What is Stamp Duty Land Tax?

Stamp Duty Land Tax (SDLT) is a tax paid by buyers of property and land in England and Northern Ireland, calculated as a percentage of the purchase price, with different rates applying to different portions of the price in a tiered "banded" structure — similar in concept to how income tax bands work. Scotland has its own equivalent (Land and Buildings Transaction Tax) and Wales has its own (Land Transaction Tax), each with different thresholds, which this calculator does not cover.

How the banded system works

Rather than a single flat rate applying to the whole purchase price, SDLT is charged in bands: you pay 0% on the portion of the price within the lowest band, then progressively higher rates on each portion of the price that falls into higher bands, similar to how income tax is calculated on portions of your salary rather than your whole income at one marginal rate.

Worked example (home mover, no first-time buyer relief): On a £320,000 purchase, you'd pay 0% on the first £250,000, then 5% only on the remaining £70,000 — not 5% on the whole £320,000. This banded structure is why a modest increase in purchase price near a band threshold has a smaller marginal impact than many buyers initially assume.

First-time buyer relief

First-time buyers benefit from a more generous starting band, paying 0% SDLT up to a higher threshold than home movers, with relief available up to a set overall property price limit. Above that upper limit, first-time buyer relief no longer applies, and standard rates are charged on the whole amount instead. This relief reflects a deliberate government policy choice to support access to homeownership for first-time buyers specifically.

The additional property surcharge

Buyers purchasing an additional residential property — most commonly a buy-to-let investment or a second home — pay a surcharge on top of the standard banded rates, applied across the entire purchase price rather than just the amount above a threshold. This surcharge exists specifically to moderate demand for additional residential property from investors and second-home buyers relative to owner-occupier first-time buyers and home movers, and it's a meaningful additional cost that should always be factored into a buy-to-let investment's overall return calculation — see our buy-to-let mortgage rules guide for the fuller financial picture.

Why this calculator matters for budgeting

Stamp Duty is due shortly after completion (typically within 14 days) and must be paid in cash — it cannot usually be added to your mortgage borrowing. This makes it an essential figure to budget for alongside your deposit, since underestimating it can create a genuine cash flow problem at exactly the point you're already managing moving costs, legal fees and other completion-day expenses.

Rates and thresholds change — always verify before exchange

UK Stamp Duty thresholds and rates are set by government policy and have changed multiple times in recent years, including temporary adjustments during specific periods. This calculator uses a standard illustrative band structure for general guidance, but you should always confirm the exact current thresholds directly via HMRC's official Stamp Duty calculator or with your solicitor before exchanging contracts, since the actual amount due depends on the rules in force at your specific completion date.

How solicitors handle SDLT in practice

In almost all UK property transactions, your solicitor or conveyancer handles the SDLT return and payment on your behalf as part of the completion process, using the funds you provide alongside your deposit. It's worth asking your solicitor to confirm the exact SDLT liability specific to your purchase well before completion, so there are no last-minute surprises about the total cash required.

Related reading: How Much Deposit Do You Need for a UK Mortgage?.

The bottom line

Stamp Duty can represent a genuinely significant upfront cost — particularly for buy-to-let purchases subject to the additional surcharge — and it's a cash cost that sits alongside, not as part of, your mortgage deposit. Use this calculator to get a realistic early estimate, then always confirm the precise figure with your solicitor or HMRC's own calculator before exchange, given how frequently thresholds have changed in recent years.

This calculator provides estimates for general information only and is not a mortgage or loan offer, quotation or financial advice. Actual rates, fees and lending decisions depend on the lender's own criteria and a full affordability assessment. See our full terms and disclaimer.