Retirement Calculator
Work out how much you need to retire — or how long your savings will last — based on your spending, investment return and inflation.
Planning the two big retirement questions
Retirement planning really comes down to two questions, and this calculator answers both. How much do I need? works out the nest egg required at the start of retirement to fund a chosen monthly lifestyle for a set number of years. How long will it last? takes the savings you already have and works out how many years they will cover your spending.
Both modes account for two forces that a simple ‘savings divided by spending’ sum misses: your money keeps earning a return while you draw it down, which makes it last longer, and your spending rises with inflation, which makes it run out sooner. The interplay between those two is what determines whether a pot lasts a decade or a lifetime.
The formula
The nest-egg figure is the present value of an inflation-adjusted income stream that earns your expected return while you spend it. In plain terms: the calculator grows your savings by the return each year, subtracts a year of spending, and lets that spending rise with inflation — repeating until the money is drawn down over your chosen period (or, in the second mode, until it runs out).
Worked example
Say you want $4,000 a month in today’s money for 25 years, expect a 5% return and 2.5% inflation. Because your savings keep earning 5% while you spend, you need far less than 25 × a year of spending — but because costs rise 2.5% a year, you need more than a no-inflation sum. Enter your own numbers above to see the exact nest egg, or switch modes to see how long a pot you already have would last.
When to use it
- Setting a concrete savings target for the retirement you want.
- Checking whether your current savings are on track to last.
- Stress-testing your plan against lower returns or higher inflation.
- Seeing the powerful effect that even a modest investment return has on longevity.
Assumptions & what’s not included
- It does not include any government pension or state benefits — add those separately.
- It assumes a steady return and inflation rate; real markets are lumpy.
- It keeps your spending power constant by raising withdrawals with inflation each year.
- It excludes tax and one-off large expenses — always confirm a real plan with a licensed adviser.
Frequently asked questions
How much do I need to retire?
A common rule of thumb is 25 times your annual spending, based on a 4% safe withdrawal rate. So if you spend $50,000 a year, you would aim for around $1.25 million. Your real number depends on your spending, investment returns, inflation and how long you need the money to last, which this calculator works out for you.
How long will my retirement savings last?
Switch to the 'How long will it last?' mode and enter your current savings and monthly spending. The calculator simulates drawing down your balance each year, while it keeps earning your chosen return and your withdrawals rise with inflation, and shows how many years the money covers.
Does the calculator include the pension?
No. It deliberately excludes any government pension or state benefits, so whatever you are entitled to is a bonus on top of the figures shown. It also excludes tax and market volatility, so treat the result as a simplified projection.
Why does investment return matter so much?
Your money does not stop working the day you retire. If your balance keeps earning a return while you draw it down, it lasts much longer, and you need far less up front. A pot earning 5 percent while you spend from it can last decades longer than the same pot earning nothing.
Is my data private?
Yes, completely. All calculations run in your browser. Nothing is sent to a server, stored, or shared, and there is no sign-up.