How to use it
Enter the amount you're aiming for, what you've already put away, and how many years until you need it. Leave the return at 0% for short-term goals you'll keep in savings; add a modest return for long-horizon goals where the money will be invested. The result is the monthly amount that gets you to your number on time.
The math behind it
With no growth, it's just arithmetic: (goal − already saved) ÷ months. A $25,000 down payment in 5 years is $25,000 ÷ 60 = about $417 a month — your real target, not a percentage of income. When you add an expected return, the tool accounts for compounding on both your current balance and each contribution, which lowers the monthly amount needed.
Why "save 20%" misses the point
A generic percentage assumes no specific goal and no deadline. The number that actually matters is the one that gets you to your goal by your date. If that comes out to 12% of your income, great; if it's 30%, you've learned you need a longer timeline, a smaller goal, or more income — which is far more useful than a rule of thumb.
Frequently asked questions
Include growth or not? No growth for goals a few years out; add a return for long-term goals that will be invested.
What return should I use? Be conservative — a broad index has historically averaged around 7% before inflation over long periods, but any single year is unpredictable.