Savings Rate Calculator
Work out what share of your income you actually keep — and then the part that makes the number worth having: how many years that rate implies before your portfolio covers your spending, at a return and a withdrawal rate you choose.
Income and what you keep
Take-home or gross — either works, as long as your savings figure uses the same basis.
Everything you put away: cash savings, brokerage, retirement contributions, and any employer match.
The balance the horizon starts from. Enter 0 to see the from-scratch answer.
Saving 20% of income leaves $64,000.00 a year to live on, which is the figure the target is built from.
- Annual spending
- $64,000.00
- Target portfolio
- $1,600,000.00
- Years to reach it
- 34.3 years
| Savings rate | Saved per year | Years to target |
|---|---|---|
| 10% | $8,000.00 | 46.8 years |
| 20% | $16,000.00 | 34.3 years |
| 30% | $24,000.00 | 26.3 years |
| 40% | $32,000.00 | 20.4 years |
| 50% | $40,000.00 | 15.6 years |
| 60% | $48,000.00 | 11.6 years |
Raising the rate shortens the horizon twice over: it adds to the pile each year and lowers the pile you need, because the money you no longer spend is money the portfolio never has to replace. That second effect is why the rows fall away faster than the rate rises.
- Real return: 5% a year after inflation — your input, held constant every year.
- Withdrawal rate: 4%, so the target is 25 times annual spending.
- Starting balance: $40,000.00, with contributions added at the end of each year.
- Income, savings, and spending are held flat in real terms. No raises, no taxes on withdrawals, no pension or social security.
How the rate and the horizon are calculated
The rate itself is one division. The horizon is the same annuity equation every compounding calculator uses, solved for time instead of for a balance — so the answer comes out as a fractional number of years rather than being rounded up to the next whole one by a year-by-year loop.
Savings rate = Saved ÷ IncomeSpending = Income − SavedTarget = Spending ÷ Withdrawal rateYears = ln((Target + C∕r) ÷ (Balance + C∕r)) ÷ ln(1 + r)- C
- Amount saved each year, added at year end
- r
- Real annual return, after inflation
- Balance
- What you have invested today
- ln
- Natural logarithm
Two cases fall outside that formula and are handled separately. At a zero real return the equation divides by r, so the horizon reduces to plain division: the gap to the target over the amount saved each year. At a negative real return the balance converges to a ceiling rather than growing without limit, so any target above that ceiling is reported as unreachable instead of as a very large number of years.
$80,000 of income, $16,000 saved
Saving $16,000 out of $80,000 is a 20% savings rate, which leaves $64,000 a year to live on. At a 4% withdrawal rate the target is 25 times that spending, or $1,600,000. Starting from $40,000 already invested and compounding at a 5% real return, the horizon works out at 34.31 years.
Doubling the savings rate to 40% does far more than halve the wait. Saving $32,000 leaves $48,000 of spending, which drops the target to $1,200,000 — and reaching that smaller target with larger contributions takes 20.4 years. The rate doubled; the horizon fell by roughly 40%, because the target moved too.
For the same question framed around a retirement age rather than a rate, the FIRE calculator runs the projection from your current age.
What this calculator assumes
- Income, savings, and spending are flat in real terms for the whole horizon. No raises, no lifestyle drift, no career breaks.
- The return you enter is real — after inflation — and constant every year. Actual returns arrive in an order, and the order matters near the end of the horizon.
- Contributions are added at the end of each year. Contributing monthly instead shortens the horizon slightly.
- The withdrawal rate sets the target and nothing else. Taxes on withdrawals, investment fees, pensions, and social security are not modeled.
- Savings cannot exceed income here: a rate above 100% makes spending negative and the target meaningless.
- Horizons beyond 100 years are reported as unreachable rather than printed.
Savings rate FAQ
Should the savings rate use gross or take-home income?
Either, as long as both numbers use the same basis. A gross-income rate and a take-home rate for the same person differ by roughly the size of their tax bill, so they are not comparable to each other — which is why published savings-rate comparisons so often disagree. Pick one, note which you picked, and stay with it. Take-home is the more useful basis for a horizon calculation, because it is the money the spending figure is drawn from.
Do employer 401(k) contributions count?
Count them if they end up in your name, and make sure the income figure you divide by includes them too. An employer match is compensation you did not see on your payslip: adding $4,000 of match to savings while dividing by take-home pay that never contained it inflates the rate. Either add the match to both sides or leave it out of both.
Why does a higher savings rate shorten the timeline so sharply?
Because a change in the savings rate moves both halves of the problem at once. Saving more adds to the pile each year, and it also shrinks the pile you need — every dollar you stop spending is a dollar the portfolio never has to replace, and at a 4% withdrawal rate it removes twenty-five dollars from the target. That is why the comparison rows fall away far faster than the rate rises: going from 20% to 40% roughly doubles contributions but also cuts the target by a quarter.
Where does the 4% withdrawal rate come from?
It is a planning convention drawn from studies of historical US portfolio survival, most often traced to William Bengen's 1994 work and the later Trinity study. It says a portfolio withdrawing 4% of its starting value, adjusted for inflation, survived most historical 30-year retirements. It is not a guarantee, it is not a law, and it does not account for your fees, taxes, asset mix, or the specific sequence of returns you happen to get. It is editable here for exactly that reason — a 3% rate raises the target by a third, and seeing that is more useful than debating the number in the abstract.
Why does this ask for a real return instead of a nominal one?
Because the answer is a number of years, and years are only meaningful in constant purchasing power. If you enter a 8% nominal return while inflation runs at 3%, the calculator would reach a target expressed in today's dollars using tomorrow's money and report a horizon that is too short. Entering a real return — the nominal return minus inflation — keeps the target and the growth on the same footing.
Does paying down debt count as saving?
Paying principal on debt raises your net worth exactly as saving does, so it belongs in the savings figure if you are measuring progress. It does not build a portfolio that can be withdrawn from, though, so a horizon built mostly on debt payments will be optimistic about the date withdrawals can start. If most of what you save is debt principal, the honest reading is that the horizon effectively begins once the debt is cleared, and a debt payoff calculator is the tool that puts a date on that.
If debt is the thing standing between you and a higher rate, the debt payoff calculator puts a date on clearing it, and the 50/30/20 budget calculator shows what a target savings share looks like in dollars a month.
Sources and review notes
- U.S. Bureau of Economic Analysis — personal saving rate
- U.S. Securities and Exchange Commission, Investor.gov — compound interest
Methodology last checked Jul 28, 2026. Formula implementation is covered by deterministic unit tests, including the zero-return and negative-return cases. The 4% withdrawal convention is attributed in the FAQ above; it is not a figure this site endorses. No financial professional review is claimed yet.