Savings Withdrawal Calculator
Find out how long your savings will last with a regular withdrawal, or how much you can withdraw each month to make your pot last a set number of years.
Reviewed by Richard Ross · Last updated April 2026
How Savings Withdrawal Calculator works
How long savings last
With interest: months = −ln(1 − r × PV ÷ PMT) ÷ ln(1 + r), where r is the monthly rate, PV is starting balance, and PMT is monthly withdrawal. Without interest: months = balance ÷ withdrawal.
Maximum sustainable withdrawal
PMT = PV × r ÷ [1 − (1 + r)^(−n)], the standard annuity payment formula. This gives the level monthly withdrawal that exhausts the balance (including interest) exactly at the target date.
Inflation and real returns
This calculator uses nominal rates. In reality, inflation erodes purchasing power. To maintain real (inflation-adjusted) withdrawals, reduce the stated interest rate by the expected inflation rate (e.g., 4% nominal − 2.5% inflation = 1.5% real rate).
UK tax considerations on savings withdrawals
Withdrawals from a standard savings account are not themselves taxable — only the interest earned is taxable. However, for drawdown from a pension, different rules apply: 25% of the pot can be taken tax-free (Pension Commencement Lump Sum), with the remaining 75% taxed as income. For ISA withdrawals, there is no tax at any stage. If you are drawing down savings to supplement retirement income, planning which pot to draw from first (ISA before pension, or vice versa) can significantly reduce your overall tax bill.
Safe withdrawal rates and the 4% rule
A widely cited benchmark in retirement planning is the "4% rule" — withdrawing 4% of your portfolio in year one, then adjusting for inflation annually. Research (originally based on US data) suggests this sustains a 30-year retirement with a diversified portfolio. For UK savers using cash savings only (rather than a mixed portfolio), a lower withdrawal rate is typically needed because cash returns are lower and less inflation-resistant over the long term. This calculator helps model the exact duration and withdrawal amount for your specific balance and rate.
Source: MoneyHelper — Retirement income planning (moneyhelper.org.uk). GOV.UK — State pension rates (gov.uk/state-pension). Bank of England — savings and interest rate data (bankofengland.co.uk).
Frequently asked questions
How long will £100,000 last with £1,000 monthly withdrawals?
At 4% annual interest (compounded monthly): approximately 11.5 years. At 0% interest: exactly 100 months (8.3 years). At 5% annual interest: approximately 14 years.
How much can I withdraw monthly from £200,000 to last 20 years?
At 4% annual interest: approximately £1,212/month. At 0% interest: £833/month. At 5% annual interest: £1,320/month.
What happens if my withdrawal rate exceeds the interest earned?
Your balance declines over time. How long it lasts depends on the shortfall between interest earned and withdrawals. This calculator shows the exact duration.
Should I use this for retirement planning?
This is a simplified estimate. Retirement planning should also account for state pension, inflation, tax on withdrawals, annuities, and healthcare costs. Speak to a regulated financial adviser for personalised retirement planning.
What is the full new State Pension and how does it affect my savings drawdown plan?
The full new State Pension is £221.20 per week (2025–26), or approximately £957 per month. If you qualify, this reduces the amount you need to draw from your savings each month. For example, if your monthly expenses are £2,000 and you receive £957 in State Pension, you only need to withdraw £1,043 from savings — significantly extending how long your pot lasts. You can check your State Pension forecast at gov.uk/check-state-pension.
Is it better to keep savings in an ISA during drawdown?
Yes — withdrawals from an ISA are completely tax-free, and there is no requirement to report them to HMRC. Keeping savings in a Cash ISA during drawdown means all interest earned while you draw down is also tax-free. This is particularly valuable in retirement if other income (pension, State Pension) has already used your Personal Allowance, making any further taxable interest subject to 20%+ tax.
How do I minimise tax on savings withdrawals?
Savings interest is taxable above your Personal Savings Allowance (£1,000 for basic-rate, £500 for higher-rate taxpayers). To minimise tax: use ISAs for sheltered interest; spread savings across a partner's account if they have unused allowance; choose assets that produce capital gains (taxed at 18%/24%) rather than income where possible for non-ISA investments; and time large interest-generating bonds to mature in years when your income (and thus tax rate) is lower.
What is the 4% safe withdrawal rate?
The 4% rule (developed from US market data in the 1990s) suggests that withdrawing 4% of your initial portfolio annually, adjusted for inflation, has historically lasted 30+ years in most scenarios. For a £300,000 portfolio: 4% = £12,000/year. However, the rule was developed using US equities and bonds — UK and global equivalents suggest a more conservative 3.5% for UK retirees. The calculator lets you test different withdrawal rates against your balance.
At what point will my savings run out?
This depends on three factors: starting balance, annual withdrawal, and net return after charges and inflation. The calculator models this precisely. As a rough guide, at 0% real return, £200,000 lasts 20 years if you withdraw £10,000/year. At 3% real return, the same pot lasts approximately 27 years. At 5%, it lasts indefinitely (4% withdrawal from 5% return leaves 1% for growth). Increasing returns or reducing withdrawals by even small amounts significantly extends longevity.
Should I draw down savings or pension first in retirement?
This depends on your tax position. In the early years of retirement before State Pension age, drawing from ISAs and taxable savings first, while allowing your pension to grow, can be tax-efficient. Pension income is taxable above the personal allowance, whereas ISA withdrawals are always tax-free. However, from April 2027, unspent pension pots will be subject to IHT — which may change the optimal drawdown order for estate planning. A financial adviser can model the optimal sequence for your circumstances.