How is Multiple Dwellings Relief calculated for Welsh Land Transaction Tax?

Introduction

Buyers sometimes discover that the Welsh Revenue Authority’s calculation of Land Transaction Tax (LTT) under Multiple Dwellings Relief (MDR) does not match the figure they expected. This usually happens because MDR is not calculated by simply reducing the total tax bill in a broad or intuitive way. Instead, it follows a specific statutory method.

This article explains how the MDR calculation works in Wales, using a generalised example based on a query about a purchase of two dwellings for a single total price. It also explains why a taxpayer may think they have overpaid, but still need to check the official calculation carefully against the statutory steps and any applicable minimum tax rule.

The Question

A taxpayer bought two dwellings in Wales in a single transaction for a total consideration of £679,000. Higher residential rates were thought to apply. The taxpayer had originally paid LTT of £58,035 and later argued that, if MDR applied, the correct LTT should have been £40,350, producing an overpayment and a potential refund.

The issue was whether that £40,350 figure was correct under the Welsh MDR rules, or whether the Welsh Revenue Authority’s own calculation under its technical guidance would produce a different result.

Nick’s Explanation

Nick’s reasoning followed the four-step method described in Welsh Revenue Authority guidance LTTA/7038.

In summary, his position was:

• take the total consideration for the dwellings, £679,000;
• divide it by the number of dwellings, assumed to be 2, giving an average of £339,500 per dwelling;
• calculate LTT on that average figure using the higher residential rates in force at the time;
• multiply that amount by 2, giving a total MDR liability of £40,350;
• because there were said to be no linked transactions and no non-dwelling consideration, the figure would remain unchanged.

His conclusion was that if the original LTT paid was £58,035, then the difference of £17,685 would appear to be repayable.

The important point in Nick’s explanation is that MDR depends on a structured formula. If the number of dwellings, the rate table, or any part of the consideration has been treated differently by the Welsh Revenue Authority, the final figure can change.

The Law

Multiple Dwellings Relief for Welsh LTT is governed by the Land Transaction Tax and Anti-avoidance of Devolved Taxes (Wales) Act 2017 and the Welsh Revenue Authority’s published technical guidance, including LTTA/7038.

In broad terms, where MDR is available, the tax related to dwellings is calculated by:

1. dividing the relevant dwellings consideration by the number of dwellings;
2. calculating the tax on that average amount as if it were a single dwelling purchase;
3. multiplying that tax by the number of dwellings;
4. for linked transactions, apportioning the result using the statutory fraction CD ÷ TDC.

The guidance also makes clear that:

• higher residential rates will generally apply in calculating the dwellings part where those rates are otherwise engaged;
• if there is remaining consideration not attributable to dwellings, that may need a separate calculation;
• a minimum tax rule may apply, so that the tax payable under MDR cannot fall below the statutory minimum where relevant.

Whether there are in fact “multiple dwellings” is a separate legal question from how the relief is calculated. In some cases, a taxpayer may also argue that part of a property was not suitable for use as a dwelling. For that kind of argument, the threshold is now relatively high following Amarjeet and Tajinder Mudan v The Commissioners for HMRC [2025] EWCA Civ 799. A property generally needs to be in genuinely serious condition before it will fail the “suitable for use” test.

Analysis

The correct approach is to work through the MDR method in order.

Step 1: identify the total dwellings consideration

If the whole £679,000 was attributable to two dwellings, and there was no non-residential element and no separate remaining consideration, the starting figure for the dwellings calculation would be £679,000.

Step 2: divide by the number of dwellings

On the assumption that there were two qualifying dwellings, the average consideration would be:

£679,000 ÷ 2 = £339,500

Step 3: calculate the tax on that notional single dwelling

This is the critical stage. The tax must be calculated using the rate bands in force on the effective date of the transaction and using the correct rate table, usually the higher residential rates if those applied to the transaction.

If that tax on £339,500 is calculated at about £20,175, then multiplying by two gives £40,350. That is the basis of the taxpayer’s argument.

Step 4: multiply by the number of dwellings

If the single-dwelling notional tax is £20,175, then:

£20,175 × 2 = £40,350

Step 5: check whether step 4 of the statutory method is needed

Where there are linked transactions, the legislation requires the additional CD ÷ TDC adjustment. But if this was a single standalone transaction and all consideration related to the same two dwellings, that fraction would effectively be 1, so it would not alter the result.

Step 6: check the minimum tax rule

In some cases MDR produces a very low figure, and the statutory minimum tax rule then replaces it. On the facts described here, that does not appear to be the source of the disagreement, because the disputed figures are well above any 1% minimum issue.

Step 7: check whether the assumptions are actually correct

This is where disagreements usually arise. The Welsh Revenue Authority may have reached a different figure because one or more of these assumptions was different:

• it may not have accepted that there were two qualifying dwellings;
• it may have used a different effective date and therefore different rates;
• it may have treated part of the consideration as not attributable to dwellings;
• it may have considered there to be linked transactions;
• it may have found an arithmetic error in the taxpayer’s rate calculation.

So although the taxpayer’s £40,350 figure follows the published method in principle, the result only stands if every underlying input is correct.

Outcome

If a buyer acquired two qualifying dwellings in a single non-linked Welsh transaction for £679,000, and the whole of that consideration was attributable to the dwellings, and the higher residential rates used in the calculation were the correct rates for the effective date, then an MDR figure of £40,350 may be a plausible result.

However, a taxpayer should not assume that this automatically proves an overpayment. The final answer depends on whether the number of dwellings, the rate table, and the treatment of the consideration all match the statutory rules and the Welsh Revenue Authority’s guidance.

If the Welsh Revenue Authority says the amount “differs from our calculations”, the practical next step is to identify exactly which input or step differs.

Practical Steps

• Confirm the effective date of the transaction, because the LTT rates in force on that date matter.
• Check that there were in law two separate dwellings for MDR purposes.
• Confirm whether the whole purchase price was attributable to dwellings, or whether any part related to other land or assets.
• Check whether the transaction was linked to any other acquisition.
• Recalculate the tax using LTTA/7038 and the Welsh Revenue Authority MDR calculator.
• Ask the Welsh Revenue Authority to explain which precise figure in the calculation it disputes: the number of dwellings, the average consideration, the rate applied, or the final multiplication.
• If the issue is whether part of the property was not suitable for use as a dwelling, assess that point carefully in light of Amarjeet and Tajinder Mudan v The Commissioners for HMRC [2025] EWCA Civ 799, because the threshold is now relatively high.

Conclusion

MDR for Welsh LTT is formula-driven. A figure such as £40,350 can be correct if the transaction facts and rate assumptions are right, but the calculation only works if the dwelling count, consideration, and applicable rates are all correct. Where the Welsh Revenue Authority disagrees, the real issue is usually not the formula itself, but one of the inputs to that formula.

Legal References Used

• Land Transaction Tax and Anti-avoidance of Devolved Taxes (Wales) Act 2017
• Welsh Revenue Authority technical guidance LTTA/7038: Calculation of LTT liability: determining the tax related to consideration attributable to dwellings
• Land Transaction Tax relief for acquisitions involving multiple dwellings: technical guidance | GOV.WALES
• Amarjeet and Tajinder Mudan v The Commissioners for HMRC [2025] EWCA Civ 799

This page was last updated on 22 March 2026.

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