How Long It Takes To Reach A Savings Goal Calculator

A savings goal has three moving parts — what you already have, what you add each month, and what compounding quietly adds on top. The third one is the reason rounding your monthly figure to a nice number can push your finish line out by years.

Savings target($)Amount already saved($)Zero works fine as long as the monthly deposit is above zero.Deposit each month($)Annual yield (APY)(%)Set this to 0 to see the interest-free timeline for comparison.

Months to reach the goal

73.95

Years to reach the goal: 6.1625
Total you contribute: $41,974.98
Supplied by compounding: $8,025.02

Values update as you type. This calculator covers the single scenario its formula assumes — see Common Mistakes for what it leaves out.

The formula this calculator uses

n = ln((FV x r + PMT) / (PV x r + PMT)) / ln(1 + r)

n: Number of periods (months if deposits and rate are monthly)
FV: Target balance you want to reach
PV: Amount already saved today
PMT: Deposit made at the end of each period
r: Periodic interest rate — annual rate divided by periods per year

How to check the result by hand

1
Set the target in future dollars
If the goal is tied to a purchase years away, inflate today's price by expected inflation before you start. A target set in today's dollars is a target for today's purchase, not the one you will actually make.
2
Convert the annual yield to a periodic rate
Divide the APY by 12 for monthly deposits, or by 26 for fortnightly. A 5% APY becomes r = 0.00416667. Using 0.05 as the monthly rate makes every answer absurd.
3
Build the ratio inside the logarithm
Numerator: target times r, plus the deposit. Denominator: starting balance times r, plus the deposit. For $50,000, $5,000, $500 and r = 0.00416667 that is (208.33333 + 500)/(20.83333 + 500) = 708.33333/520.83333 = 1.3600000.
4
Divide by the log of the growth factor
ln(1.3600000) = 0.3074847 and ln(1.00416667) = 0.00415801. The quotient is 73.95 months, or about 6.2 years. Computing with full precision matters here — rounding the intermediate logs to four places shifts the answer by several months.
5
Split the result into deposits and growth
Contributions are $5,000 + $500 x 73.95 = $41,974.98, leaving $8,025.02 of the $50,000 earned by interest. That is 16.05% of the target — enough that a smaller assumed return would visibly move the finish line.

For worked examples, common mistakes and the limits of this formula, read the full How To Calculate How Long It Takes To Reach A Savings Goal page.