A sinking fund is money you set aside each month for a cost you know is coming but do not pay every month, such as car insurance, holiday gifts or an annual membership. List each cost, when it is due and what you have already saved, and this calculator shows the monthly amount for each fund and the total.
A worked example
These hypothetical costs use US dollars and assume that the stated number of full monthly contributions can be made before each due date.
| Expense | Cost | Due in | Saved | Each month |
|---|---|---|---|---|
| Car insurance | 720 | 6 months | 120 | 100.00 |
| Holiday gifts | 900 | 9 months | 0 | 100.00 |
| Car registration | 180 | 12 months | 0 | 15.00 |
| Annual app plan | 119 | 10 months | 0 | 11.90 |
The total is 226.90 a month. Adding it to the monthly budget makes these planned costs visible; covering them still depends on making the contributions and keeping the money reserved.
Sinking fund or emergency fund?
A sinking fund is for costs you can predict; an emergency fund is for costs you cannot. Keeping them apart stops a known bill from using up your emergency money. Plan the emergency side with the emergency fund calculator.
Finding costs to include
Look back through the last twelve months of statements for anything paid once, twice or a few times a year. The CFPB savings plan tool is designed for exactly these costs, listing examples such as car insurance, renter’s insurance, back-to-school costs, birthdays and holidays. Add annual subscriptions too; the subscription cost calculator can help you find them.
How the calculation works
For each fund, the amount still needed is the cost minus what you have saved, divided by the months until it is due. Monthly amounts are rounded up to the next cent so rounding does not leave a shortfall. If a cost has already been fully saved, its monthly amount is zero. After paying a bill, plan its next due date with the amount actually left in that reserve.
The calculation assumes costs and due dates stay unchanged, every monthly contribution is made and no reserve is used elsewhere. It accepts 1–120 whole months; a bill due now or before your next contribution needs a separate cash check, not a one-month plan. Enter all costs and reserves in one currency. Display currency changes labels only. This is educational planning, not a promise that a bill will be covered or personalized financial advice.
Add the monthly total as a goal line in the monthly budget template.