Payment per period (A)
—
- A
- uniform amount per period
- F
- future value target
- i
- interest rate per period
- n
- number of periods
Worked example · Reaching $5,000 in 7 years at 5% needs $614 set aside each year.
Eq.04 · Uniform series
Sinking Fund Calculator
Use this sinking fund calculator to size equal deposits for sinking funds — regular contributions that grow with interest to a future value target F.
A = F · i / [(1 + i)^n - 1]
How to use this calculator
- 1 Enter your future goal as F (future value target)
- 2 For monthly deposits, divide your yearly interest rate by 12 to get the monthly rate i (e.g. 5% per year → enter 0.4167% per month), and enter the number of months as n
- 3 Read A — your required deposit each month
Examples
Reaching $5,000 in 7 years
This is the default sinking fund example — equal yearly deposits that grow with interest to hit a savings goal.
Given: F = $5,000, i = 5% per year, n = 7 years
Result: A = $614 per year
Equipment replacement fund
Sinking funds are widely used by businesses to save toward replacing equipment at a known future cost.
Given: F = $50,000, i = 6% per year, n = 10 years
Result: A = $3,793 per year
Sinking fund calculator with monthly deposits
For a monthly deposits formula, divide the yearly rate by 12 and count months instead of years — this example saves toward a $10,000 goal in two years.
Given: F = $10,000, i = 0.4167% per month (5% per year ÷ 12), n = 24 months
Result: A = $397 per month
Frequently asked questions
What is a sinking fund?
A sinking fund is a plan of equal periodic deposits that grow with interest to reach a set future amount F.
What is the sinking fund formula?
A = F · i / [(1 + i)^n - 1]
How do I calculate sinking fund deposits?
Enter future goal F, interest rate i, and periods n. For monthly deposits, see the monthly deposits question below.
What is an example of a sinking fund?
To reach $5,000 in 7 years at 5%, set aside $614 each year.
How do I use the sinking fund calculator with monthly deposits?
Enter goal F, set i to the yearly rate divided by 12 (e.g. 5% per year → 0.4167% per month), and set n to the number of months (e.g. 24 months for 2 years). Result A is your monthly deposit.