Money
Savings goal calculator
Enter a goal, what you have saved, the time you have, and the interest rate on the account. You get the monthly deposit that reaches the goal.
What this means
- Saving $464.77 a month for 3 years reaches $20,000.00.
- Interest covers about $1,268.46 of the goal. The rest comes from your deposits and current savings.
What if
About this calculator
What this calculator does
It works backward from a goal. It grows what you already have to the goal date, then finds the level monthly deposit that covers the rest.
How it is calculated
grown savings = S * (1 + i)^N
monthly deposit = (G - grown savings) * i / ((1 + i)^N - 1)
with no interest: (G - S) / N
G is the goal, S the current savings, i the annual rate divided by 12, and N the number of months.
How to read the result
The monthly figure is what to set aside at the end of each month. If your current savings grow past the goal on their own, the monthly figure is zero.
Sources and method
Standard arithmetic with no outside data. The formula is shown under How it is calculated, and unit tests check worked examples, including edge cases.
This page uses arithmetic only, with no outside data.
Questions
Does it assume deposits at the end of the month?
Yes. Saving at the start of each month would need slightly less.
What if my rate changes?
Run it again with the new rate. The page uses one rate for the whole period.
Should I include the interest rate at all?
Use the rate your savings account pays. For cash at home, use 0.
Are taxes on interest included?
No. Interest may be taxable, which would reduce the growth a little.