Savings Rate Calculator

Savings rate is the fraction of income not consumed. This calculator computes it two ways: against gross income, and against net income after the taxes you enter, using retirement contributions plus other savings as the numerator. The reason practitioners favor this metric over dollar amounts is that it is scale-free and it moves two variables at once. Raising the rate increases annual contributions while simultaneously lowering annual spending, which lowers the target portfolio itself. That target is estimated here as 25 times annual expenses, the inverse of the 4 percent withdrawal rule, and the years-to-target figure inverts the future-value-of-an-annuity formula at an assumed 7 percent real return. Benchmarks: the US personal saving rate published monthly by the Bureau of Economic Analysis has generally run between about 3 and 9 percent of disposable personal income in recent decades, spiking above 30 percent in April 2020. Common planning advice targets 15 percent of gross income including any employer match; rates above 30 percent are associated with early-retirement planning. The main caveats are that a 7 percent real return is a long-run average masking multi-year drawdowns, that 25x assumes a roughly 30-year horizon rather than a 50-year one where sequence-of-returns risk is larger, and that the model holds expenses constant, ignoring health costs, family changes, and lifestyle drift.

The idea that saving is a stable share of income rather than a leftover comes from mid-twentieth-century macroeconomics. John Maynard Keynes formalized the consumption function in the General Theory in 1936; Milton Friedman published the permanent income hypothesis in 1957 and Franco Modigliani and Richard Brumberg developed the life-cycle hypothesis in the mid-1950s, both arguing households smooth consumption across a lifetime rather than spending each period's receipts. The aggregate personal saving rate has been published by the US Bureau of Economic Analysis as part of the National Income and Product Accounts, giving the metric an official series to benchmark against. The use of savings rate as a personal countdown clock to retirement is more recent. Joe Dominguez and Vicki Robin's Your Money or Your Life, published in 1992, reframed spending as hours of life energy and pushed readers toward tracking the gap between income and expenses. The 4 percent withdrawal figure that underpins the 25x target came from research in the mid-1990s, notably William Bengen's 1994 study in the Journal of Financial Planning and the 1998 Trinity Study by three Trinity University professors. In 2012 the blogger Pete Adeney, writing as Mr. Money Mustache, published a widely circulated post converting savings rate directly into years to retirement, which fixed the metric at the center of the FIRE movement.