How to use this savings rate calculator
- Enter your age, your take-home pay and either your yearly spending or the share of your pay you save.
- Enter what you have invested today, in retirement accounts and taxable accounts. Leave out your home.
- Check the return and withdrawal-rate assumptions, then read your years to financial independence, crossover point and risk tests.
What is a savings rate?
Your savings rate is the share of your take-home pay that you invest: savings rate = (take-home pay − spending) ÷ take-home pay. Someone who takes home $80,000 and spends $48,000 saves $32,000, a 40% savings rate.
The national figure is far lower. The US personal saving rate, saving as a share of after-tax income, was 3.8% in September 2026[2]. At that rate, starting from nothing, the savings-rate math says reaching financial independence would take 71.4 years under Mr. Money Mustache's assumptions and 86.6 years under ours: in practice, never without Social Security or a pension.
How many years to financial independence at my savings rate?
Your savings rate does two jobs at once. It sets how fast your investments grow, and it sets how much you need, because what you don't save is what you spend. Starting from nothing invested (our calculation):
| Savings rate | 5% real, 4% withdrawals | Our defaults, 4% | Our defaults, 3.5% |
|---|---|---|---|
| 5% | 65.8 | 79.2 | 82.6 |
| 10% | 51.3 | 60.6 | 63.9 |
| 15% | 42.8 | 49.8 | 52.9 |
| 20% | 36.7 | 42.1 | 45.0 |
| 30% | 28.0 | 31.4 | 33.9 |
| 40% | 21.6 | 23.8 | 25.9 |
| 50% | 16.6 | 17.9 | 19.7 |
| 60% | 12.4 | 13.2 | 14.6 |
| 65% | 10.5 | 11.1 | 12.3 |
| 70% | 8.8 | 9.2 | 10.2 |
| 80% | 5.6 | 5.7 | 6.4 |
Years of saving until investments cover spending, starting from zero. Our defaults are a 7% return, 3% inflation and 0.1% fees: a 3.79% real return.
The first column reproduces Mr. Money Mustache's 2012 table, "The Shockingly Simple Math Behind Early Retirement". The other two use this calculator's defaults. Every row tells the same story: the jump from 10% to 20% saves more working years than any later step of the same size.
Reproducing Mr. Money Mustache's table
The article's table rests on a few simple assumptions:
- investments earn 5% a year after inflation while you save;
- you retire on a 4% withdrawal rate, with some flexibility in bad years;
- you start from a net worth of zero;
- savings rate means the share of take-home pay (gross pay minus taxes, with 401(k) deductions added back);
- you keep spending the same amount after you retire.
Fed the same assumptions, our engine gives 51.3 years at a 10% savings rate and 16.6 years at 50%. The article quotes 51 years and about 16[1]. It also says that going from 10% to 15% lets a family retire about 8 years earlier; the engine gives 51 and 43 years in whole numbers, 8 years apart. Living on 35% of take-home pay (a 65% savings rate) gets you there in 10.5 years.
Why are our defaults more cautious?
Our default real return is 3.79%, lower than the table's 5%. It comes from a 7% nominal return, 3% inflation and 0.1% fees, combined with the Fisher equation: (1 + 7% − 0.1%) ÷ (1 + 3%) − 1. Two reasons for the gap:
- Forecasts are lower than history. US stocks returned 6.8% a year after inflation from 1928 to 2025[5], but Vanguard's 10-year forecast for US stocks is 4.8%-6.8% a year before inflation[6]. A plan that works at a lower return has room to spare if markets do better.
- Most portfolios hold some bonds, and 10-year Treasuries returned only 1.5% a year after inflation over the same period[5].
The withdrawal rate matters too. 4% was tested on 30-year retirements[7]. If you retire at 40 your money may need to last 50 years or more, and research on those horizons points to 3.25%-3.5%[8]. The last column of the table shows what 3.5% costs: at a 50% savings rate, 19.7 years instead of 17.9.
What is the crossover point?
The crossover point is the month your investment income first covers your monthly spending. The idea comes from Your Money or Your Life by Joe Dominguez and Vicki Robin, which the FIRE movement treats as a core text[4]. In the book's program you chart monthly investment income against monthly expenses; the point where the income line crosses above the expenses line is your crossover point, and from then on work is optional[3].
