Retirement Planning Simulator

The calculator moves forward one month at a time. Each month, every account grows a little (based on the yearly rate you set), then your deposits or withdrawals are applied. It's the same way interest actually builds up — not a rough estimate.

No. The simulator runs entirely inside your local web browser using JavaScript. Your inputs are never transmitted, making it 100% private.

Choose "Total spending," enter an amount and how often you expect to spend it, and the calculator takes that amount from your accounts on that schedule while the rest keeps growing. The message under the big number shows the year and month planned spending could no longer be met in full under your assumptions — or confirms it stays covered for more than 100 years.

It's built with the American retirement system in mind — 401(k)s, Roth IRAs, and similar accounts. But the underlying math (saving, growth, and spending) is universal. If you live elsewhere, just rename the accounts to match your own (a pension, an ISA, an RRSP, a superannuation fund), pick your currency at the top of the Plan settings card, and enter amounts in it. Only remember that tax rules differ by country.

Each account has a growth rate and a separate dividend yield, for both the saving and retirement phases. Growth is price appreciation only — the dividend is added on top. So a $500,000 account with 4% dividends earns about $20,000 in dividends the first year, plus whatever price growth you set. While you're saving, dividends are reinvested and compound alongside price growth. In retirement, if you use the “Total spending” plan, dividends are collected as cash and spent first — income you get without selling investments — and only the shortfall is covered by selling principal; any dividends you don't spend stay invested and keep compounding. The results show exactly how much of your spending came from dividends versus sold principal. Tip: if the return figure you have in mind already includes dividends (many fund “total return” numbers do), set the dividend yield to 0 to avoid counting them twice.

No. The "Tax Treatment" label on each account is a reminder of what kind of account it is — it does not deduct any taxes from the projections. Taxes vary enormously by person, income, and location, so the numbers you see are before tax. A financial professional can help you estimate the after-tax picture.

Three ways. Your plan saves automatically in your own browser, so it’s there when you come back on the same device. The web address also updates as you type — copy it to share your exact scenario or open it on another device. Your figures live in the part of the link after the #, which your browser never sends to any server or analytics — but the link does contain your plan assumptions in encoded form, so share it only with people you’re comfortable seeing those numbers. And the “Print / Save PDF” button opens your browser’s print window, where “Save as PDF” creates a clean report of your results.

This is exactly what the calculator is built for. Set the retirement length to your life expectancy or beyond — many planners suggest planning to age 90 or 95 to be safe. Then look at the verdict under the big number: it tells you the exact year and month the money would run out. If it comes up short, adjust your spending, your withdrawals, or your savings until the verdict turns green. A few minutes of experimenting shows you precisely which lever matters most for your situation.

Yes — they have their own section, because they work differently from savings: Social Security and pensions pay you for life and can’t run out. In the Guaranteed monthly income card, enter up to three sources (Social Security, a pension, and an annuity or other income) and mark whether each rises with inflation. Social Security gets cost-of-living adjustments; many private pensions stay fixed — and a fixed pension quietly covers less and less as prices rise. A dedicated chart shows what you’ll receive each month through retirement and what it’s really worth in today’s money. In the “Total spending” plan, this income is spent first and your accounts only cover the remainder.

The main projection assumes your accounts earn the same return every year — real markets never do that. The Monte Carlo chart, shown below the main projection, replays your exact plan through 1,000 randomized market futures, month by month, using each account's “Ups & downs (volatility)” setting. You'll see the typical (median) path, one example future, and a shaded band from unlucky (10th percentile) to lucky (90th) outcomes — plus the percentage of futures in which all planned spending was covered for the whole plan (a plan fully funded by guaranteed income counts as covered, even at a $0 balance). As a starting point, broad stock funds have historically swung around 15–18% a year, bond funds around 4–6%, and cash close to 0%. The randomness is calibrated so the typical (median) path lines up closely with the steady-returns projection — the two views tell one consistent story, and with volatility at 0 they match exactly.

Prices rise over time, so money in the future buys less than the same amount today. Your results always show future amounts. When you switch inflation on, the calculator adds a second line under the big numbers — "≈ worth X in today's money" — so you can see both the future total and what it would actually feel like. The chart also draws a dashed line tracing your balance in today’s money, so you can watch inflation’s gradual pull over the whole journey. And if you use the "Total spending" plan, your spending amount automatically rises with inflation so its buying power stays constant through retirement.