Stamp Duty Calculator

What Is a Stamp Duty Calculator?

Stamp duty is one of the largest upfront costs in buying property in England and Northern Ireland, and the one most buyers underestimate. First-time buyers are often surprised to discover they're not automatically exempt from the whole amount — only the first £425,000 is stamp-duty-free on properties up to £625,000. Above those thresholds, standard rates apply to the excess.

From April 2025, the thresholds reverted to pre-pandemic levels: 0% on the first £125,000, 2% on £125,001–£250,000, 5% on £250,001–£925,000, 10% on £925,001–£1.5m, and 12% above that. Additional property purchases — buy-to-let or second homes — attract a 3% surcharge on top of those rates. Overseas buyers pay a further 2% surcharge.

Enter the property price and select your buyer type. The calculator applies the correct thresholds and shows the total stamp duty figure alongside a breakdown by band.

How Do You Use This Stamp Duty Calculator?

Enter the property price and select your buyer type. The calculator applies the correct SDLT bands and any applicable relief automatically.

1. Enter the full purchase price of the property.
2. Select your buyer type: standard, first-time buyer, or additional/buy-to-let property.
3. Click Calculate to see your stamp duty bill.
4. Review the effective rate and total cost including SDLT.

How Does the Stamp Duty Calculator Formula Work?

The formula used: SDLT is calculated in bands: 0% up to £250,000; 5% on £250,001–£925,000; 10% on £925,001–£1,500,000; 12% above £1,500,000.

What Are Some Example Calculations?

A £400,000 property (standard buyer): 0% on first £250,000 = £0. 5% on remaining £150,000 = £7,500. Total SDLT = £7,500.

When Should You Use a Stamp Duty Calculator?

Before making an offer. Stamp duty must be paid at completion alongside conveyancing fees (typically £1,500–£3,000), survey costs (£400–£1,500), and moving costs. On a £350,000 home as a home mover, you'll owe £7,500 in stamp duty — money that needs to be liquid, not sitting in a 90-day notice savings account.

When buying an additional property or buy-to-let. The 3% surcharge changes the maths materially on lower-value purchases. A £200,000 buy-to-let incurs £7,500 in stamp duty versus £1,500 for a home mover buying the same property. That difference directly affects rental yield calculations and your breakeven timeline on the investment.

What Do These Terms Mean?

What Are the Best Tips to Know?

• Budget for SDLT before you make an offer — it is payable on completion and usually cannot be added to the mortgage.
• First-time buyers save the most on properties between £300,000 and £625,000.
• Buying just below a threshold (e.g., £249,999 vs £251,000) can save thousands.
• The additional property surcharge applies even if you are selling your main home but have not yet completed — you can claim a refund within 12 months if you then sell.

What Mistakes Should You Avoid?

• Treating stamp duty as a flat rate on the whole price — it uses progressive bands.
• Forgetting the 3% additional property surcharge when buying a second home.
• Assuming first-time buyer relief applies above £625,000 — it does not.
• Not budgeting for SDLT in cash — it must be paid at completion.