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Decision ToolA SIPP gives you tax relief going in. An ISA gives you tax-free money coming out. Which produces a better net result at retirement depends on your current tax band vs expected retirement band. This calculator does the maths with your inputs.
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The core identity: SIPP vs ISA is a comparison between today's tax rate and retirement tax rate. If equal, they produce identical net results. If retirement is lower, SIPP wins. If retirement is higher, ISA wins.
SIPP also benefits from the 25% tax-free lump sum (first 25% of pension taken tax-free). This gives SIPP an edge in equal-band scenarios too.
SIPP for retirement bulk, ISA for flexibility. Many UK investors contribute enough to a SIPP to capture full employer match and higher-rate relief, then route additional savings to a Stocks & Shares ISA.
No. Minimum pension age is 55 now, rising to 57 in 2028. ISAs have no age restriction.
LISA is a hybrid — government bonus (like SIPP relief) but tax-free withdrawal (like ISA). Great for under-40s saving for a first home or retirement.
Factored into this calculation. 25% of the SIPP pot is tax-free at retirement; the rest is taxed at your retirement band.
Projections assume a fixed annual return — real markets do not return the same figure every year. Capital at risk. Past performance does not guarantee future results. General information only, not personalised financial advice.