UK SDLT calculator
A 400,000 pound home bought as a standard purchase owes 10,000 pounds in stamp duty, an effective 2.5%. Each slice of the price is taxed at its own 2025-26 band, with first-time and second-home rules built in. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Price
- 400,000
- Buyer type
- Standard
- Relief
- none
- Schedule
- 2025-26
- Nil rate band
- 125,000
- Surcharge
- 0
Stamp Duty Land Tax is the United Kingdom levy on land and property purchases in England and Northern Ireland, charged on slices of the consideration rather than as a single flat percentage of the whole price. This UK stamp duty calculator accepts a property price, a buyer type (standard residential, additional dwelling, or non-residential), and a first-time-buyer flag, then walks the statutory 2025-26 bands and returns the tax amount. First-time buyer relief applies only on a standard residential purchase of five hundred thousand pounds or less; additional dwellings take a five percent surcharge on every band.
What UK Stamp Duty Land Tax is and how the 2025-26 bands add up
Stamp Duty Land Tax in England and Northern Ireland is a progressive tax on the consideration paid for land and buildings. Progressive means each pound sits in one statutory band and takes only that band's rate; buying a more expensive home does not re-tax the earlier slices at the top rate.
From 1 April 2025 the standard residential table, which this calculator freezes as schedule 2025-26, is nil on the first one hundred twenty-five thousand pounds, two percent on the next slice through two hundred fifty thousand, five percent on the portion from two hundred fifty thousand and one through nine hundred twenty-five thousand, ten percent on the portion from nine hundred twenty-five thousand and one through one million five hundred thousand, and twelve percent on anything above one million five hundred thousand.
First-time buyer relief, available only when the purchase is a standard residential main home costing five hundred thousand pounds or less, lifts the nil-rate band to three hundred thousand pounds and charges five percent on the remainder through five hundred thousand.
If the price is over five hundred thousand the relief is withdrawn entirely and standard bands apply to the whole consideration, which is why a first-time buyer at five hundred thousand pounds pays ten thousand pounds while a first-time buyer at five hundred fifty thousand pays the ordinary seventeen thousand five hundred. Additional dwellings, including most second homes and buy-to-lets, add a five percent surcharge to every standard band, so the first slice already takes five percent instead of nil.
Non-residential and mixed-use land uses a shorter table: nil through one hundred fifty thousand, two percent through two hundred fifty thousand, and five percent above that. The tax amount is the sum of slice times rate, rounded half-up to two decimal places in pounds sterling. Scotland charges Land and Buildings Transaction Tax and Wales charges Land Transaction Tax; those regimes are out of scope here.
What to enter and what you get back
If the price is over that cap, or if the buyer type is additional or non-residential, first-time buyer relief is not applied and relief is none. A four hundred thousand pound standard purchase therefore pays nil on the first one hundred twenty-five thousand, two percent of the next one hundred twenty-five thousand, and five percent of the remaining one hundred fifty thousand, for a tax of ten thousand pounds. Failed validation is not billed.
The path never calls a revenue service, never samples randomness, and never reads the system clock, so goldens compare byte-for-byte when they pin the same price and flags.
Where a UK stamp duty calculator earns its keep
Home buyers and movers use a stamp duty calculator when an offer price, a first-time buyer claim, or a second-home surcharge needs a concrete tax amount, not a slogan about the twelve percent top band. Estate agents and conveyancing desks embed the same three fields so a slider on purchase price updates tax and effective rate without a spreadsheet of five residential rows plus a surcharge toggle.
Educators and exam writers need an oracle that rejects a non-positive price instead of silently returning a zero tax that a buggy grader might treat as a free transfer. Newsrooms covering the April 2025 return of the one hundred twenty-five thousand pound nil-rate band, or the five hundred thousand pound first-time buyer cliff, can quote a deterministic bill at a stated price.
Pin the rounded tax field in tests, keep requests to a positive price plus the two flags, and you get reproducible UK stamp duty figures for articles, classrooms, and automations without standing up a private tax engine of your own.
FAQ
What happens if the price is not a positive number?
Zero, negative, missing, and non-numeric prices are rejected and are not billed.
When does first-time buyer relief apply?
Above £500,000 the relief is withdrawn and standard bands apply to the whole price.
How is an additional dwelling charged?
First-time buyer relief is not applied to additional or non-residential purchases.
