Incorrect SIPP contribution

Hi, for 23-24 I wanted to put all of my earnings into my SIPP. The numbers are made up for simplicity. Earned Income: 20,000 say I paid 5000 at 40% tax rate for the year across earnings and pension. Tax at 20% (BR) 15000 *0.2 = 3000 Tax at 40% 5000 * 0.4 = 2000 Total = 5000. So I think the following is correct, Add 15000 and get 20% RAS of 3750 = 18750 Claim 1250 using self assessment. Total in SIPP = 18750 + 1250 = 20000 Added 15000 Tax back = 3750 + 1250 = 5000 However, I've just taken 20000*0.8 = 16000 and got 4000 RAS. I added 16000 instead of 15000 and missed out on the 40% additional through a tax return. Can I correct this? Can I still claim the 1250 and use the extra 1000 I paid in against 24-25 Income. Or is there nothing I can do now? Many Thanks

Hi D629597,
We cannot comment on scenarios, real or imagined.  You can pay up to £60000 or up to your earning level if lower than this.  Your pension provider would claim 20% tax relief from HMRC.  You gross up your payment into your pension ((payment/80)*100).  You then claim a further 20% from HMRC by either declaring in a self assessment tax return or by writing to HMRC at H.M. Revenue and Customs Pay As You Earn BX9 1AS, including supporting evidence of payments made.  This can be provided by your pension provider.
Thank you.