the whole balance over the term you enter, which is how almost all UK residential mortgages now work. Interest-only would be lower each month but would leave the full balance outstanding at the end.

Should I use a 25 or 30 year term?

Twenty-five years is the traditional default and is what this calculator assumes. A longer term lowers the monthly payment and raises the total interest substantially. Change the term field and watch the total interest row rather than only the monthly one.

Do I need the deposit and the stamp duty in cash?

Yes, both. On the default example that is 45,000 pounds of deposit plus 5,000 pounds of duty, and you will also need survey and legal fees on top. Stamp duty cannot be added to the mortgage.

UK Mortgage Calculator

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UK mortgage repayment & Stamp Duty

Property price (£)Deposit saved (£)Interest rate (%)Mortgage term (yrs)

Monthly repayment£1,520.57
Mortgage amount needed£255,000
Loan-to-Value (LTV)85.00%
Stamp Duty (SDLT) estimate£5,000
Total interest over term£201,171

Calculated in your browser — nothing you type is sent anywhere.

Repayment, loan-to-value and stamp duty in one place

Most UK mortgage calculators give you a monthly figure and stop, which leaves out the two numbers that decide whether you can actually complete: how much cash you need on the day, and which loan-to-value band you land in. This one shows all three together.

On the default example, a £300,000 property with a £45,000 deposit at 5.2 percent over twenty-five years, you borrow £255,000 and repay £1,520.57 a month. That puts you at 85 percent loan-to-value. Stamp duty is £5,000, and with the deposit on top you need £50,000 in cash before fees. Total interest over the full term is about £201,171 — noticeably more than the amount you borrowed.

Stamp duty is charged in slices

The most common mistake is applying one percentage to the whole price. Duty works like income tax: each slice of the price is taxed at its own rate. On 300,000 pounds the first 125,000 is free, the next 125,000 is charged at 2 percent, and only the last 50,000 is charged at 5 percent.

Standard rates: 0 to 125,000 nil, then 2, 5, 10 and 12 percent in bands above it.
First-time buyers: nil to 300,000 and 5 percent to 500,000, with the relief lost entirely above 500,000.
England and Northern Ireland only: Scotland and Wales use different taxes and different bands.
Payable in cash: duty cannot be added to the loan, unlike some purchase fees.

Use the loan-to-value row before you offer

Lender rates step at 90, 85, 80 and 75 percent, so a deposit that lands just above a threshold can win a better rate than a slightly lower purchase price would. Try nudging the deposit until the loan-to-value row crosses a band, then compare the monthly figure. Rates here are your input rather than a live quote, and the duty bands are those in force for England and Northern Ireland as at April 2025. Everything runs in your browser.

Frequently Asked Questions

How is stamp duty calculated?
It is charged in slices, not as one rate on the whole price. Nothing is due on the first 125,000 pounds, then 2 percent to 250,000, then 5 percent to 925,000, then 10 percent to 1.5 million and 12 percent above that. A 300,000 pound purchase therefore costs 5,000 pounds, not 15,000.
What relief do first-time buyers get?
First-time buyers pay nothing on the first 300,000 pounds and 5 percent on the slice up to 500,000, and above 500,000 the relief disappears entirely. This calculator does not model that relief — there is no first-time buyer option, so it always shows the standard rates. Work your own figure from those two bands if the relief applies to you.
Does this cover Scotland and Wales?
No. Scotland charges Land and Buildings Transaction Tax and Wales charges Land Transaction Tax, both with different bands. This calculator covers England and Northern Ireland only, and the stamp duty row says so.
Why does loan-to-value matter so much?
UK lenders price in bands, and the cliff edges are at 90, 85, 80 and 75 percent. Getting your deposit just over one of those lines can cut the rate you are offered, which is worth more than a small change in the price you negotiate.
Is this a repayment or interest-only mortgage?
Repayment. The figure clears the whole balance over the term you enter, which is how almost all UK residential mortgages now work. Interest-only would be lower each month but would leave the full balance outstanding at the end.
Should I use a 25 or 30 year term?
Twenty-five years is the traditional default and is what this calculator assumes. A longer term lowers the monthly payment and raises the total interest substantially. Change the term field and watch the total interest row rather than only the monthly one.
Do I need the deposit and the stamp duty in cash?
Yes, both. On the default example that is 45,000 pounds of deposit plus 5,000 pounds of duty, and you will also need survey and legal fees on top. Stamp duty cannot be added to the mortgage.