UK withdrawal drawdown runway calculator

Enter your savings, premium bonds, cash and stocks and shares ISA values, and nominal growth/interest rate to work out how long it would last.

Notes

Ignores inflation and future changes in purchasing power — all figures are today’s £ money. Premium Bond “interest” is your chosen average prize rate and assume average luck, not a guaranteed return. The Stocks & Shares ISA uses a single constant nominal return, which real markets never deliver smoothly — treat it as a long-run average, not a forecast. Assumes constant rates, constant monthly expense, and a constant marginal tax rate on the savings pot. Not financial advice obviously.

Settlement allocation

Split your lump sum across pots below. Withdrawals are taken from the taxable savings pot first, then Premium Bonds, then the Cash ISA, then the Stocks & Shares ISA last (most tax-efficient / highest-growth wrapper preserved longest). Leave a pot at £0 to exclude it.

1. Savings account (taxable, drawn first)

Amount (£)

Annual rate (%)

Marginal tax rate on interest

2. Premium Bonds (tax-free, £50,000 limit, drawn second)

Amount (£, max 50,000)

Annual prize rate (%)

3. Cash ISA (tax-free, note allowance is £20,000/year, drawn third)

Amount (£)

Annual rate (%)

4. Stocks & Shares ISA (tax-free, no limit assumed here, drawn last)

Amount (£)

Nominal annual return (%)

Monthly expenses (£)