FinToolSuite

Portfolio Drawdown Calculator

Updated April 17, 2026 · Savings · Educational use only ·

How long savings last at a given spend rate.

Calculate how long a portfolio will last at a specified annual withdrawal rate and expected return. Enter portfolio value to see years the portfolio sustains.

What this tool does

Enter portfolio, annual withdrawal, and expected return. The tool shows years the portfolio sustains.


Enter Values

Formula Used
Portfolio
Annual withdrawal
Annual return

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Disclaimer

Results are estimates for educational purposes only. They do not constitute financial advice. Consult a qualified professional before making financial decisions.

500,000 portfolio with 30,000/year withdrawal at 5% return lasts 37 years. At 6% return, it can last indefinitely. At 4% return, about 23 years. The gap between 4% and 6% is decades — return assumptions matter enormously for retirement sustainability.

Quick example

With portfolio value of 500,000 and annual withdrawal of 30,000 (plus expected return of 5%), the result is 37.0 years. Change any figure and watch the output shift — it's often more useful to see the pattern than to memorise the formula.

Which inputs matter most

You enter Portfolio Value, Annual Withdrawal, and Expected Return. Not every input has equal weight. Flip one at a time toward extreme values to feel which ones move the needle most for your situation.

What's happening under the hood

Solve for n when portfolio equals zero after n annual withdrawals compounding at return rate. Annual compounding, withdrawals at year end. The formula is listed in full below. If the number looks off, you can retrace the calculation by hand — that's the point of showing the working.

How to use this beyond the first run

Re-run the calculation once a year. Life changes — pay rises, new expenses, interest-rate shifts — and the figure that looked right 12 months ago often isn't today. Annual recalibration keeps the plan honest.

What this doesn't capture

The calculation assumes a steady savings rate and a stable interest rate. Real saving journeys include emergencies, windfalls, and rate changes — especially in easy-access products. The figure is a direction of travel, not a guarantee.

Where to go next

This calculation rarely sits alone in a planning exercise. If you're running these numbers, you'll probably also want the safe withdrawal rate calculator, the maximum savings rate calculator, and the pension drawdown sustainability calculator — each one answers a different question in the same territory. Treating them as a set rather than in isolation usually produces a more honest picture.

Example Scenario

Drawdown produces a year count based on the inputs provided.

Inputs

Portfolio Value:500,000 £
Annual Withdrawal:30,000 £
Expected Return:5
Expected Result37.0 years

This example uses typical values for illustration. Adjust the inputs above to match a specific situation and see how the result changes.

Sources & Methodology

Methodology

Solve for n when portfolio equals zero after n annual withdrawals compounding at return rate. Annual compounding, withdrawals at year end.

Frequently Asked Questions

Is this the 4% rule?
Related. The 4% rule uses historical return sequences; this calculator uses a single constant return. Both are approximations — real retirement has return variance.
Return assumption sensitivity?
Huge. 1% return change can add or subtract years from sustainability. Use conservative assumptions when planning.
Sequence of returns risk?
Early losses in retirement are far more damaging than later losses. This constant-return tool doesn't capture that — treat output as best case.
What if withdrawal is flexible?
Cutting withdrawals in down markets extends portfolio life significantly. Rigid withdrawal plans are highest risk; flexible plans are more sustainable.

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