LuniBound · Free calculator
How much do I need to retire?
Pick the age you'd like work to become optional. See the nest egg you'd need, and how much you'd have to invest each month to get there.
| Retire at | Invest / month | Years away |
|---|
Same nest egg for every row; earlier retirement means fewer years to save it.
Estimates in today's dollars — see the assumptions below. Your inputs stay in this browser and are never transmitted.
The rule of 25
A common starting point is to multiply the yearly spending you want in retirement by 25. That comes from the "4% rule": historical studies of US stock and bond returns found that withdrawing 4% of a portfolio in the first year, then adjusting for inflation, usually lasted at least 30 years. 25 × spending is the same thing as spending ÷ 4%.
Retiring early usually means a retirement longer than 30 years, so many early retirees choose a lower withdrawal rate such as 3.5% — which raises the target to about 28.6 × spending. Try both in the calculator.
How the monthly amount is calculated
Monthly investing = (nest egg − today's money grown to retirement) × r ÷ ((1 + r)n − 1)
Here r is your monthly real return and n the number of months until you retire. Money you already have does part of the job, and the monthly amount fills the rest.
Example: age 35, $50,000 invested, $48,000 a year, 7% real return
The nest egg is $1,200,000. To retire at 65 you'd invest about $701 a month; at 55, about $1,983; at 50, about $3,414; and at 45, about $6,440. Each five years earlier costs much more than the last, because there are fewer years of saving and fewer years of compounding.
What this doesn't include
- Social Security and pensions. Any guaranteed income later in life reduces the portfolio you need. It isn't included here, which makes the estimate more conservative.
- Health insurance before 65. If you retire before Medicare eligibility, include private coverage in your yearly spending.
- Taxes, fees and market swings. This is a steady-return estimate. The full LuniBound planner shows the range of outcomes across 500 simulated market paths.
See your whole plan on one page
The LuniBound planner adds 500 simulated market futures, a growth chart, Coast FIRE and your moon progress — still 100% in your browser, with no account and no bank linking.
Open the full plannerQuestions
How much do I need to retire at 50?
Multiply your expected yearly spending by about 25 (a 4% withdrawal rate) — or closer to 28 if you want more margin for a long retirement. Spending $48,000 a year, that's roughly $1.2 to $1.37 million. The calculator shows how much to invest each month to get there from where you are.
What is the 4% rule?
A guideline from historical studies: withdrawing 4% of your portfolio in the first year of retirement and then adjusting for inflation has usually lasted at least 30 years. It's a starting point, not a guarantee.
Does this include Social Security?
No. Social Security or a pension would lower the portfolio you need. Leaving them out keeps the estimate on the conservative side.
Why does retiring a few years earlier cost so much more?
You lose saving years and compounding years at the same time, and your money has to last longer. That's why the monthly amount rises steeply as the retirement age falls.
Is my data private?
Yes. Everything is calculated in your browser and saved only in this browser's local storage. Nothing you enter is sent to Lunibyte or anyone else.