Sinking fund

Before you rely on it

What to check

Base the monthly figure on a current replacement cost and a realistic remaining life.

The common error

Where people go wrong with sinking fund

Setting the contribution once and never revisiting it. Replacement costs move, and a fund sized against a five-year-old quote arrives short.

Worked through

Sinking fund in plain numbers

You expect a $12,000 roof replacement in five years. Saving in an account earning 3% a year, compounded monthly, the monthly deposit that reaches $12,000 is about $185.62. Over sixty months you deposit $11,137 and interest adds about $863. Without interest you would need $200 a month; the same idea works for a company setting money aside to retire a bond, or a condo association funding future repairs; a sinking fund turns one big future bill into a small steady payment, so the day the bill arrives is uneventful rather than a crisis.

Easily confused

Sinking fund and its neighbours

A sinking fund is not an emergency fund or a savings goal for something you might want; it is set aside for a known future expense with a known date and rough amount. An emergency fund covers unpredictable events. A reserve fund in a condominium is a sinking fund for building components. In corporate finance a sinking fund also means money set aside to repay debt at maturity, sometimes required by the bond terms; the common feature is regular deposits toward a defined obligation.

In real decisions

Where sinking fund turns up

Households use sinking funds for car replacement, property taxes, annual insurance premiums, holidays and home repairs; businesses use them for equipment replacement and debt repayment. Homeowner and condo associations use them for roofs, elevators and paving; a calculator takes the target, the date and the interest rate and returns the periodic deposit. Keeping the money in a separate account makes the purpose clear and prevents accidental spending.

Know the edges

Where sinking fund stops being reliable

Costs may rise with inflation, so the target should include a cushion. Interest rates change. If the date moves, the amount per period changes. Underfunding is common when targets are guesses. Review estimates each year and adjust deposits. Keep the funds in safe, accessible accounts if the date is near.

Quick answers

What people ask about sinking fund

How much should I save each month? Divide the target by the number of months, then reduce the amount slightly if the account earns interest. A calculator can compute the exact deposit.

Should I keep a sinking fund in a separate account? Yes. A separate account or labeled bucket makes the purpose clear and reduces the temptation to spend it.

What if the cost rises? Add a cushion for inflation when setting the target, and review yearly. Adjust deposits if estimates change.

Where should I keep the money? In a safe account with easy access, such as a savings account or short-term certificates that mature when needed. Avoid volatile investments for near-term goals.

Is it better than borrowing later? Saving avoids interest and gives choice, but it requires discipline and ties up money. Borrowing may make sense when returns elsewhere exceed the loan cost.