How to use
- Enter your savings goal and anything you have already saved.
- Enter the interest rate your savings earn. Use 0 for cash.
- To find the monthly amount, pick the goal date.
- To find the time, switch to How long it will take and enter what you can save each month.
Formula
Monthly saving = (goal − saved × (1 + i)^n) × i ÷ ((1 + i)^n − 1)
Months needed = ln((goal + C ÷ i) ÷ (saved + C ÷ i)) ÷ ln(1 + i)
- i is the monthly rate: (1 + yearly rate)^(1/12) − 1.
- n is the number of months until your goal date, and C the monthly saving.
- Deposits are made at the end of each month. With no interest, it is simply (goal − saved) ÷ months.
Example
Goal: $20,000 in 3 years, with $2,000 saved, at 4% a year.
- Save $465.38 a month for 36 months.
- You put in $18,753.84 in total, and interest adds $1,246.16.
- Without interest you would need $500 a month.
How long instead? Saving $400 a month from the same start reaches $20,000 in 42 months (3 years 6 months).
Monthly saving to reach $10,000
Starting from nothing:
| Time | No interest | 4% a year | 7% a year |
|---|---|---|---|
| 1 year | $833.33 | $818.43 | $807.74 |
| 2 years | $416.67 | $401.19 | $390.21 |
| 3 years | $277.78 | $262.18 | $251.25 |
| 5 years | $166.67 | $151.11 | $140.46 |
Interest helps more the longer you save, but the time you give yourself matters most.
Tips for a realistic plan
- Use your account’s APY, the yearly rate after compounding, or a cautious return for investments.
- Round the monthly amount up, and set up an automatic transfer on payday.
- Long goal? Prices rise too. Add a little to the target for inflation.
Why our figures can differ from other calculators
We convert the yearly rate to a monthly rate so savings grow by exactly that rate each year. Calculators that divide the yearly rate by 12 compound slightly faster, so they show a slightly lower monthly amount.
Saving at the start of each month instead of the end also reaches the goal a little sooner.
Saving for retirement? The retirement calculator also shows how long the money lasts once you start withdrawing.