Sinking Fund Calculator
Plan for insurance, car registration and Christmas. Get the monthly set-aside per fund, months left, and your combined monthly sinking fund total.
Sinking Fund Calculator
Your sinking funds
One line per fund: what it is for, the full amount you need, the month the bill lands, and anything you have already put aside. A row with no name or no target is skipped, so spare rows can sit open while you think.
The amounts are placeholders, not advice. Overwrite every one of them with your own numbers. Due dates are set relative to this month, so nothing loads already past due.
Up to 20 funds. Enter the full bill in the target, not the monthly piece, and leave "already saved" blank if you are starting from zero. Removing a fund clears whatever was in that row.
Nothing counted yet. Give a row a name and a target above and the plan fills in as you type.
The year figure is the monthly total times 12, not the sum of your targets. We round each monthly amount up to the nearest cent so you always land on or just above your target.
Fund by fund
| Fund | Target | Saved | Progress | Due | Months left | Monthly | Status |
|---|
The rows always add up to the headline total exactly, because the total is the sum of the rounded per-fund amounts rather than a separate calculation.
What is coming, in order
Sorted by due date rather than by the order you typed them. Anything past due or due this month sits at the top.
How to work out your monthly sinking fund amount
The formula is one line: the total you need, minus what you have already saved, divided by the whole months before it is due. Car insurance of $1,200 that lands in March, with $300 already put aside and seven months to go, is $900 divided by 7, which is $128.58 a month. No row on this page is doing anything harder than that.
One convention is worth spelling out, because it is where hand calculations and calculators usually disagree. The due month itself does not count as a contributing month. You need the cash when the bill lands, not at the end of the month it lands in, so a fund due next month has exactly one month left, and a fund due this month has none. Counting from August 2026, a March 2027 bill is seven months out: August through February.
Each monthly amount is rounded up to the nearest cent, so the monthly figure times the months left always covers the remaining balance. Rounding down, or rounding to nearest, can leave you a few cents short on the due date, which is the one thing a sinking fund is meant to stop. The overshoot is at most a cent a month.
There is no interest-rate box here on purpose. Sinking funds are short-horizon cash sitting in a savings account for three to eighteen months, where a few percent moves the monthly figure by pennies and makes the result impossible to check by hand. If you got here from a finance-math search, one note: the corporate meaning of "sinking fund", where an issuer sets money aside to retire a bond at maturity and the answer involves a uniform-series factor, is a different calculation entirely. This page is the household version.
Which expenses deserve a sinking fund
The membership test is short: it is a sinking fund if you can name the expense and put a month on it. Anything you cannot name or cannot date belongs in the emergency fund instead, because that pot exists for the unscheduled.
The usual list runs: car insurance, car registration and inspection, tires and maintenance, property tax, home repairs, appliance replacement, medical and dental, Christmas and birthdays, vacation, annual subscriptions, back to school, and pet care. A $1,200 insurance renewal is $100 a month across a full year. A $600 set of tires you want in ten months is $60 a month. A $480 gift budget spread over twelve months is $40 a month. Individually none of those is frightening.
Together they are the whole point. Plenty of households are running six or seven of these at once, and the number that decides whether the plan survives is the combined monthly total, not any single fund. That is the figure at the top of this page, and it is the line that has to fit inside this month's budget alongside rent and groceries. To see the same problem laid out by date rather than by category, read budget calendar: projected vs actual spending .
Where the money actually sits
One savings account holding all the funds, with the split tracked on paper or in an app, beats ten separate accounts. What matters is that the money is separated from spending money and that you can see each fund's balance without doing arithmetic first.
In Budget44 a sinking fund is a saving goal. It takes a name, a target amount and an optional deadline, then shows a progress ring with saved of target, remaining to target, percent complete and days to deadline. Contributions are deposits recorded as transactions linked to the goal. If you would rather treat the monthly set-aside as a bill you pay yourself, a recurring transaction on a monthly cadence does that instead and shows up on the calendar and in the Upcoming list. Everything is entered by hand and stored on the device, with amounts held as integer minor units, so the balances stay exact to the cent. No account, no cloud sync, no bank connection. That manual, on-device approach is covered in how to track expenses without linking a bank account .
Got your monthly number? Download Budget44 and set the funds up as goals you can actually watch fill.
When the plan slips
Three failure modes, and a fix for each. The first: the combined total is more than you can save. Cut a target, push a date out, or drop a fund. The table recalculates as you type, so you can see exactly what each trade buys you before you commit to it.
The second: a fund is due next month and is short. The calculator flags it and shows the whole gap as needed now rather than quietly printing a soothing monthly figure that cannot arrive in time. Past-due funds get the same treatment and sort to the top of the upcoming list.
The third: you raided a fund for something else. Update the already-saved figure and rerun. The monthly amount goes up, which is the honest consequence, and it is much better to find that out in August than in December. For the month-to-month version of the same habit, see digital envelope budgeting on your phone .
Frequently Asked Questions
Common questions about sinking fund calculator
What is a sinking fund?
Money set aside a little at a time for a specific expense you know is coming on a specific date: the insurance renewal, the registration, Christmas, new tires. Instead of one $1,200 hit in March, it becomes twelve pieces you barely feel. The bill stops being an emergency because you already paid for it.
How do I calculate how much to save each month?
Take the total you need, subtract what you have already put aside, and divide by the number of whole months before it is due. $1,200 of insurance due in March, $300 already saved, seven months to go: $900 divided by 7 is $128.58 a month. That is the whole formula, and this calculator runs it on every row at once so you also get the combined total.
What is the difference between a sinking fund and an emergency fund?
A sinking fund is for the known: you can name the expense and put a date on it. An emergency fund is for the unknown, the job loss or the failed transmission nobody scheduled. The usual advice is three to six months of living costs in the emergency fund. Sinking funds sit alongside it and get spent on purpose.
How many sinking funds should I have?
Enough to cover the irregular bills that actually knock your month sideways, usually five to ten. There is no hard cap, but every fund is a line in your monthly budget, so the practical limit is what the combined monthly total can bear. That total is the point of this page: run all your funds together and see the real number before you commit to it. If your income moves month to month, set a safe baseline first with the irregular income budget calculator.
What if I cannot afford the monthly amount the calculator gives me?
Three levers, and only three. Lower the target (a $600 Christmas instead of $1,000). Move the date out if the expense is flexible. Or drop a fund entirely and accept you will handle it another way. Shrinking a fund on purpose beats missing every fund by a little. To see which paycheck actually carries the monthly figure, run it through the biweekly paycheck budget calculator.
What are the most common sinking fund categories?
Car insurance, car registration and inspection, tires and maintenance, property tax, home repairs, appliance replacement, medical and dental, Christmas and birthdays, vacation, annual subscriptions, back to school, and pet care. Anything that arrives once or twice a year rather than monthly is a candidate. For the annual-subscription row, the subscription cost calculator gives you a real target instead of a guess.
What if my sinking fund is already past its due date?
The calculator stops spreading it and shows the full remaining amount as needed now, flagged Past due. That is the honest answer. Cover it from whatever you can, then reset the fund with the next due date so the same bill does not ambush you again next year. A budget calendar is the usual way people stop being surprised twice.