Why budgets break
A monthly budget rarely fails on rent or groceries. It fails on the car registration, the semiannual insurance premium, the wedding in another state and December. These costs are entirely predictable, yet they land on a credit card or come out of the emergency fund because no month was ever assigned to pay for them. A sinking fund turns a lumpy annual cost into a flat monthly one. It differs from an emergency fund in kind. The emergency fund covers the unknown, while a sinking fund covers a known bill, or a known category such as car repairs where only the timing is uncertain.
Finding yours
Read through twelve months of bank and card statements and mark every charge that does not recur monthly. Most lists include the following.
- Car costs include insurance premiums, registration, and maintenance, which runs about $1,000 a year on an older car.
- Gifts cover the holidays, birthdays and weddings.
- Annual charges include subscriptions, memberships and professional dues.
- Health costs include the dental visit, new glasses, the insurance deductible and the veterinarian.
- Replacement costs cover devices, figured as price divided by lifespan, so a $1,200 laptop kept four years costs $25 a month.
The arithmetic
Suppose the year holds $1,200 of car insurance, $900 of car maintenance, $800 of gifts, $1,500 of travel, $300 of annual subscriptions and $300 of vet bills. The total is $5,000, which is about $417 a month, or $208 from each of two monthly paychecks. When you start in the middle of a cycle, fund the nearest deadline first. A $600 premium due in four months needs $150 a month until it is paid and $100 a month afterward. If the full figure is more than you can manage, begin with the bills that have fixed dates and add the softer categories later.
Where to keep it
Hold the money in a high-yield savings account and not in checking, preferably with sub-accounts named for each purpose. A single account with a small spreadsheet recording each fund's share works too. Schedule the transfer for the day after payday. When a bill arrives, pay it, move the matching amount out of the fund on the same day, and carry on. Review the amounts once a year, since premiums rise and plans change.
Tip A funded sinking fund lets you pay annually, which is usually cheaper. Insurers often discount a premium paid in full, and an annual subscription commonly costs 15 to 20 percent less than twelve monthly charges.
