Sinking fund calculator
A sinking fund turns a scary one-off bill into a small, boring monthly transfer. Put in the cost and the date and we will tell you what to move each month.
Set aside
$125.00
per month — about $28.93 a week
$1,000.00 still needed over roughly 8 months.
How to actually run a sinking fund
Keep it out of your day-to-day account. A separate savings pot or an envelope in your budget stops the money getting quietly spent. Automate the transfer for the day after payday so it happens before anything else.
When the expense lands, spend the fund without guilt and restart the clock for next year. Running several funds at once is normal — the point is that no single month has to absorb the whole bill.
How the sinking fund calculator works
- 1
Name the expense and its true cost
Use the full amount you will actually hand over — insurance premium, car service, Christmas, school fees or the annual subscription renewal.
- 2
Enter what you have already put aside
Any existing balance earmarked for this expense reduces what you still need, so the monthly figure reflects reality.
- 3
Set the date the money is needed
The deadline drives everything. The calculator converts the time remaining into whole months and a weekly equivalent.
- 4
Automate the transfer
Move the monthly amount to a separate savings pot or envelope the day after payday, before the money can be spent elsewhere.
- 5
Restart the fund after you spend it
Once the bill is paid, reset the target for next year. Recurring annual costs should never be a surprise twice.
Assumptions this calculator makes
- Contributions are level — the same amount every month until the deadline.
- Months are averaged at 30.44 days, so a mid-month deadline rounds to the nearest whole month.
- Interest earned on savings is ignored, which keeps the target slightly conservative.
- Inflation on the future price is not applied — add a buffer for costs that rise each year.
Frequently asked questions
- What is a sinking fund?
- A sinking fund is money set aside a little at a time for a known future expense — car tyres, insurance renewal, Christmas, a holiday. Unlike an emergency fund, the amount and the date are both predictable, so you can divide the cost across the months you have left.
- How is a sinking fund different from an emergency fund?
- An emergency fund covers surprises you cannot plan for and stays untouched otherwise. A sinking fund is for an expense you already know is coming, and it is meant to be spent.
- How many sinking funds should I have?
- One per predictable irregular expense. Most people run three to six: car maintenance, annual insurance, holidays, gifts, home repairs and tech replacement.
Run every sinking fund in one place
MoneyQuilt turns each future bill into an envelope that fills automatically as you get paid, so annual costs never land on a single month's budget again.
Free to start · no card required