You’re able to pay as much as you like into a SIPP in any given year, but should remember that there are restrictions on the tax relief that you’re eligible to receive. So in the current 2021/22 tax year, if you’re a UK taxpayer, you can get relief on contributions to the lower of either 100% of your annual earnings or a predetermined £40,000 annual allowance. Anything you put into your pension beyond this won’t receive pension tax relief, while there’s a lifetime allowance, which currently stands at £1,073,100, to be aware of too - exceed this and a tax penalty is coming your way.
If you’re a non-taxpayer, because you have no or too little earnings, you can still make contributions into a SIPP and qualify for tax relief at 20% on payments of up to £2,880 each tax year. With the relief, your pension will be receiving an overall contribution of £3,600 a year.
If you have more than one pension that you pay into, it’s important to note that the pension tax relief limits apply to individuals, rather than individual pension schemes.