Quick answer
Monthly savings equals income minus expenses. At $5,500 income and $4,200 expenses you save $1,300 per month. A $100,000 goal takes about 77 months (six and a half years) with no investment growth. Turn on expected return to model compound growth. Enter your numbers above and pick a target or type your own.
How to use this calculator
- Pick your currency. It defaults to US dollars.
- Enter monthly income and monthly expenses. Be honest on expenses; the timeline only works if the gap is real.
- Set a savings target using a preset button or a custom amount.
- Optional: enter an expected annual return percent to model invested savings (default off matches flat saving).
- Read months to goal, years and months, savings rate, and the growth chart when returns are on.
The formula, with worked examples
Flat saving (no return). Months to goal = target / monthly savings. If monthly savings is zero or negative, the goal is not reachable until income exceeds expenses.
With compound growth. Each month adds your savings plus return on the balance. We compound monthly at annual return divided by 12. The math is a future value of a payment series. Returns are not guaranteed; the toggle is for planning, not prediction.
Example: $5,500 income, $4,200 expenses, $100,000 target. Monthly savings is $1,300. Flat timeline: 100,000 / 1,300 = 76.9, so 77 months. At 7 percent annual return compounded monthly, the same path lands near 66 months because early balances earn growth while you keep contributing.
Your FIRE number in one paragraph. A common planning shortcut is 25 times annual expenses (the inverse of the 4 percent withdrawal rule). If you spend $50,000 per year, the rough independence target is $1.25 million. The 4 percent rule says you might withdraw 4 percent of the portfolio in year one and adjust for inflation, based on historical US stock and bond mixes. It is a heuristic, not a promise. Sequence of returns, taxes, and healthcare can break the model.
Months to save (flat saving, no investment return)
| Target | $500/mo | $1,000/mo | $2,000/mo |
|---|---|---|---|
| $50,000 | 100 mo | 50 mo | 25 mo |
| $100,000 | 200 mo | 100 mo | 50 mo |
| $250,000 | 500 mo | 250 mo | 125 mo |
Rounded up to whole months. Add expected return in the tool to shorten these timelines.
Frequently asked questions
What is financial freedom in numbers?
For many planners it means invested assets cover annual spending without a paycheck. The quick math is 25 times yearly expenses (based on the 4 percent withdrawal rule). Someone spending $40,000 per year might target roughly $1 million invested. Your number depends on lifestyle, location, and debt.
What is the 4 percent rule?
Retirees might withdraw 4 percent of the portfolio in the first year and adjust for inflation afterward. Historical US data supported this for 30-year retirements in many simulations. Low-yield periods and long retirements may need 3 to 3.5 percent instead. It is a starting point, not a law.
How much of my income should I save?
Fifty thirty twenty is a common split: 50 percent needs, 30 percent wants, 20 percent savings and debt payoff. Many FIRE-minded households push savings to 30 to 50 percent by cutting wants or raising income. The right number is the one you can sustain for years.
What is a realistic return assumption?
Long-run US stock returns near 7 percent after inflation show up in many planning models, but decades vary wildly. Use a conservative rate (4 to 6 percent) for planning and treat higher figures as optimistic. The SEC's compound interest calculator at investor.gov is a neutral place to experiment.
Should I pay off debt or save first?
High-interest debt (credit cards, payday loans) usually comes before investing beyond an employer match. Low-rate mortgage debt is a judgment call: guaranteed return from payoff versus market returns and liquidity. Build a small emergency fund either way so one bill does not undo the plan.
What is Coast FIRE?
Coast FIRE means you have invested enough that compound growth alone could reach your retirement number by a target age, even if you stop new contributions. You still need income for today's bills, but you no longer need to save aggressively for the far future.
Formula and sources
Formula: Flat: months = target / monthly savings. Compound: monthly FV of contributions plus growth on balance at (annual return / 12).
Sources:
This is an educational estimate, not financial advice. Read our disclaimer.
Written by Raja Jahangir. Reviewed by Armghana Zeeshan. Last updated: June 30, 2026.