🏖️ Retirement Calculator
Find out if your savings are on track — and the nest egg you actually need.
How it works
This calculator answers two questions and then compares the answers. First: if you keep saving as you are, what will you have on the day you retire? That is your current savings plus your monthly deposits, compounded monthly at your expected return until your retirement age — the same maths as the investment calculator.
Second: how much do you actually need? That comes from the 4% rule. Research on US portfolios found that a retiree could withdraw about 4% of the starting pot in the first year, then increase the amount with inflation each year, and the money lasted roughly 30 years in most historical periods. Turned around, the pot you need is about 25 times one year of spending.
There is one wrinkle: your spending goal is in today's money, but you will spend it in future money. So the calculator first inflates your yearly spending to your retirement date, then divides by 0.04 to get the target. Finally it works backwards to the monthly saving that would land exactly on that target. Treat the target as a compass heading, not GPS coordinates.
An example
You are 30, retiring at 65, with $25,000 saved and $500 a month going in at a 7% average return. In 35 years that grows to $1,188,181.10 — a serious pot by any standard.
Now the other side. A spending goal of $4,000 a month in today's money becomes $135,065.40 a year by the time you are 65, after 35 years of 3% inflation. Divide by 0.04 and the target nest egg is $3,376,634.95. That leaves a shortfall of $2,188,453.85, and to close it on savings alone you would need to put away about $1,715.10 a month rather than $500. A gap like this is normal, not a verdict: retiring a few years later helps twice over — more years of growth, fewer years of spending — and any pension or Social Security income shrinks the target directly.
Common questions
Where does the 4% rule come from?
From studies of US investment history, starting with financial planner William Bengen's work in 1994 and the later Trinity study. They tested withdrawal rates against every 30-year retirement in the data, and 4% of the starting pot, rising with inflation, survived nearly all of them. Past survival is not a guarantee, which is why many planners now test 3.5% as well.
Does this include Social Security or a pension?
No, and that makes the target here larger than most people truly face. If you expect, say, $1,500 a month from Social Security, reduce your monthly spending goal by that amount before using the calculator — the income covers that slice of spending, so your savings only need to cover the rest.
What makes the biggest difference to the result?
Time, comfortably. Starting ten years earlier — or retiring a few years later — usually does more than squeezing out an extra percent of return, because compounding gets more years to work and the pot has fewer years to support. After time comes the saving rate itself; the return assumption matters least of the three.
Related calculators
This calculator gives estimates for learning. Rates, taxes and rules change, and your lender or the IRS has the final numbers — check big decisions against the real documents.