Sinking Fund Calculator
Set aside the right amount each month for a known future cost.
Enter your values
Enter the amount you need in $.
Enter the months until you need it you are working with.
Enter the interest rate on savings in %.
Enter the already set aside in $.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Monthly deposit
- $457.32
- Weekly equivalent
- $105.53
- Total you deposit
- $8,231.70
- Interest earned
- $268.30
- Existing savings at the deadline
- $530.87
Quick answer
A sinking fund spreads a known future cost across the months before it lands: deposit = goal ÷ the future value factor of a monthly savings stream.
PMT = FV × r ÷ ((1 + r)^n − 1)
At a glance
| What it does | Set aside the right amount each month for a known future cost. |
|---|---|
| Category | Finance |
| Inputs needed | Amount you need, Months until you need it, Interest rate on savings, Already set aside |
| Main output | Monthly deposit |
| Formula | PMT = FV × r ÷ ((1 + r)^n − 1) |
| Cost | Free — no sign-up, no download |
How to use the Sinking Fund Calculator
- 1Enter the total cost you are saving toward.
- 2Enter how many months you have before the bill lands.
- 3Add any money already set aside and the rate your savings earn.
Inputs explained
- Amount you need($)
- Enter the amount you need in $.
- Months until you need it
- Enter the months until you need it you are working with.
- Interest rate on savings(%)
- Enter the interest rate on savings in %.
- Already set aside($)
- Enter the already set aside in $.
Worked example
Using the values the calculator loads with:
Inputs
- Amount you need9000 $
- Months until you need it18
- Interest rate on savings4 %
- Already set aside500 $
Results
- Monthly deposit$457.32
- Weekly equivalent$105.53
- Total you deposit$8,231.70
- Interest earned$268.30
- Existing savings at the deadline$530.87
Frequently asked questions
What is a sinking fund used for?
Predictable, lumpy costs — insurance renewals, car tyres, property tax, Christmas — that wreck a monthly budget when they arrive all at once.
Where should the money sit?
In a separate high-yield savings account named for the goal, so it earns interest and is not spent by accident.
What do I need to enter into the Sinking Fund Calculator?
Just 4 values: amount you need, months until you need it, interest rate on savings, already set aside. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Sinking Fund Calculator work out the answer?
A sinking fund spreads a known future cost across the months before it lands: deposit = goal ÷ the future value factor of a monthly savings stream. It applies the formula PMT = FV × r ÷ ((1 + r)^n − 1) and shows the working so you can check each step by hand.
Is the Sinking Fund Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.