Junior SIPP calculator
Compare paying into a child’s pension until different ages, then leaving the pot invested. See the contributions, assumed tax relief and modelled growth separately.
2026/27 · £100 paid in becomes £125 with eligible basic tax relief.
What could it grow to by age 60?
£100 a month becomes £125 with basic tax relief. Compare two payment timelines below.
Stop at age 10
£69,569
About £17,890 in today’s money
Keep paying until 18
£154,300
About £39,678 in today’s money
Illustration before withdrawal tax: 5% growth, 0.75% fees and 2.5% inflation. Future returns and pension-access rules can change.
Make it your scenario
Existing savings and growth assumptions
Your payments, tax relief and growth
Stop at age 10
- Your new payments
- £6,000
- Basic tax relief added
- £1,500
- Growth or loss after fees
- £62,069
Keep paying until 18
- Your new payments
- £15,600
- Basic tax relief added
- £3,900
- Growth or loss after fees
- £134,800
Year-by-year pot values
| Age | Pot |
|---|---|
| 5 | £0 |
| 6 | £1,530 |
| 7 | £3,125 |
| 8 | £4,790 |
| 9 | £6,528 |
| 10 | £8,340 |
| 11 | £8,702 |
| 12 | £9,079 |
| 13 | £9,472 |
| 14 | £9,883 |
| 15 | £10,311 |
| 16 | £10,758 |
| 17 | £11,224 |
| 18 | £11,710 |
| 19 | £12,218 |
| 20 | £12,747 |
| 21 | £13,300 |
| 22 | £13,876 |
| 23 | £14,477 |
| 24 | £15,105 |
| 25 | £15,760 |
| 26 | £16,443 |
| 27 | £17,155 |
| 28 | £17,899 |
| 29 | £18,674 |
| 30 | £19,484 |
| 31 | £20,328 |
| 32 | £21,209 |
| 33 | £22,128 |
| 34 | £23,087 |
| 35 | £24,088 |
| 36 | £25,131 |
| 37 | £26,221 |
| 38 | £27,357 |
| 39 | £28,542 |
| 40 | £29,779 |
| 41 | £31,070 |
| 42 | £32,417 |
| 43 | £33,821 |
| 44 | £35,287 |
| 45 | £36,816 |
| 46 | £38,412 |
| 47 | £40,077 |
| 48 | £41,813 |
| 49 | £43,626 |
| 50 | £45,516 |
| 51 | £47,489 |
| 52 | £49,547 |
| 53 | £51,694 |
| 54 | £53,934 |
| 55 | £56,272 |
| 56 | £58,710 |
| 57 | £61,255 |
| 58 | £63,909 |
| 59 | £66,679 |
| 60 | £69,569 |
Calculation method
Payments go in at month-end for whole years, then the pot stays invested. Monthly growth is the yearly return less percentage fees, divided by 12. Tax relief uses the current eligible no-earnings basis throughout. Other contributions can reduce the amount eligible for relief. Flat fees, dealing charges and withdrawal tax are excluded.
2026/27 basis, sources checked 12 September 2026. This tool assumes eligibility for the current no-earnings relief-at-source basis: up to £2,880 paid in becomes £3,600 including basic relief. The monthly limit assumes no other contributions use that capacity. See HMRC’s rules.
How to use the comparison
Use the two timelines to explore how contributions and time affect the pot. Money in a pension stays restricted until the applicable access age; see the current pension-age rules. Investment values can fall, and a long horizon does not guarantee a gain.