Sinking Funds: The Budgeting Trick for Irregular Expenses
In this guide
- What is a sinking fund?
- Sinking fund vs. emergency fund
- Common sinking funds to set up
- How to calculate your monthly amount
- Example: a complete sinking fund plan
- Where to keep sinking funds
- How sinking funds fit into your budget
- Tips for sinking fund success
- What if a sinking fund runs short?
- Building your sinking fund list in 30 minutes
- Frequently asked questions
- Never be surprised again
Most budgets break in the same way: not because of a true emergency, but because of an expense that was completely predictable. The car registration due every year. Holiday gifts in December. The annual software subscription. The new tires your car needs every few years.
Sinking funds solve that problem. They’re one of the simplest and most effective budgeting tools there is, and they keep your emergency fund for actual emergencies. Here’s how they work, which ones to create and exactly how to set them up.
What is a sinking fund?
A sinking fund is money you set aside a little at a time for a specific, expected expense. Instead of paying $600 all at once when a bill arrives, you save $50 a month for 12 months, and the money is waiting when you need it.
The term comes from corporate finance, where companies set aside money over time to repay bonds. For personal budgets, the idea is the same: spread big, irregular costs into small, predictable monthly amounts.
Sinking fund vs. emergency fund
| Sinking fund | Emergency fund | |
|---|---|---|
| Purpose | Expected, planned expenses | Unexpected, urgent expenses |
| Timing | You know roughly when and how much | You don’t know when or how much |
| Examples | Insurance premiums, gifts, car maintenance, travel | Job loss, medical emergency, sudden major repair |
| How many | Several, one per goal | Usually one |
Without sinking funds, predictable expenses often end up paid from your emergency fund or put on a credit card. Our guide to building an emergency fund explains why keeping the two separate matters.
Common sinking funds to set up
| Sinking fund | Typical cost | Frequency |
|---|---|---|
| Car insurance (if paid every six or 12 months) | $600–$1,800 | Semiannual or annual |
| Car maintenance and repairs | $500–$1,200 | Yearly average |
| Car registration and inspection | $100–$400 | Annual |
| Holiday and birthday gifts | $500–$1,500 | Annual |
| Travel and vacations | $1,000–$3,000 | Annual |
| Annual subscriptions and memberships | $100–$500 | Annual |
| Medical and dental out-of-pocket costs | $300–$1,500 | Yearly average |
| Clothing | $300–$1,000 | Yearly average |
| Pet care (vet visits, grooming) | $300–$1,000 | Yearly average |
| Home or apartment items (furniture, moving costs) | Varies | Varies |
| Electronics replacement | $1,000–$1,500 | Every 3–4 years |
| Wedding attendance and events | $500–$2,000 | Varies |
Ranges are rough examples; base your amounts on your own past spending.
You don’t need all of these. Start with the three to five expenses that have caught you off guard in the past year.
How to calculate your monthly amount
Monthly contribution = total cost ÷ months until you need it
Examples:
- $1,200 holiday budget, needed in 10 months: $1,200 ÷ 10 = $120/month
- $900 car insurance premium due in 6 months: $900 ÷ 6 = $150/month
- $1,200 laptop replacement in 36 months: $1,200 ÷ 36 = $33/month
Example: a complete sinking fund plan
Taylor reviews last year’s bank statements and finds these irregular costs:
| Sinking fund | Annual cost | Monthly contribution |
|---|---|---|
| Car insurance (paid twice a year) | $1,200 | $100 |
| Car maintenance and registration | $900 | $75 |
| Gifts and holidays | $900 | $75 |
| Travel | $1,800 | $150 |
| Annual subscriptions | $240 | $20 |
| Medical copays and dental | $600 | $50 |
| Total | $5,640 | $470 |
Saving $470 a month means Taylor will never again be surprised by $5,640 of “unexpected” costs over the year.
Where to keep sinking funds
High-yield savings with buckets: Many online banks let you create multiple savings goals or sub-accounts within one high-yield savings account. Name each bucket, set a target and automate deposits. Read our guide to high-yield savings accounts.
