Updated on 6 April 2026

High income child benefit charge: moving in with a partner

If you move in with your partner, this can trigger the high income child benefit charge (often referred to as HICBC). We explain how this works and provide information on completing the high income child benefit charge section of your Self Assessment tax return in these cases. This is a complex area. We aim to provide a general overview, but would recommend that you take specific advice if you move in with a child benefit claimant during the year and become liable to the HICBC.

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Effect on liability to the high income child benefit charge

If you are in a relationship with another person during a tax year and:

one (or both) of you has adjusted net income which is over the relevant threshold for that year (since 2024/25 this has been £60,000, prior to that it was £50,000), and
one (or both) of you claims child benefit in that year,

then you will need to determine for each week whether that other person is your ‘partner’ for high income child benefit charge purposes.

As we explain in more detail at High income child benefit charge: issues on separation, you are someone else’s partner for this purpose if, for a given week, either:

you are married (or in a civil partnership) and not separated under a court order or separated in circumstances likely to be permanent, or
you are not married (or in a civil partnership) but you are living together as if you are married.

It is therefore often (though not always) the point when you move in with a partner which will mean you start to be treated as partners for the purposes of the high income child benefit charge.

Calculating the high income child benefit charge

Calculating the high income child benefit charge when you have moved in with a partner during the tax year can be quite complicated. In any situation where you are unsure, we recommend you seek advice.

There are several different scenarios that might arise when you move in with a partner, depending on your circumstances. We explain some possible scenarios below.

Note that the person who is the ‘child benefit claimant’ is the person who made the claim. The high income child benefit charge rules consider the claimant (and any partner they may have) when determining who is liable to pay the charge. The claimant may not be the same as the person who receives the payments – for example, if they are paid into a different bank account, such as one of an ex-partner, or joint bank account.

Each of the below scenarios assume that you become partners for the purposes of the high income child benefit charge from the point you move in with each other, and that you remain so for the remainder of the tax year.

For the purposes of these scenarios, the relevant threshold is £60,000 for tax years from 2024/25, and £50,000 for tax years up to and including 2023/24.

Scenario A

Your adjusted net income for the full year is less than the relevant threshold, but your partner’s is more than that threshold. You are the child benefit claimant for the full year. In this case, the child benefit entitlement for the weeks of the year after moving in together is used to calculate the high income child benefit charge payable by your partner, based on their adjusted net income for the full year.

Scenario B

The same as Scenario A, except that your partner is the child benefit claimant for the full year. In this case, the child benefit entitlement for the full year is used to calculate the high income child benefit charge payable by your partner, based on their adjusted net income for the full year. The moving in date is irrelevant.

Scenario C

Your adjusted net income for the year is more than the relevant threshold, but your partner’s is less than that threshold. You are the child benefit claimant for the full year. In this case, the child benefit entitlement for the full year is used to calculate the high income child benefit charge payable by you, based on your adjusted net income for the full year. The moving in date is irrelevant.

Scenario D

The same as Scenario C, except that your partner is the child benefit claimant for the full year. In this case, the child benefit entitlement for the weeks of the year after moving in together is used to calculate the high income child benefit charge payable by you, based on your adjusted net income for the full year.

Other scenarios

More complex scenarios may include the following:

Both you and your partner’s adjusted net income exceeds the relevant threshold for the year.
Each person in a relationship claims child benefit for their own child(ren).
The child benefit payments stop or start in the year, or they are backdated.
There is an ex-partner prior to the move-in date with adjusted net income for the year of more than the relevant threshold.
Contributions are made towards the upkeep of a child from an ex-partner.
You separate before the end of the tax year.

As already mentioned, we recommend you get tax advice if you have moved in with a partner during the year and are subject to the high income child benefit charge.

Example – high income child benefit charge when moving in together

Aaron and Kerry moved in together as partners on 1 June 2025. Kerry has a daughter from a previous relationship and receives child benefit payments. Aaron’s adjusted net income for 2025/26 was £65,000 and Kerry’s was £28,000.