How much stamp duty is due on a 400,000 pound home?
On a standard purchase without first-time relief, it is 10,000 pounds: nothing on the first 125,000, 2% on the next slice and 5% on the rest. That works out to an effective rate of 2.5%.
Does the calculator cover Scotland or Wales?
No. It applies the rules for England and Northern Ireland only. Scotland and Wales charge their own property transaction taxes, which are outside this calculator.
Related tools
For developers — API access
Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.
API endpoint
Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.
Call it from your stack
curl -X POST https://api.kit.forhosting.com/fin/sdlt-uk \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"price":400000}'const res = await fetch("https://api.kit.forhosting.com/fin/sdlt-uk", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"price": 400000
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/fin/sdlt-uk",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"price": 400000
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/fin/sdlt-uk", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"price":400000}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"price":400000}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/fin/sdlt-uk", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"price": 400000
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "fin.sdlt_uk",
"status": "queued",
"_links": {
"result": "/tasks/tsk_…/result"
}
}The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.
Pricing
Published price — no tokens, no invented credits. A failed task is never charged.
Errors
| HTTP | Code | Meaning |
|---|---|---|
401 | unauthorized | Missing or invalid API key. |
402 | insufficient_balance | Your balance doesn't cover the task price. |
404 | unknown_type | That task type doesn't exist. |
429 | rate_limited | Too many requests. Use the webhook instead of polling. |
Technical notes
A price that is not a positive finite number fails with invalid_input instead of inventing a zero bill.
What UK Stamp Duty Land Tax is and how the 2025-26 bands add up
The endpoint is a transparent band engine, not tax advice, and it is not a substitute for HM Revenue and Customs or a licensed conveyancer.
Input contract, response shape, and error behaviour
POST a JSON body with one required field and two optional flags. price is the property purchase price, the consideration in pounds sterling; aliases amount, consideration, purchase_price, property_price, and value are accepted so spreadsheets can reuse familiar column names. The value must be a finite number strictly greater than zero: a missing field, an empty string, a non-finite value such as NaN or Infinity, zero, or a negative amount fails with invalid_input naming price and stating that a positive number is required. buyer_type is an enumerated string that defaults to standard: send standard for an ordinary residential main home, additional for a second home, buy-to-let, or other additional dwelling, and non_residential for commercial or mixed-use land. first_time_buyer is a boolean that defaults to false; when it is true, buyer_type is standard, and price is five hundred thousand pounds or less, the first-time buyer table is used and relief is reported as first_time_buyer. When validation passes, the body echoes price rounded half-up to two decimals, buyer_type, and first_time_buyer, then returns schedule 2025-26, nil_rate_band, surcharge in percentage points (five for additional, otherwise zero), tax in pounds, effective_rate as a percent of price to four decimal places, and a formula string restating the band identity.
Where a UK stamp duty calculator earns its keep
Landlords comparing a buy-to-let against a main-home purchase can flip buyer_type from standard to additional and see the five percentage-point extra on every band, including the first slice that standard buyers take at nil. Every successful API call costs the published $0.002 base price with no model tokens and no outbound network; invalid input does not consume balance. When you later layer a non-resident surcharge, a company fifteen percent enveloped-dwelling rate, or a main-residence replacement exception in a workbook, keep this endpoint on the documented buyer types so the published 2025-26 table stays comparable to the HMRC bands it cites.
Integration use cases
Main-home offer and budget check
Enter a purchase price with buyer_type standard to see SDLT due under the 2025-26 residential bands before you raise an offer or instruct a solicitor.
First-time buyer relief versus the £500,000 cliff
Set first_time_buyer true on a standard purchase of £500,000 or less to apply the 0% / 5% relief table, and see relief withdrawn when the price crosses five hundred thousand pounds.
Second home and buy-to-let surcharge
Flip buyer_type to additional to add five percentage points on every band, including the first slice, when modelling a second home or a buy-to-let.
Technical questions
How is UK Stamp Duty Land Tax calculated?
Send a positive price in pounds, an optional buyer_type (standard, additional, or non_residential), and optional first_time_buyer. The API walks the 2025-26 bands and returns tax as the progressive sum of each slice times its rate.
What does the UK stamp duty calculator cost?
The browser tool is free. API requests use prepaid KIT balance at $0.002 per successful call; invalid input is not billed.