Most budgets are destroyed by costs that were never a surprise.
Car insurance renews every year. Christmas happens in December. Your laptop will need replacing. None of these are emergencies, but if you budget month to month, every one of them arrives as a shock that goes on a credit card.
A sinking fund fixes this. You divide the known cost by the months until it’s due and save that amount every month. When the bill lands, the money is already there.
How Sinking Funds Work in Spendly
Create a fund with a target amount and the date you need it by. Spendly works out the monthly contribution, tracks what you’ve put in, and tells you whether you’re on pace.
- Target and date: “£620 for car insurance by March”
- Monthly contribution calculated from what’s left and how long you’ve got
- On-pace tracking so you know in November whether December is going to hurt
- Settle the fund when the bill actually arrives, the money goes out, and the fund resets for next year
- Its own currency per fund, so a fund for a bill in another country stays denominated in that country’s currency
The Settle Step
Settling a fund records the payout when the bill arrives, clears the balance and lets you set the next target. It is the part most sinking fund trackers miss: saving for the bill is only half the cycle, and you also have to spend it and start again.
When your insurance renews, you settle the fund in Spendly. It records the payout, clears the balance, and you set the next target. The fund is a loop, not a one-off, because the cost is a loop.
Without that step you end up with a spreadsheet full of funds that were completed once in 2024 and never reset, which is how most people quietly abandon the method.
Sinking Funds vs Savings Goals
They look similar and Spendly has both, because they’re not the same thing.
| Sinking fund | Savings goal | |
|---|---|---|
| What it’s for | A cost you know is coming | Something you want |
| Recurring? | Yes, it resets and runs again | No, you finish it |
| If you don’t fund it | The bill still arrives | Nothing happens, you just don’t get the thing |
| Examples | Insurance, road tax, Christmas, service charge | House deposit, a trip, an emergency fund |
The practical difference: missing a savings goal is a disappointment, missing a sinking fund is a debt.
What People Actually Use Them For
The list is more boring than budgeting content usually admits, and that’s the point:
- Annual insurance: car, home, travel, pet
- Vehicle costs: road tax, MOT, servicing, tyres
- Christmas and birthdays: the single most common cause of January credit card debt
- Replacing things that will break: laptop, phone, washing machine, boiler
- Property: service charges, ground rent, a share of the roof
- Professional: subscriptions, registration fees, annual software renewals
- Travel: flights home and visa renewals if you live abroad
For Expats and Cross-Border Life
If you live in one country and still have obligations in another, sinking funds get harder in a way most trackers ignore.
A visa renewal fee, an annual flight home, or a property charge in your home country is denominated in that currency, but you’re saving out of income in a different one. If you track the fund in your home currency, exchange rate moves quietly wreck your plan.
Spendly holds each fund in its own currency. Save toward a €900 charge as a €900 charge, and let the base-currency view handle the conversion for your overall picture rather than the other way round.
See how multi-currency support works, or read about setting financial goals that stick.
Common questions
What is a sinking fund?
A sinking fund is money set aside monthly for a known, irregular cost such as annual insurance, road tax or Christmas. You divide the cost by the months until it is due and save that amount each month, so the money is already there when the bill lands.
How is a sinking fund different from a savings goal?
A sinking fund is for a cost you know is coming and it recurs, resetting after each bill. A savings goal is for something you want and it finishes. The practical difference: missing a savings goal is a disappointment, missing a sinking fund is a debt.
What does settling a fund do?
Settling records the payout when the bill actually arrives, clears the balance and lets you set the next target. It matters because the cost is a loop, not a one-off. Without that step you end up with funds that were completed once and never reset.