Sinking Fund Calculator
Set a target and a date for each irregular expense, and see exactly how much to save per month so it never blindsides your budget.
Free. We'll create a savings Pool for each one, pre-filled with the monthly amount. Nothing to re-enter.
How the sinking fund calculator works
For each expense, enter what you'll need, how many months until you need it, and anything you've already put aside. The monthly amount is simply the remaining target divided by the months left. Add as many funds as you like and the calculator totals what you need to set aside every month across all of them.
Why sinking funds beat willpower
Irregular expenses wreck budgets because they're invisible until they land, and then they land all at once. A sinking fund turns a $600 shock in December into $50 a month you barely notice. It's the same idea behind everything in One Less Choice: decide in advance, so the money is already there and the choice is already made.
Sinking fund FAQ
What is a sinking fund?
A sinking fund is money you set aside a little at a time for a known future expense, so it never blindsides your budget. Instead of getting hit with a $600 car repair or $500 of holiday gifts all at once, you save a small amount each month and the cash is already there when the bill arrives.
How much should I put in a sinking fund each month?
Take the amount you'll need, subtract what you've already saved, and divide by the number of months until you need it. This calculator does that for every fund at once and totals your monthly set-aside, so you can see whether the plan fits your budget before you commit.
What's the difference between a sinking fund and an emergency fund?
An emergency fund is for the unexpected: a job loss or a surprise you can't predict. A sinking fund is for the expected-but-irregular: expenses you know are coming (holidays, insurance premiums, car maintenance, a vacation) even if they don't hit every month. Most households benefit from both.
What should I have sinking funds for?
Common ones include car repairs and registration, the holidays, annual or semi-annual insurance premiums, travel, medical and dental costs, home maintenance, gifts, and back-to-school. Anything that arrives once or twice a year and is big enough to disrupt a single month's budget is a good candidate.
How this is calculated
A sinking fund turns a big, occasional bill into a small, predictable monthly habit. The math is deliberately simple, no compounding tricks, just what you need to set aside so the money is there when the expense lands.
- For each fund, take the amount still needed:
target - already saved. - Divide by the months until you need it:
(target - saved) / months. That's your monthly set-aside. - Add up the monthly set-aside across every fund to get one number to budget each month.
What it assumes
- The money sits in a plain savings account, so no interest is assumed. Any interest you earn is a small bonus on top.
- Costs are known targets you enter; adjust them as real prices (insurance premiums, holiday spending) come in.
- If a deadline is sooner than you can fund, the monthly amount rises accordingly, better to see that now than to be caught short.
Sources
- CFPB: An essential guide to building an emergency fund — official saving-by-goal guidance
Last updated: July 2026 A simple planning estimate, not financial advice. A sinking fund is for expected irregular costs; keep it separate from your emergency fund for true surprises.