Savings Calculator
How much to save each month to reach a goal by a deadline, or how long a goal takes at a set monthly amount.
Your goal
Filled in with example values. Replace them with your own.
Currency symbol
Results update as you type.
Result
Save $464.77 a month for 36 months to reach $20,000.00
Save each month
$464.77a month
- You pay in36 × $464.77
- $16,731.72
- Interest earned
- $1,268.47
- Balance at the endMay be a little over the goal (rounding up)
- $20,000.19
Where the money comes from
- Saved so far
- $2,000.00
- Your deposits
- $16,731.72
- Interest
- $1,268.47
- Final balance
- $20,000.19
How it’s calculated
Monthly rate
4% ÷ 12 = 0.333%
Deposit needed, rounded up
(goal − savings grown) ÷ growth of 1 a month = $464.77
How the savings calculator works
Choose what you want to know. If you have a deadline, the calculator works out how much to save each month to reach your goal in time. If you know how much you can put aside, it works out how long the goal will take. In both cases it counts what you have already saved and the interest it earns.
The formula
Balance after N months = S(1 + i)^N + D × ((1 + i)^N − 1) ÷ i
D = (G − S(1 + i)^N) × i ÷ ((1 + i)^N − 1)
N = ln((G × i + D) ÷ (S × i + D)) ÷ ln(1 + i)
G is the goal, S what you have saved, D the monthly deposit and i the yearly rate ÷ 12. At 0% these become (G − S) ÷ N and (G − S) ÷ D.
Worked examples
Saving for a deadline
To reach 20,000 in 3 years, starting from 2,000, in an account paying 4%: you need to save 464.77 a month. Without interest it would be 18,000 ÷ 36 = 500.
Saving a fixed amount
Saving 500 a month towards the same goal takes 33.6 months, so you reach it in 34 months (2 years and 10 months).
Assumptions and limitations
- Interest is added monthly at a fixed yearly rate ÷ 12.
- Deposits are made at the end of each month, in the same amount every month.
- Tax, fees and inflation are not included.
Frequently asked questions
Why is the monthly amount rounded up?
Rounding down by even a cent would leave you just short of the goal, so the deposit is rounded up to the next cent and the time up to the next whole month. The final balance may therefore be slightly above the goal.
What if my savings account pays interest differently?
The calculator assumes interest is added monthly at the yearly rate ÷ 12. Accounts that pay quarterly or yearly, or whose rate changes, will give slightly different results.
What does “no deposits needed” mean?
Your current savings will grow past the goal from interest alone within the time you entered, so you do not need to add more.
Is the interest taxed?
The calculator does not include tax. Whether savings interest is taxed, and how much, depends on where you live and the type of account.