Sinking funds: what they are and how to set them up
A sinking fund is money you put aside a little each month for a cost you know is coming, like car insurance, holiday gifts or a trip. When the bill arrives, the money is already there, so it doesn't go on a credit card or wreck that month's budget.
Updated October 29, 2026
What a sinking fund is
You pick a future expense, work out what it will cost and when it's due, and save the same amount each month until then. The name comes from corporate finance, where a company sets money aside every year to repay a bond when it comes due. A household version works the same way with smaller numbers.
Sinking funds are for costs that are predictable but don't come every month. Most budgets handle rent and groceries well because they arrive on schedule. The trouble comes from the bills that show up once or twice a year: they feel like emergencies, even though you could have named them in January.
How much to save each month
Monthly amount = cost ÷ months until it's due
Car insurance of $900 due in 9 months needs $100 a month. If you already have some saved, divide what's left instead: $900 with $300 saved and 6 months to go is ($900 − $300) ÷ 6, which is also $100 a month.
Some costs have no fixed date, like car repairs or vet visits. For those, take what you spent on them over the last year and divide by 12. If you don't know the figure, go through a year of card and bank statements, or make a sensible guess and adjust it after a few months.
Sinking fund categories
These are the costs people most often save for this way. You don't need all of them. Start with the two or three that caught you out last year.
| Category | What it covers |
|---|---|
| Car insurance | Premiums paid every 6 or 12 months |
| Car maintenance | Oil changes, tires, brakes, registration, inspections |
| Holidays and gifts | December, birthdays, weddings, baby showers |
| Travel | Flights, hotels and spending money, including trips home |
| Home repairs | Appliances, plumbing, a new water heater; for renters, moving costs |
| Medical and dental | Deductibles, copays, glasses and contacts, dental work |
| Annual subscriptions | Memberships, software and anything else billed once a year |
| Pets | Yearly vet visits, vaccinations, boarding when you travel |
| Kids and school | Back-to-school supplies, camp, sports fees, school trips |
| Clothing | Seasonal clothes, work clothes, shoes that wear out |
| Electronics | Replacing a phone or laptop every few years |
| Taxes and fees | Property tax not paid through a mortgage, estimated tax on side income |
A sinking funds example
Here's a set of six sinking funds for one household, with what each costs over a year. The amounts are illustrations.
| Fund | Per year | Per month |
|---|---|---|
| Car insurance | $1,080 | $90 |
| Car maintenance | $720 | $60 |
| Holidays and gifts | $900 | $75 |
| Travel | $1,800 | $150 |
| Medical and dental | $600 | $50 |
| Annual subscriptions | $240 | $20 |
| Total | $5,340 | $445 |
On take-home pay of $4,000 a month, $445 is about 11%. That looks like a lot until you remember the $5,340 gets spent either way. Without the funds it comes out in lumps, often on a credit card, and then costs interest too.
The funds don't change which bucket a cost belongs to. In the 50/30/20 rule, car insurance and medical costs are needs, and travel and gifts are wants. The funds just spread them evenly across the year.
Sinking funds vs savings and emergency funds
All three are savings. The difference is what the money is for and whether you expect to spend it.
- A sinking fund is for costs you know are coming. You plan to spend it on schedule, and it only has to hold the cost of each item. An ordinary savings account is fine.
- An emergency fund is for costs you can't predict, like losing a job. You hope never to spend it. A common target is three to six months of essential costs, kept in separate savings you can reach quickly.
- Long-term savings are for goals years away, like a home or retirement, and usually sit in retirement or investment accounts.
The usual mix-up is between a sinking fund and an emergency fund. If every car repair comes out of the emergency fund, it keeps getting drained by things that aren't emergencies, and it's never full when a real one comes. A car will need tires; you just don't know which month.
Where to keep sinking funds
- One savings account and a list. All the funds sit in one account, and a note or spreadsheet records how much of the balance belongs to each. It's simple and earns interest, but the list has to be kept up to date.
- Savings buckets. Some banks let you split one savings account into named goals, so each fund shows its own balance without a separate list.
- Separate accounts. One account per fund keeps them strictly apart, at the cost of more accounts to manage.
- Cash envelopes. They work for small funds you spend in cash, like gifts. See the envelope method.
Whichever you choose, automate it. Set up one transfer on payday for the total, then split it across the funds. Our guide on how to budget your paycheck shows where that transfer fits.
When it's time to spend
When the bill comes, pay it from the fund, or pay from your everyday account and move the same amount over from the fund. Then:
- If it cost less than you saved, leave the rest in the fund for next time or move it to another goal.
- If it cost more, cover the gap from this month's flexible spending, and raise the monthly amount for next year.
- If you borrow from one fund to cover another, write it down and pay it back. Otherwise the second bill arrives to an empty fund.
- After a yearly payment, the fund goes back to zero and starts again the next month.
Tracking sinking funds
Moving money into a sinking fund isn't spending. It's the same money in a different account, just as an ATM withdrawal moves money into your wallet. If you log each transfer as an expense and then log the purchase when it happens, you've counted the cost twice. Log the purchase when you make it, and leave the transfers out.
