Sinking Fund Calculator
| Goal | Target | Months | Per month |
|---|---|---|---|
| Holidays | $1,200 | 12 | $100 |
| Car repairs | $1,500 | 12 | $125 |
| Insurance premium | $900 | 6 | $150 |
| Phone upgrade | $1,000 | 24 | ~$42 |
A sinking fund is savings with a name on it: not an emergency fund for unknowns, but a quiet monthly amount for expenses you can see coming - the holidays every December, the car tabs every spring, the insurance premium that arrives like a tax. The math is one division: target divided by months, and the surprise is gone.
Bottom line: a $1,200 holiday spent on a credit card at 24 percent and paid over a year costs about $1,350; the same holiday funded at $100 a month costs $1,200 and arrives with zero interest. Sinking funds are the cheapest debt prevention ever invented, and they require only a calendar and a separate spot for the money.
The honest part: the system fails the way gym memberships fail - not at the math but at month four, when the fund is half full and the expense still feels far away. Automating the transfer on payday is the difference between a sinking fund and a jar that gets raided; separate accounts beat willpower every time.
How to use
- Enter what the thing will cost and the month you need it - be honest about the number, and pad the irregular ones by 10 percent.
- Read the monthly and per-paycheck amounts, then automate the transfer for payday morning before anything else moves.
- Keep each fund in its own labeled spot - a savings account per goal, or a spreadsheet line that the money never leaves - because commingled 'savings' gets spent.
Frequently asked questions
What is the difference between a sinking fund and an emergency fund?
Surprise: an emergency fund covers what you cannot predict - job loss, a hospital, a transmission on a Tuesday. A sinking fund covers what you absolutely can predict - holidays, insurance premiums, car registration, the phone that upgrades every three years. The emergency fund stays untouched; the sinking funds get spent exactly as planned, which is what keeps the emergency fund from becoming the holiday fund.
What expenses deserve a sinking fund?
Anything annual or irregular that you know is coming: holidays and gifts, car repairs and registration, insurance premiums if paid annually, home maintenance, vet visits, school costs, and the technology replacement cycle. The test is not size but predictability - a $600 expense you can name six months out deserves a $100 line, whatever it is.
Should a sinking fund earn interest?
For horizons under a couple of years, yield is a rounding error - the point is separation, not growth. A high-yield savings account per goal is the simple version; for horizons past three years, some run sinking funds inside conservative investments, but that imports risk into money with a date on it, which is exactly what a sinking fund exists to remove.
How many sinking funds is too many?
Past roughly eight lines, the bookkeeping overhead starts eating the benefit - every fund needs a transfer, a label and a monthly glance. The consolidation move: one 'irregulars' fund for the small predictable stuff (car tabs, vet, gifts) at an averaged number, with named funds only for the big single-purpose goals like the holidays or the roof.