Sinking funds explained (with examples)

What is a sinking fund?

A sinking fund is money you save in small, regular amounts for one specific cost that you know is coming. Instead of finding £600 in one go when your car insurance renews, you put £50 aside each month for a year. When the bill arrives, the money is already there.

The name comes from business and government finance, where a "sinking fund" is money set aside to pay off a debt or replace equipment. For a household it means the same thing on a smaller scale: you sink a little money into a pot each month so a big cost later doesn't sink you.

Sinking funds at a glance

Here is how the monthly amount works for a few common costs. These are worked examples, not typical prices; use your own bills.

The rule behind every row is the same: the total cost, minus anything you have already saved, divided by the months left until you pay it.

Sinking fund vs emergency fund

People often mix these up, but they do different jobs.

• An emergency fund is for things you can't predict: losing your job, an urgent boiler or furnace repair, a vet bill, a sudden trip home. You hope never to use it, and you keep it topped up. Our emergency fund guide explains how big it should be.
• A sinking fund is for things you know will happen. You plan to spend it, on a date you roughly know, for a purpose you have already chosen.

Keeping them separate matters. If your car insurance comes out of your emergency fund every year, the emergency fund is quietly shrinking, and it may not be there when a real emergency hits. Sinking funds protect your emergency fund by catching the predictable costs first.

What about sinking funds vs a general savings pot?

A general savings pot is money with no job yet. A sinking fund has a label, a target and a date. That label is what makes it work: it is much harder to dip into "car insurance, due March" for a takeaway than into a pot called "savings".

How to set up a sinking fund in five steps

1. List your irregular costs. Go through the last 12 months of bank and card statements and write down every cost that didn't happen monthly. Typical ones: car insurance, MOT or vehicle inspection, servicing, registration or road tax, home or contents insurance, the TV licence, school trips and uniforms, glasses and dental work, annual subscriptions, birthdays, religious and seasonal festivals, holidays, and home repairs.
2. Put a number and a date on each. Use last year's bill plus a little extra if prices have risen. If you don't know the exact date, use the month.
3. Work out the monthly amount. Divide what you still need by the number of months left. If a bill is due soon and you can't cover the full monthly amount, save what you can now and plan to pay the rest from that month's income.
4. Choose where the money lives. A separate easy-access savings account is ideal, so the money is out of sight but still reachable. Many banks and apps let you create named pots or "spaces" inside one account, which is perfect for several sinking funds.
5. Automate it. Set a standing order or automatic transfer for the day after payday. Saving first, before you start spending, is far easier than saving whatever is left.

You can also add your yearly costs to the SpendMath calculator. It spreads once-a-year costs into monthly amounts, so you can see the true monthly cost of your household next to everything else.

Worked example: a year of sinking funds

Here is one household's plan in the UK. The figures are an example, built from this family's own bills, not averages.

• Car insurance: £540 due in March. 12 months away, so £45 a month.
• Car service and MOT: £300 due in June. £25 a month.
• Summer holiday: £1,200 in August. Starting in November, that is nine months: about £133 a month.
• Christmas presents and food: £480 in December. £40 a month.
• School uniforms and shoes: £240 in August. £20 a month for 12 months.

Total: about £263 a month. That sounds like a lot. But this family was already spending this money every year; it just arrived in painful lumps. Seeing the real number lets them decide calmly. They might choose a cheaper holiday, shop around for insurance, or spread present buying across the year.

The same idea in dollars

A household in the US might plan $1,500 for holiday travel in December, $720 for car insurance paid every six months ($120 a month), and $360 for back-to-school costs in August ($30 a month). In Canada, add winter tyres and the annual car registration. In Australia, add car rego and green slip renewal, and any school levies. The maths is the same everywhere: total, divided by months left.

Starting late

If a bill is only three months away and you have nothing saved, the monthly amount will be high. You have three options: save the full amount and cut back elsewhere for a while; save what you can and pay the rest from that month's income; or, for things like holidays, change the plan to fit what you can save. Next year, start 12 months ahead and the monthly amount drops.

Tips that make sinking funds work

• Start with your two or three biggest irregular costs. You don't need 15 pots on day one. Insurance and holidays alone often fix most of the pain.
• Round up. Saving £50 instead of £45 builds a small cushion for price rises.
• Keep a simple list. A note on your phone with each fund, its target, its due date and its balance is enough.
• Don't raid one fund for another without a plan. If you move money from the holiday pot to cover a bigger car repair, write down how you will refill it.
• Combine small ones. Lots of small annual subscriptions can share one "renewals" pot.
• Review twice a year. Prices change, and so do plans. Adjust the monthly amounts when they do.
• If money is very tight, start tiny. Even £10 or $10 a month into a "next big bill" pot is better than nothing, and it builds the habit.

Sinking funds work well alongside the 50/30/20 rule: the monthly amounts for essential irregular costs, such as insurance, belong with your needs, while holidays and gifts sit in your wants.

Saving for a wedding, Hajj or Umrah in Pakistan? Our guide on how to save for a wedding, Hajj or Umrah works through the numbers in rupees.

Frequently asked questions

Related guides

• How much should you have in an emergency fund?
• The 50/30/20 rule explained, with worked examples
• How to save money on irregular income (even when it's low)

Sources

• MoneyHelper (UK government-backed): Managing your money using savings pots
• Consumer Financial Protection Bureau: Assess your spending
• Moneysmart (Australian Government, ASIC): How to do a budget