Savings Rate Calculator
Savings Rate Calculator
Work out your savings rate from take-home pay and spending, and how many years that rate puts between you and financial independence, with the classic savings-rate curve.
Savings rate and years to financial independence
$1,00,000 take-home, $60,000 spent a month, $5,00,000 saved, 5% real return, 4% withdrawal
From savings rate to years
- A
- yearly saving: 12 × (income − spending)
- S
- savings and investments now
- g
- real return a year, as a decimal
- n
- years until S grown plus the savings (future value of an ordinary annuity) reaches F
Worked example
$1,00,000 take-home, $60,000 spent a month, $5,00,000 saved, 5% real return, 4% withdrawal
Saving 40,000 of 1,00,000 = 40.0%
FI number = 60,000 × 12 ÷ 0.04 = $1,80,00,000
A = 4,80,000 a year; n = ln[(1,80,00,000 + 96,00,000) ÷ (5,00,000 + 96,00,000)] ÷ ln 1.05 = 20.6 years
From zero it would be 21.6 years; the 5 lakh already saved is worth 1.0 years
Years to financial independence from zero, by savings rate
| Savings rate | 5% real, 4% withdrawal | 4% real, 4% withdrawal | 5% real, 3.5% withdrawal |
|---|---|---|---|
| 10% | 51.4 | 58.7 | 53.9 |
| 20% | 36.7 | 41.0 | 39.0 |
| 30% | 28.0 | 30.7 | 30.1 |
| 40% | 21.6 | 23.4 | 23.5 |
| 50% | 16.6 | 17.7 | 18.2 |
| 60% | 12.4 | 13.0 | 13.7 |
| 70% | 8.8 | 9.1 | 9.8 |
| 80% | 5.6 | 5.7 | 6.3 |
Why the savings rate matters more than income
Your savings rate is the share of take-home pay you do not spend. It drives the time to financial independence twice over: a higher rate means more money invested each year, and a lower level of spending that the portfolio has to support later. Starting from zero, the number of years depends only on the rate, not on how much you earn, which is the point Mr. Money Mustache made in ‘The Shockingly Simple Math Behind Early Retirement’ (13 January 2012), using a 5% real return and a 4% withdrawal rate. At those assumptions a 10% savings rate takes about 51 years and 50% about 17.
The maths is the standard future value of an ordinary annuity: savings added at the end of each year, earning a steady real return, until the pot equals your yearly spending divided by the withdrawal rate. The calculator solves that for the number of years directly, and starts from the savings you already have. Once you have savings, income matters a little too, which is why the chart shows two lines: from your savings now, and from zero.
How it differs from our other FIRE pages. The FIRE calculator starts from the retirement spending and yearly investment you choose, which may differ from each other; this page ties them together through one number, the savings rate, and plots the whole curve. The Coast FIRE calculator asks a different question: when you could stop saving and let growth finish the job. The assumptions carry real uncertainty: returns are not steady, spending in retirement may differ, and a 4% withdrawal rate is a rule of thumb from US market history, examined in the safe withdrawal rate calculator. This is arithmetic on the figures you enter, not financial advice.
Frequently asked questions
How do I calculate my savings rate?
Divide what you save each month by your take-home pay. Saving 40,000 of 1,00,000 is a 40% savings rate.
How many years to financial independence at a 50% savings rate?
About 16.6 years from zero, at a 5% real return and a 4% withdrawal rate. Starting with savings shortens it.
Should the savings rate use gross or take-home pay?
Take-home pay, as the classic curve does, because that is the money you choose to spend or save. Retirement contributions deducted from salary can be added to both income and savings if you want to count them.
Where does the savings rate curve come from?
From the future value of an ordinary annuity, solved for time. It was popularised by Mr. Money Mustache’s 2012 article ‘The Shockingly Simple Math Behind Early Retirement’.
Related calculators
References
- Mr. Money Mustache. The Shockingly Simple Math Behind Early Retirement. 13 January 2012. https://www.mrmoneymustache.com/2012/01/13/the-shockingly-simple-math-behind-early-retirement/ (5% real return, 4% withdrawal rate, starting from zero).
- Brealey RA, Myers SC, Allen F. Principles of Corporate Finance. McGraw-Hill: future value of an ordinary annuity.
- Bengen WP. Determining withdrawal rates using historical data. Journal of Financial Planning, 1994;7(4):171–180.