Separate savings accounts: Some people prefer a separate account for each major fund, especially travel or holidays.
One account with a spreadsheet: Keep all sinking fund money in one savings account and track each fund’s balance in a spreadsheet.
Avoid keeping sinking funds in your checking account, where they’re easy to spend accidentally.
How sinking funds fit into your budget
Treat sinking fund contributions like any other bill:
- With the 50/30/20 rule: essential sinking funds (car insurance, medical) fall under needs; travel and gifts fall under wants.
- With zero-based budgeting: each sinking fund gets its own budget line.
- With pay-yourself-first: automate transfers on payday along with your other savings.
Tips for sinking fund success
- Start with your biggest surprises. Look at your last 12 months of statements for irregular expenses.
- Automate contributions on payday.
- Name each fund clearly, so you know exactly what the money is for.
- Use the money guilt-free. When the bill arrives, pay it from the fund. That’s the whole point.
- Review once or twice a year. Adjust amounts as costs change.
- Start small if needed. Even $10 a month in three funds is better than nothing.
What if a sinking fund runs short?
Sometimes the bill is bigger than expected. Options:
- Move money from a less urgent sinking fund
- Cut back on a flexible category for a month
- As a last resort, use your emergency fund, then rebuild it
Then increase that fund’s monthly contribution for next time.
Building your sinking fund list in 30 minutes
You don’t need to guess which funds you need. Your past spending already tells you. Here’s a quick method:
- Download 12 months of bank and credit card statements.
- Search for large or unusual charges. Look for anything above about $100 that doesn’t happen every month.
- Search for annual renewals. Subscriptions, memberships, domain names and software often renew once a year.
- Check your calendar. Birthdays, holidays, weddings and trips you already know about.
- Look ahead. Will your phone or laptop need replacing in the next few years? Is your car getting older?
- Group similar items into five to eight funds.
Example: what one person found
| Charge found in statements | Month | Amount | Fund |
|---|---|---|---|
| Car insurance (six-month premium) | March and September | $560 each | Car insurance |
| Tires and alignment | May | $720 | Car maintenance |
| Flights home for the holidays | November | $480 | Travel |
| Gifts | December | $650 | Gifts |
| Annual subscriptions | Various | $210 | Subscriptions |
| Friend’s wedding (travel and gift) | July | $900 | Events |
| Dental crown copay | August | $350 | Medical |
That’s $4,430 of “surprises” in one year, or about $370 a month. None of them were true emergencies, and every one could have been planned.
How to stay motivated
- Name each fund with its purpose, such as “December gifts” or “Tires 2027.”
- Watch the balances grow. Many banking apps show progress bars for savings goals.
- Celebrate using the money. Paying a $560 insurance premium without touching your checking balance or a credit card is the system working.
If you’re new to budgeting, start with the basics in our guide to making a budget, then add sinking funds one at a time.
Frequently asked questions
How many sinking funds should I have?
Most people do well with four to eight. Too many can become hard to manage; too few may miss important expenses.
Should I build sinking funds or pay off debt first?
Ideally both. Sinking funds prevent new debt by covering predictable expenses. Start a small starter emergency fund and a few key sinking funds while paying down high-interest debt using a plan like the debt snowball or avalanche.
Are sinking funds the same as savings goals?
They’re similar. A sinking fund is a savings goal for a specific expected expense with a known approximate cost and date.
What’s the difference between a sinking fund and a budget category?
A budget category covers monthly spending. A sinking fund accumulates money across months for an expense that happens less often.
Should sinking funds earn interest?
Yes, when possible. Keeping them in a high-yield savings account lets your money earn interest while it waits.
Never be surprised again
Sinking funds turn irregular but predictable expenses into small monthly savings. Identify your recurring irregular costs, divide each by the months until it’s due, automate contributions to labeled savings buckets and spend the money guilt-free when the bill arrives.
Pick one today: Scan your last year of bank statements for three irregular expenses that caught you off guard. Create a savings bucket for each and set up automatic monthly transfers. For more ways to free up money for your funds, see our list of practical ways to save money.