Some expenses are not emergencies at all. The car insurance renews every year. School fees arrive every term. Holidays, festivals and family weddings come round on a calendar. Yet these "surprises" are one of the main reasons people dip into savings or go into debt.
A sinking fund is the fix: a small, separate pot where you save a little each month for one known future cost, so the money is ready when the bill arrives.
Sinking fund vs emergency fund
| Sinking fund | Emergency fund | |
|---|---|---|
| Purpose | A known cost with a date | Unexpected events |
| Examples | Insurance, school fees, holiday, new phone | Job loss, medical bill, urgent repair |
| Do you spend it? | Yes, that is the plan | Only in a real emergency |
| How many? | One per goal | Usually one |
Keeping them separate protects your emergency fund. If the holiday money and the emergency money are in one pile, the holiday wins every time.
The goal math
Every sinking fund needs two numbers: how much, and by when.
monthly amount = (target − already saved) ÷ months left
Example 1, yearly insurance. A $900 policy renews in 12 months: $900 ÷ 12 = $75 a month. When the renewal comes, the money is sitting there.
Example 2, a holiday. You want $2,400 for a trip in 8 months and already have $600 set aside: ($2,400 − $600) ÷ 8 = $225 a month.
Example 3, school fees. $1,500 due in 10 months, starting from zero: $150 a month, or about $35 a week if you are paid weekly.
Common sinking funds
- Car insurance, registration and servicing
- School fees, uniforms and books
- Holidays and trips home
- Festivals, gifts and family celebrations
- Annual subscriptions and memberships
- A new phone or laptop
- Medical and dental costs you can predict
Start with the two or three that hurt most when they arrive. You can add more later.
A percentage of every income
If your income changes, a fixed monthly amount can be hard to keep. An alternative is to send a percentage of every income to a pot, for example 10% of each salary or each freelance payment. The goal is reached faster in good months and you never commit to more than you have. This is often called "paying yourself first".
Where to keep the money
Some people open a separate bank account per goal; others keep one savings account and track the pots separately. Both work. What matters is that you can see each pot's balance, so you know the holiday money is not the insurance money.
A tracking app does not need to hold your money to help. In RatePocket, savings pockets only record what you set aside (the money stays in your bank, your wallet or wherever you keep it). You can give a pocket a goal and a date, and the app shows how much to save each month to get there.
Moving money between pots
Plans change. If the trip is cancelled, move that money to another goal instead of spending it. Moving between pots does not change your total savings; it only changes what each part is for. Write the move down so you remember why.
Use the leftovers
At the end of each month or pay period, look at what is left of your spending budget. Instead of letting it disappear into next month, move some or all of it into a sinking fund. Small leftovers add up surprisingly fast: $40 a month is $480 a year.
Common mistakes
- Too many pots at once. Ten pots of $10 each feel like nothing. Start with a few that matter.
- No date. A goal without a date has no monthly amount, so it never gets funded.
- Borrowing from one pot for another without writing it down. You will forget.
Find the monthly amount for your own goal.
Open the savings goal calculatorKey takeaways
- A sinking fund saves for one known cost with a date; it is not your emergency fund.
- Monthly amount = (target − already saved) ÷ months left.
- Start with the two or three costs that hurt most when they arrive.
- Send month-end leftovers into a pot instead of letting them vanish.
This guide is general information to help you organise your money. It is not financial, tax or legal advice for your situation. Found a mistake? Tell us and we will fix it.