UK Savings Goal Calculator
How long to save £1 million, or how much per month to hit your target? Compare after-tax outcomes across an ISA, SIPP/pension (25% tax-free lump sum + 75% taxed), and a General Investment Account.
Spendable value after any withdrawal tax.
Basic 20%, higher 40%, additional 45%. Scotland: use your Scottish rate.
Tax-free growth and withdrawals — no income tax, no capital gains tax
Tax relief on contributions, tax-free growth, 25% tax-free lump sum on withdrawal
No tax advantages — dividends and capital gains taxed annually
Frequently asked questions
How long will it take to save £1 million?
At 7% annual return with no starting balance, you need around £520/month for 40 years, £875/month for 30 years, or £1,575/month for 25 years to reach £1 million in a tax-free ISA. In a SIPP the pre-tax balance must be higher (because 75% of withdrawal is taxed), and in a General Investment Account the horizon stretches due to annual tax drag on dividends and realised gains.
Why is the SIPP figure smaller than the ISA figure?
The calculator shows after-tax spendable value. A SIPP withdrawal is 25% tax-free lump sum + 75% taxed at your marginal rate — so £1M in a SIPP gives less than £1M in an ISA. The upside of a SIPP isn't the tax-free withdrawal (partially taxed), it's the 20-45% income tax relief on contributions, which isn't reflected in the shown monthly number.
What return should I use?
A diversified global equity portfolio has historically returned around 7-8% nominal per year over long horizons. A 60/40 stock/bond mix has been closer to 5-6%. If your goal is in today's money, use a real (after-inflation) return of 4-5%; if you're entering a nominal goal in future money, use 7-8%.
What marginal rate should I use?
For England/Wales/Northern Ireland: 20% basic (£12,571-£50,270), 40% higher (£50,271-£125,140), 45% additional (£125,140+). Scotland has different bands — use your applicable Scottish rate. The calculator applies this rate to annual GIA tax drag and to the taxable 75% of a SIPP withdrawal.
Are ISA and SIPP allowances reflected?
Not directly — this is a goal-seeking tool, not a contribution-planner. It assumes you stay within your annual allowances (ISA £20,000/yr, SIPP £60,000/yr subject to earnings/taper). Large monthly numbers may exceed one or both allowances; see the LISA Calculator, Pension Annual Allowance Calculator, and Salary Sacrifice Calculator for allowance-aware planning.