How is the personal pension payment for the coming tax year calculated?

Hello there, I paid approximately £3000 into my workplace pension in 2023/24 and I’m a higher-rate tax payer, so I claimed the extra 20% tax relief when I completed my self-assessment for 2023/24. My tax-free allowance for 2024/25 has now increased by £1450 to account for the personal pension payments I am likely to make in 2024/25. I’d like to know how HMRC predict how much I will contribute to my pension in 2024/25? Why do HMRC not assume I will make the same pension contribution as last year, and therefore increase my tax-free allowance by £3000? Any advice is greatly appreciated!

Hi Victoria Jones,
To confirm why our systems have calculated this update to your code, we would need to review your record.
To allow us to do this, contact us by webchat or phone here:
Self Assessment: general enquiries
Thank you.