About the UK Stamp Duty Calculator
Stamp duty land tax on a property purchase, band by band.
There is a piece of folk knowledge about stamp duty that used to be true and is now wrong: that going a pound over a threshold re-rates your whole purchase and costs you thousands.
That stopped being true in 2014. Stamp duty is now progressive — each band charges only the slice of the price inside it, exactly like income tax. For an ordinary purchase there is no threshold worth avoiding and no dead zone above any round number.
With one exception, which is real, which is large, and which this stamp duty calculator exists to catch.
How to Use the UK Stamp Duty Calculator
Enter the purchase price and say who is buying — moving home, a first-time buyer, or an additional property.
Every threshold and rate is editable. They move often, sometimes temporarily, and a calculator with them baked in goes quietly out of date.
Step-by-Step Example
£400,000, moving home.
First 125,000 at 0% = 0
125,000 to 250,000 at 2% = 2,500
250,000 to 400,000 at 5% = 7,500
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Stamp duty: 10,000
Total with the price: 410,000Effective rate 2.5% of the price. Marginal rate 5%.
Note the effective rate — 2.5%, not the 5% band the buyer is "in". Quoting the band rate as though it applied to the whole price doubles the figure.
The One Genuine Cliff
First-time buyer relief is all or nothing.
Up to the relief limit, a first-time buyer pays a reduced schedule. One pound above it, the relief does not shrink — it disappears, and the standard schedule applies to the entire purchase.
First-time buyer at 500,000: 10,000
First-time buyer at 500,001: 15,000.05
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One pound of price: 5,000.05 of taxThis is a slab sitting inside an otherwise progressive tax, and it is the only place in stamp duty where a buyer should genuinely care about a round number.
Negotiating Down Can Be Worth More Than the Discount
The consequence is worth spelling out, because it inverts the usual logic of haggling.
At £502,000, a first-time buyer pays £15,100 of stamp duty. Drop the price to £500,000 and the duty falls to £10,000.
Price saved: 2,000
Tax saved: 5,100
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Total saved: 7,100A £2,000 reduction is worth £7,100. The calculator detects when your price sits inside that range and tells you what the move is worth, because a buyer who does not know about the cliff will not think to ask.
The range is roughly the size of the cliff itself — a few thousand pounds above the limit. Beyond it, the arithmetic goes back to normal.
The Surcharge Works Backwards From What People Expect
The additional property surcharge is not charged on a slice above some threshold. It is added to every band, so it applies to the whole price from the very first pound.
| £300,000 purchase | Duty |
|---|---|
| Moving home | £5,000 |
| Additional property | £20,000 |
The surcharge portion is £15,000 — exactly 5% of the full £300,000, not 5% of some upper slice.
It also applies inside the nil rate band. A £100,000 second home pays £5,000 of duty even though a mover would pay nothing at all. Only purchases below £40,000 escape it entirely.
First-Time Buyers Do Not Pay Nothing
A common half-truth. The relieved schedule charges nothing up to its nil rate band, then 5% between that and the relief limit.
| Price | First-time buyer | Moving home |
|---|---|---|
| £300,000 | £0 | £5,000 |
| £400,000 | £5,000 | £10,000 |
| £500,000 | £10,000 | £15,000 |
| £500,001 | £15,000.05 | £15,000.05 |
The relief is worth a flat £5,000 across most of its range — and then, at the limit, it is worth nothing at all.
Why Every Threshold Is an Input
The nil rate band, the first-time buyer limits and the surcharge rate have all changed in recent years. Several changes were temporary and reverted.
A calculator with those figures hard-coded is correct for one period and then silently wrong, with nothing to indicate it has gone stale. Here they are inputs, and the size of the cliff is computed from whatever you enter rather than quoted — so if the limit moves, the warning moves with it.
Understanding Your Result
Stamp duty is the tax itself.
Total cost adds it to the price, before legal fees and survey.
Band by band shows the slice falling into each band, which is what makes the progressive structure visible.
Effective and marginal gives the rate across the whole price and the rate on the next pound. They are very different, and quoting the band rate as the effective rate is the commonest error.
Worth knowing flags the cliff, the danger zone, or the surcharge.
When Should You Use This Calculator?
Before making an offer. Particularly as a first-time buyer near the relief limit.
When the offer lands just over a round number. The cliff may be worth more than the negotiation.
Budgeting a purchase. Stamp duty is paid in cash and cannot normally be added to the mortgage.
Comparing a second home. The surcharge changes the sums substantially.
Common Mistakes
Believing a threshold re-rates the whole price. It has not since 2014 — except for first-time buyer relief.
Applying your band rate to the whole price. At £400,000 the band is 5% and the effective rate is 2.5%.
Assuming first-time buyer relief tapers. It vanishes, and that is the one cliff.
Thinking the surcharge applies only above a threshold. It is added to every band, including the nil rate one.
Assuming first-time buyers pay nothing. They pay 5% above the relieved nil rate band.
Forgetting stamp duty is cash. It generally cannot be borrowed against the property.
Using an old schedule. The thresholds move, which is why they are inputs here.
Rates, thresholds and reliefs are set by the government and change, sometimes temporarily. Scotland and Wales operate separate taxes with different bands. Every figure here is an estimate for planning, not tax advice — check with HMRC or a conveyancer before relying on it.