Since Aaron’s adjusted net income for the 2025/26 tax year was more than £60,000 (the relevant threshold for that year) he will be liable to the high income child benefit charge. He is only liable to pay the charge in respect of Kerry’s child benefit entitlement from the date they moved in together – not for the whole tax year.

Aaron doesn’t need to file a Self Assessment tax return and so decides to pay the charge through PAYE. He must notify HMRC of this by 31 January 2027, and he does so online at GOV.UK. You can read more about how to pay the charge in our general guidance on the high income child benefit charge.

Income changes

As highlighted above, your income level for the high income child benefit charge is always assessed based on your income for the entire tax year – not simply your income for the period during which child benefit is taken in account when calculating the charge, if that is different.

The below example shows how this can lead to counter-intuitive results.

Example – income for the entire tax year

Gale and Cameron had been in a relationship with each other for two years before moving in together on 6 October 2025. They are treated as partners for the purposes of the high income child benefit charge with effect from this date. Cameron has a child from a previous relationship and claims child benefit for that child.

At the start of the 2025/26 tax year, Gale was employed full-time on an annual salary of £68,000 and he has no deductible pension contributions. Cameron’s annual salary is £51,000. They have never previously had to consider the high income child benefit charge.

When they move in, Gale decides to work four days a week and his new annual salary from 6 October 2025 is £54,400.

Gale’s total income for the 2025/26 tax year is as follows:

Salary from full-time job up to 5 October 2025: £68,000 x 6/12 months = £34,000

Salary from part-time job from 6 October 2025: £54,400 x 6/12 months = £27,200

Total Income: £61,200

Based on Gale’s total income of £61,200 for the 2025/26 tax year, he is liable to the high income child benefit charge because it exceeds the £60,000 threshold. The charge applies despite the fact his annualised salary during the period after he moved in with Cameron was below the relevant threshold for 2025/26 (£60,000). Only the child benefit paid to Cameron in the part of the year after he moved in with Gale is brought into account when calculating the charge.

Completing your tax return

If you pay your high income child benefit charge through Self Assessment and not through PAYE, care is needed when completing your tax return. HMRC’s current Self Assessment tax return guidance notes on GOV.UK set out how you should complete the tax return if you are liable to the high income child benefit charge and you have moved in with your partner during the tax year. When answering the questions on the tax return take care to ensure that the total child benefit for period when you were living together is entered.

In some cases, we are aware that answering the questions in the relevant sections of the tax return literally may lead to an incorrect high income child benefit charge being calculated by HMRC or by third-party software. For example, the child benefit entitlement for the full year may be taken into account in the calculation, when only in fact only part-year entitlement should be used. You should therefore independently check that the charge which has been calculated for you is correct by following the guidance on this page.

If you feel the high income child benefit charge which has been calculated is incorrect, we suggest you contact HMRC.

You may decide to complete the boxes on the return in such a way that HMRC’s online systems (or third-party software) calculates the high income child benefit charge which you believe to be correct, even if that involves interpreting the boxes in a non-literal way. However, if you choose to do this, we recommend you seek advice first and provide a full disclosure of how you have interpreted the relevant boxes in the ‘Any other information’ section of the return.

Strictly speaking, you cannot appeal a calculation of your tax liability that you submit with your own Self Assessment tax return, even if it is calculated by HMRC’s online systems. You should therefore ensure that the calculation of tax owed is correct prior to submission. However, it is possible to amend a Self Assessment (including the calculation) within the usual time limits, if you later realise it is incorrect.

If you submitted your Self Assessment tax return online then the guidance on GOV.UK says you should update your tax return online if you wish to make an amendment. However, if you feel your return is correct but you wish to challenge the calculation of the HICBC, you may need instead to write to HMRC or contact them by telephone.

If you think you have paid too much

If you are liable to the high income child benefit charge and are worried that you may have paid too much in light of the information given above, we suggest you contact HMRC for advice.

You can read more about amending a tax return on our page Amending a tax return and on GOV.UK.