Is the tax paid by my employer being refunded to me?

Hi, I was registered as self employed in the year 2023/2024 but also started a full time job in January 2024. My income from self employment for that tax year is less than £6k and I opted out of voluntarily paying Class 2 NIC so the form said that I owe £0, just as I expected. However, just before I completed my self assessment form I got this message ''Total tax repayable to you: xxx.xx (the exact number that my employer has paid towards my tax between January and April of 2024).''. My self employment earnings and the earnings for these 3 months of the tax year during which I've been in full time employment are less than the tax-free Personal Allowance of £12,570 but I'm not sure if HMRC is trying to give me back the tax that my employer has paid and if so, why? What should I do in these circumstances? Will my employer find out if I had gotten a refund? Is there a way to not get a refund? And lastly, if I was to get a refund, my earnings would be above £6k which means that I now owe NI. What should I do?

Hi Tina,
If your overall income, including the income from your Self Employment and your full-time PAYE employment, is less than £12,570, then any tax paid via your full-time employment should be refunded to you.
This refund would not count as Self Employment income, so no additional Class 2 NIC would be due.
If you would like us to check your record and confirm this for you, contact us by webchat or phone here:
Self Assessment: general enquiries
Thank you. 

Here is a possible reason why what you have mentioned could have happened: When you started employment in January, you may have been given a PAYE tax code which instructed your employer to calculate your tax free amount only based on the months they were actually paying you. If so, now you are filling in Self Assessment, it is looking back over the entire year, and finding you have unused Personal Allowance within the whole year which can be set against your employment earnings - meaning you would have paid more tax than is due, and can get it back.