Tax Code changed - expected to owe tax

DRS1

As the title says my tax code has been changed part way through the tax year (25/6) and it says I am expected to owe a certain amount of tax as a result which will be collected after 6 April 2026 by adjusting the tax code for 26/7 (adjusting my tax free allowance for that year).

I suspect they won't be able to do that as my tax free allowance is 0 and likely to stay that way.

But I thought no problem because it will all get taken into account when I do my self assessment for 25/6.  The tax they expect me to owe will form part of the balancing payment due in January 2027.

But what will actually happen to my PAYE deductions from April 2026 onward?  Will I see figures for underpaid tax appear?

In my self assessment for 25/6 will I need to fill in any of the boxes about underpaid tax?  I assume not because it is only tax I am "expected to owe"

I am wondering if there is anything to worry about or not.

Isthisforreal99

DRS1 said:

As the title says my tax code has been changed part way through the tax year (25/6) and it says I am expected to owe a certain amount of tax as a result which will be collected after 6 April 2026 by adjusting the tax code for 26/7 (adjusting my tax free allowance for that year).

I suspect they won't be able to do that as my tax free allowance is 0 and likely to stay that way.

But I thought no problem because it will all get taken into account when I do my self assessment for 25/6.  The tax they expect me to owe will form part of the balancing payment due in January 2027.

But what will actually happen to my PAYE deductions from April 2026 onward?  Will I see figures for underpaid tax appear?

In my self assessment for 25/6 will I need to fill in any of the boxes about underpaid tax?  I assume not because it is only tax I am "expected to owe"

I am wondering if there is anything to worry about or not.

You can have negative allowances, known as a K code so the potential 25/26 underpayment can be collected through your 26/27 tax code.

When you complete your 25/26 return there will be a box that says (to the affect) "Underpaid tax for 2025/26 included in your tax code for 26/27"

Dazed_and_C0nfused

DRS1 said:

As the title says my tax code has been changed part way through the tax year (25/6) and it says I am expected to owe a certain amount of tax as a result which will be collected after 6 April 2026 by adjusting the tax code for 26/7 (adjusting my tax free allowance for that year).

I suspect they won't be able to do that as my tax free allowance is 0 and likely to stay that way.

But I thought no problem because it will all get taken into account when I do my self assessment for 25/6.  The tax they expect me to owe will form part of the balancing payment due in January 2027.

But what will actually happen to my PAYE deductions from April 2026 onward?  Will I see figures for underpaid tax appear?

In my self assessment for 25/6 will I need to fill in any of the boxes about underpaid tax?  I assume not because it is only tax I am "expected to owe"

I am wondering if there is anything to worry about or not.

Are you already registered for Self Assessment?

If so what exactly does the message on your tax code say?  I didn't think the next year's tax code was changed in the scenario you have outlined, the actual extra tax due all forming part of your 2025/26 Self Assessment calculation.

DRS1

Dazed_and_C0nfused said:

DRS1 said:

As the title says my tax code has been changed part way through the tax year (25/6) and it says I am expected to owe a certain amount of tax as a result which will be collected after 6 April 2026 by adjusting the tax code for 26/7 (adjusting my tax free allowance for that year).

I suspect they won't be able to do that as my tax free allowance is 0 and likely to stay that way.

But I thought no problem because it will all get taken into account when I do my self assessment for 25/6.  The tax they expect me to owe will form part of the balancing payment due in January 2027.

But what will actually happen to my PAYE deductions from April 2026 onward?  Will I see figures for underpaid tax appear?

In my self assessment for 25/6 will I need to fill in any of the boxes about underpaid tax?  I assume not because it is only tax I am "expected to owe"

I am wondering if there is anything to worry about or not.

Are you already registered for Self Assessment?

If so what exactly does the message on your tax code say?  I didn't think the next year's tax code was changed in the scenario you have outlined, the actual extra tax due all forming part of your 2025/26 Self Assessment calculation.

Yes I have been doing self assessment for years.  It is PAYE which is new to me.

The Note says

Due to an in year adjustment to your tax code(s) we think that you will owe HMRC £x.  We will therefore include an adjustment to reduce your tax free allowance to collect the £x in equal instalments by increasing the tax deducted from your wage, salary or pension from 6 April 2026.

When I looked at the note for the underpaid tax boxes on the SA form I think that said something about collection through self assessment instead of the tax code adjustment.