Sinking Funds Explained: Plan for Expenses That Are Not Monthly
Reviewed by ThriVelo · Last reviewed August 9, 2026
Short answer: A sinking fund is money set aside gradually for a known future expense. It helps turn annual, seasonal, or irregular costs into smaller contributions instead of last-minute financial shocks.
What is a sinking fund?
A sinking fund is a planned pool of money for an expense that is expected but does not happen every month. You contribute over time so the money is available when the expense arrives.
This is different from an emergency fund. A sinking fund is usually for something you can reasonably anticipate, while an emergency fund is designed for unexpected events and uncertainty.
Examples of sinking funds
- Vehicle maintenance and repairs.
- Insurance premiums paid annually.
- Holiday gifts and seasonal celebrations.
- School supplies or tuition-related expenses.
- Home maintenance.
- Annual subscriptions and renewals.
- Travel, events, or planned visits.
- Medical or dental expenses you expect to occur.
How to calculate a contribution
Example: If you expect a $600 vehicle expense in 12 months, setting aside about $50 per month would build the full amount over that period. If you are paid biweekly, you could divide the target across the number of paycheques before the expense.
The estimate does not need to be perfect. It should be based on the best information you have, then adjusted when the amount or timing becomes clearer.
How to set up a sinking fund
1. Name the expense
Use a specific name such as “car repairs,” “winter clothing,” or “annual insurance.” Specific names make the purpose easier to remember.
2. Estimate the target amount
Look at previous costs, current quotes, renewal notices, or a reasonable estimate. It is better to start with a useful estimate than to treat the expense as invisible.
3. Identify the deadline
The amount of time available determines how much needs to be set aside each week, month, or paycheque.
4. Keep the money visible
Use a separate account, sub-account, spreadsheet, envelope, or other system that helps you know the money has a purpose.
Common sinking-fund mistakes
- Forgetting expenses that happen only once or twice a year.
- Using sinking-fund money for ordinary flexible spending.
- Setting a target without considering the deadline.
- Creating so many funds that tracking becomes exhausting.
- Confusing a sinking fund with a general emergency fund.
Predictable does not mean monthly. If an expense is likely to happen, it deserves a place in the plan even when it does not appear on every monthly statement.
Where ThriVelo fits
Sinking funds help organize future obligations. ThriVelo helps connect those obligations to the current paycycle by showing how upcoming bills and expenses affect what is safe to spend today.
Make future expenses easier to account for.
See what is realistically available after the money that needs to last has been considered.
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