Calculating income for High Income child benefit charge

Hi, hopefully a straightforward question I only have one source of income but for some reason HMRC has been asking me to do a self assessment for many years now. With new changes I believe I can claim some of the child benefit but not sure what the correct figure is. On my SA102 form, is it box 1 we use to work out the earnings for the year as far as this charge is concerned or done use the figure in box 1 and take out box 2 to work it out? Does the figure in box 1 includes any deductions for my Defined Contribution employer pension usually taken before tax is applied? I have already increased my pension contributions to account for this and I reckon this year the figure in box 1 will drop to the mid £60K mark. I could increase the pension contributions even more I suppose. Thanks

Hi Michael,
From your question it would be the Higher Income Child Benefit Charge, HICBC, that is the criteria for Self Assessment.
You can check if you meet the criteria here:
Check if you need to send a Self Assessment tax return
It would be the figure in box 1.
If you pay into a company pension and the contributions are deducted before the tax is calculated then this will already have been taken into account in the box 1 figure.  
Thank you. 

Thank you @HMRC Admin 25 That was the exact answer i was hoping for. Perhaps you could amend your HICBC guidance to point people at the relevant box in theor self assessment or their P60 as the two figures match in my case as i only have one source of income. As for the Self Assessment, i suspect i dont need to do one but i dont mind submitting one as in the future i may need the flexibility. Every year there is a small charge to pay - less than £10 - which i can only assume it is a rounding error somewhere! Thanks a lot for your response - Wish i had re-started the child benefit earlier now as it looks like i may have been able to claim at least half of it in the previous tax year thanks to a Vehicle (EV) Salary Sacrifice scheme that reduced my reported figures significantly - by almost £10,000 in the box 1 of the SA102 for the Tax year to April 2024 Many thanks Michael