The original program counted interest from safe, fixed-income investments as investment income. Many FIRE portfolios today are mostly stock index funds, whose return comes largely from rising prices rather than payouts, so this calculator measures investment income as what your portfolio can safely pay out: monthly investment income = balance × withdrawal rate ÷ 12. With steady spending, that crosses your spending exactly when your balance reaches your FIRE number.
Crossover point example
Take the example from the top of the page: age 30, $80,000 take-home pay, $48,000 spending ($4,000 a month), $50,000 invested, a 4% withdrawal rate and our default 3.79% real return (our calculation):
- At 52, $1,182,442 invested pays $3,941 a month: not quite enough.
- At 53, $1,259,214 pays $4,197 a month, more than the $4,000 spent.
- The lines cross 22 years and 3 months from now, when the balance reaches the FIRE number of $1,200,000.
The calculator's chart draws these two lines for you. Our FIRE calculator counts in whole years, so for the same inputs it shows financial independence at 53, the first birthday after the crossover.
A second milestone: when growth beats savings
Long before the crossover, there is a quieter turning point: the year your investments are expected to grow by more than you add. In the example that happens at 48, when a balance of $902,359 is expected to grow about $34,167 in a year against $32,000 of new savings. From there, compounding does more of the work than your paycheck. The retirement compound interest calculator shows that effect in detail.
How early can I retire?
How early you can retire depends mostly on your savings rate, not your income. Here is the age you would reach financial independence if you started investing at 25 with nothing saved, using our default return (our calculation):
| Savings rate | FI age at 4% | FI age at 3.5% |
|---|---|---|
| 15% | 75 | 78 |
| 25% | 62 | 64 |
| 35% | 53 | 55 |
| 50% | 43 | 45 |
| 65% | 37 | 38 |
| 75% | 33 | 34 |
FI age is the first birthday after the crossover point.
Income still matters in practice: a higher income makes a high savings rate easier, and taxes, health insurance and Social Security change the picture. But the math itself scales. At a 30% savings rate the years to financial independence are the same, 31.4, whether you take home $50,000 or $200,000, because the person on $200,000 also needs a portfolio four times larger.
Should I spend less or earn more?
Both raise your savings rate, but spending less works twice: you invest the money, and you need a smaller portfolio to replace it. Take the example above, 22.2 years from financial independence, and find an extra $6,000 a year (our calculation):
- Spend $6,000 less: 18.0 years to FI, because the FIRE number also drops by $150,000.
- Earn $6,000 more and invest all of it: 19.9 years to FI. The FIRE number stays at $1,200,000.
There is a floor on how far spending can fall, so earning more still matters: a raise you invest is worth 2.4 years. The point is to protect raises from lifestyle creep: if spending rises with every raise, your savings rate never moves, and neither does your date. The what-if table in the calculator runs these trade-offs on your own numbers.
What is a FIRE age?
Your FIRE age is the age at which your investments can pay for your life, so paid work becomes optional. It is your current age plus your years to financial independence. In the example above, the FIRE age is 53. Whether you actually retire then is a separate choice: many people keep working part time, which is the idea behind Barista FIRE, or stop saving early and let compounding finish the job, which is Coast FIRE.
Does what I have saved already change the answer?
Yes, and the table above assumes you start from zero. What you have invested counts most when it is large compared with your pay. At a 40% savings rate, with our default return (our calculation):
| Invested today | Years to FI |
|---|---|
| Nothing | 23.8 |
| 0.5 years of take-home pay | 22.5 |
| 1 year of take-home pay | 21.3 |
| 2 years of take-home pay | 19.1 |
| 5 years of take-home pay | 13.3 |
What the savings-rate math leaves out
- Market swings. The years above assume a steady return. A crash just after you stop working does more damage than the same crash later[9], which is why the calculator runs 2,000 Monte Carlo simulations and replays every start year since 1928.
- Social Security and pensions. They lower what your portfolio must pay later in life. The FIRE calculator includes them.
- Changes in spending. Health insurance before Medicare, taxes on withdrawals, children and housing all shift your number. Revisit the plan as your life changes.
- Raises. If your pay rises and your spending doesn't, your savings rate climbs and the date moves closer. Recalculate after each raise.