Junior SIPP Calculator

Use our free and easy junior SIPP calculator to see how much their pension pot would be worth when they turn 18 and when they retire.

Selected Value: 5 %
Selected Value: 18 years

How to use our Junior SIPP Calculator:

The calculator is a tool to help you estimate what a child’s Junior SIPP might be worth in the future, based on how much is contributed, over how long, and at what assumed annual return.

It shows:

  • Final SIPP value at the end of the projected period
  • Total contributions made
  • Total returns (i.e. growth above contributions)

You can use it to run “what if” scenarios (e.g. what if I increase the monthly contribution, or assume a higher return) to see the impact.

Here are the fields you need to fill in (or adjust) to run the junior SIPP calculation:

Section What it that? Tips
Initial Junior SIPP Contribution A one-off lump sum at the start If you make an initial deposit, put it here. If none, enter zero.
Expected Annual Returns The assumed average rate of investment growth per year The default is 5 %. You can increase or decrease this to see how more optimistic or pessimistic return assumptions affect the result. Good Money Guide+1
Monthly Junior SIPP Contribution The amount you plan to regularly add each month This is in addition to the initial contribution.
Years Invested The number of years over which contributions and growth are assumed For example, if the child is newborn and you plan until 18, put 18 years. The calculator lets you see the value at 18. Good Money Guide+1

Once these inputs are set, the JSIPP calculator outputs:

  • Final SIPP Value (i.e. projected pot size)
  • Total SIPP Contributions (sum of all lump sums + monthly contributions)
  • Total SIPP Returns (final value minus contributions)

Keep this in mind too

The calculator does not account for fees (platform fees, fund charges, trading costs, etc.). You can compare the cheapest Junior SIPP accounts here.

  • It’s a projection, not a guarantee. Assumed returns may or may not materialise in reality.
  • Because the money is locked until a future date (currently age 55, rising to 57 in 2028) for a SIPP, you should think long term.
  • The calculator is good for comparing scenarios (e.g. “what if I invest £100 vs £200 per month?”) rather than precise forecasting.
  • Remember, contributions to a Junior SIPP are eligible for 20% tax relief (i.e. the government tops up your contribution) up to the annual allowance of £2,880.

Also note: anyone (parents, grandparents, etc.) can contribute to the Junior SIPP, subject to the annual limit across all contributions.
At age 18, the Junior SIPP becomes a normal SIPP, and control is passed to the child.

Ready to start investing for your children’s pension?

Compare the best junior SIPP accounts to help get your children investing for their pension early. Good Money Guide has tested, ranked and reviewed the best Junior SIPP account providers in the UK that are regulated by the FCA.
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