Savings rate to
financial independence.

This tool runs entirely in your browser: no data is sent to any server. It uses only the numbers you enter, which this browser's local storage keeps for the next visit:

• Annual spending = the expenses you enter, used as entered. Annual savings = take-home pay − expenses. Savings rate = savings ÷ take-home pay, shown to at most one decimal place (n/a when pay is $0). A negative pay or expense entry counts as $0, and the result says so. A blank field counts as 0, and the result names it. A negative current savings figure is used as entered, as a shortfall that compounds at the real return.
• Moving the slider (0% to 80%), with pay above $0, sets expenses = take-home pay × (1 − rate), rounded to the dollar, and the math reruns from there. A rate above 80% or below 0% from your own numbers is used in full; the slider just rests at its 0% or 80% end. If expenses exceed pay, savings are negative and come out of the portfolio each year.
• FI number = annual spending ÷ withdrawal rate. At 4%, that is 25 × spending.
• Years to FI = the first n, tested in half-year steps up to 100 years, where current savings × (1 + r)ⁿ + annual savings × ((1 + r)ⁿ − 1) ÷ r reaches the FI number, with r the real return, which may be negative (at exactly 0%, current savings + annual savings × n). This is the year-end deposit formula, also evaluated at the half-year points. The result shows as Now when already there, in months when under a year, otherwise in whole years (half years round up), and as ∞ when not reached within 100 years; the FI year = this year + n, rounded up. With a negative return the portfolio can level off below the FI number, and the result is then ∞. A withdrawal rate of 0% or less (a blank one counts as 0), or a return of −100% or less, makes Years to FI show ∞ and the page asks for a valid entry.
• The what-if slider and the 10% to 70% table rerun the same math at other savings rates, with expenses = take-home pay × (1 − that rate), worked in whole percents so 70% of $100,000 is exactly $70,000. A result that lands exactly on the FI number counts as reached. The what-if gap is the difference between the two figures as shown (6 months against 3 years reads as 2 years and 6 months). The table highlights the rows within 5 points of your savings rate, measured on the unrounded rate.

The 5% real return and 4% withdrawal rate are editable defaults, not sourced forecasts. Not modeled: taxes, raises, market swings, and spending that changes after FI. Verify the methodology or inspect the source code in your browser's dev tools.