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Sinking Funds Calculator
List the big costs you know are coming. Type what each one costs, when it is due and what you saved. See how much to set aside each month, pot by pot.
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What to set aside
Type at least one pot: what it costs and when it is due.
- Saved so far
- —
- Still needed
- —
- Each month
- —
| Pot | Still needed | Each month | Each paycheck |
|---|---|---|---|
| Pot 1 | — | — | — |
| Pot 2 | — | — | — |
| Pot 3 | — | — | — |
| Pot 4 | — | — | — |
| Pot 5 | — | — | — |
| Pot 6 | — | — | — |
| Pot 7 | — | — | — |
| Pot 8 | — | — | — |
| Total | — | — | |
How the math works: still needed is the cost minus what you saved. Each month is still needed ÷ months left, rounded up to the next whole dollar, so the pot is full in time. Months left count from your start month up to the due month: a pot due next month has 1 month. Each paycheck is each month × 12 ÷ 26, rounded up. It is an average, since 2 months a year have 3 paydays. A planning tool, not financial advice.
How it works
A sinking fund is money you put aside a little at a time for a big cost you know is coming. Each cost gets its own pot.
- Pick your start month. It starts on this month. Change it if you start later.
- Type each pot. What it costs, the month and year it is due, and what you saved so far. Up to 8 pots.
- Read the answer. For each pot: what it still needs and what to set aside each month. Then the total for all your pots.
The math for each pot:
- Still needed = what it costs − what you saved.
- Months left = the months from your start month up to the due month. Due in April and you start in October? You save in October, November, December, January, February and March. That is 6 months.
- Each month = still needed ÷ months left, rounded up to the next whole dollar. Rounding up means the pot is full in time, with a little to spare.
- Each paycheck (paid every 2 weeks) = each month × 12 ÷ 26, rounded up. You get 26 paychecks a year, so this puts aside at least as much over the year.
The example numbers: 4 pots, each due a few months from now.
A new mattress costs $720, due in 6 months, with $150 saved. It still needs $570. $570 ÷ 6 = $95 a month.
Summer camp costs $1,100, due in 8 months, with nothing saved. $1,100 ÷ 8 = $137.50, so $138 a month.
A laptop: $950 − $210 saved = $740, over 10 months: $74 a month. New glasses: $230 − $50 = $180, over 3 months: $60 a month.
So: set aside $367 a month. Paid every 2 weeks? That is about $171 a paycheck.
Questions people ask
What if a cost is due this month? It has no months left, so it is not in the monthly total. The calculator tells you what it still needs. Find that money now, or move the date if you can.
What if the due date has passed? Type the next date it is due. A bill that comes back every year? Type next year.
A pot is already full. What then? It shows "Ready" and $0 a month. Leave it there until the bill comes.
Why round up? So you never come up short. Rounding up to whole dollars means each pot is full by its date, with a little left over.
I get paid every 2 weeks. Is the paycheck number exact? It is an average. 2 months a year have 3 paydays, so most months you put aside a bit less than the monthly number, and in those 2 months a bit more. For a pot due very soon, put aside the monthly number to be safe.
Is my data saved or sent? No. The math runs on your phone or computer. Nothing is saved. Close the page and it goes back to the example. It is a planning tool, not financial advice.
More free help
- Want it in a spreadsheet? The Sinking Funds Tracker keeps up to 15 pots, shows what to put in each one this month, and says Ready, On track or Behind.
- Saving for goals, not bills? The Savings Tracker keeps up to 10 goals, with how much to save each month and On track or Behind.
- Not sure how much you can set aside at all? Try the free budget calculator. Sinking funds come out of the savings part.
The calculator does the math once. The sheet keeps going.
Want it in a spreadsheet that keeps track?
The Sinking Funds Tracker does that: up to 15 pots, what to put in each one this month, and Ready, On track or Behind for each pot. $1.98 on Etsy, one time.
