🎯 Savings Goal Calculator
Enter your target, what you already have saved, how much you can add each month, and an expected interest rate to see how long it takes to reach your goal.
Solving the annuity formula for time
This tool asks the reverse of the usual question, so it
rearranges the future-value formula to make the number of months the unknown -
with r the monthly rate, PMT your
deposit, PV what you have and FV the target:
n = ln((FV x r + PMT) / (PV x r + PMT)) / ln(1 + r)The defaults - a $20,000 goal, $2,000 saved, $300 a month at 4% - give 53.7, which rounds up to 54 months, or 4 years 6 months. Saving the same $300 in a shoebox would take exactly 60 months, so the interest is worth half a year. The tool then replays those 54 months to show the real closing balance of $20,111.03, of which $1,911.03 is interest.
Reading the result
- Months are rounded up. A part month cannot be saved, so 53.7 is shown as 54 and the final balance slightly overshoots the goal.
- The contribution is the big lever. Going from $300 to $400 a month cuts the wait from 54 months to 42 - a third off the time for a third more money, because interest is a small part of a short-horizon goal.
- Use a savings rate, not a market return. Money you need in two years should not be modelled at 7%.
Frequently asked questions
How long will it take to save $20,000?
Starting from $2,000 and adding $300 a month in a 4% account, 54 months. With no interest at all it is 60 months.
How much do I need to save each month for my goal?
Adjust the monthly figure until the months shown match your deadline. For $20,000 in three years from $2,000 saved you need about $465 a month at 4%.
Is interest added before or after my monthly deposit?
Before. Each month the balance grows by the rate, then your deposit lands, so the deposit does not earn in the month it arrives. That matches how most savings accounts credit monthly interest.