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The short answer
A sinking fund is money you set aside each month for a bill you know is coming, so that when it falls due the cash is already there. Divide the bill by the months left: ₦1,200,000 rent due in ten months needs ₦120,000 a month. Unlike an emergency fund, each sinking fund has a named purpose and a date.
What a sinking fund is, and is not
The term comes from company finance, where a firm sets money aside to repay a bond. For a household, it means one pot per known future bill. Nigerian households face many large, lumpy bills: annual or two-year rent paid upfront, school fees three times a year, vehicle papers, insurance premiums, festive travel, exam fees. When these are not saved for, they are paid with loans, salary advances or by raiding the emergency fund.
A sinking fund is not an emergency fund. The emergency fund covers things you cannot predict: illness, job loss, a burst pipe. A sinking fund covers things you can, even if the exact amount moves a little. Keeping them separate stops a planned bill from being treated as an emergency.
How to calculate each one
- List every bill above, say, ₦20,000 that comes less than monthly.
- Note the amount and the month it is due. Use last year's figure plus a margin for price rises.
- Count the months between now and the due date.
- Divide the amount by the months. That is your monthly contribution.
- After you pay the bill, restart the fund for the next cycle, now over a full period.
Price rises matter. The NBS put headline inflation at 14.63% year on year for September 2026, and rent and school fees often rise faster than the average. Adding 10% to 15% to last year's bill is a reasonable starting margin; ask the landlord or school early if you can.
A labelled household example
Example only. Amounts are illustrative except where a published price is cited.
| Bill | Amount | Months to save | Monthly contribution |
|---|---|---|---|
| Annual rent | ₦1,200,000 | 10 | ₦120,000 |
| School fees, 3 terms of ₦180,000 | ₦540,000 a year | 12 | ₦45,000 |
| Health plan (Reliance Health Red Beryl, annual individual) | ₦68,400 | 12 | ₦5,700 |
| WAEC/NECO SSCE fee for one candidate | ₦50,000 | 10 | ₦5,000 |
| Total | ₦175,700 |
Sources for the published figures: Reliance Health's group plans page, updated 16 October 2026, lists Red Beryl at ₦68,400 a year per individual (group plans need at least three principals). BusinessDay reported in July 2026 that the WAEC and NECO SSCE fee rises to ₦50,000 per candidate, applying from NECO's 2027 internal examination. Check current prices before you plan.
The total shows why sinking funds matter: ₦175,700 a month is a large commitment, but paying ₦1,200,000 of rent in one go without saving ahead would be harder still. If the total is too much, you have learnt something important early: you may need cheaper housing, a different school or a payment plan.
Other bills worth a fund
- Vehicle papers and insurance. The Lagos MVAA price list (as at June 2025) puts a private vehicle licence for a 1.6 to 2.0 litre engine at ₦1,875, with insurance and other papers on top.
- Festive travel and gifts. December and Sallah costs come every year.
- Gadgets. Phones and laptops wear out; saving a small amount monthly avoids buying on expensive credit.
- Family obligations. Weddings, naming ceremonies and burials in the extended family are frequent, if not exactly dated.
- Annual subscriptions and dues. Professional bodies, associations, software.
When the bill comes early or grows
Landlords sometimes raise rent at renewal, and schools add levies mid-session. Two habits protect you. First, ask early: three or four months before renewal, ask the landlord or bursar what next year's figure will be, and adjust the monthly contribution. Second, keep a small top-up pot shared across all sinking funds, for example ₦10,000 a month, to absorb surprises without breaking the emergency fund.
If a bill falls due before the fund is full, pay what you have and negotiate the rest. Many schools accept instalments if you ask before resumption, and some landlords accept part-payment from a known tenant. Borrowing to close a small gap is far cheaper than borrowing the whole bill.
Finally, once a fund has done its job, celebrate briefly and restart it the following month. The second year is easier: the monthly amount is already part of your budget, and you know the real figure.
Where to keep sinking funds
Each fund needs to be reachable on its due date and hard to spend before then. A locked savings plan with a maturity date a week before the bill is ideal. Cowrywise's help centre, for example, describes Regular Savings plans that cannot be withdrawn before maturity and have a minimum duration of three months; check the rules of whichever product you use. Short funds, under three months, are better in a separate savings account.
Name each pot after its bill. 'Rent 2027' is harder to raid than 'Savings 2'.
Where Pryme fits
Pryme's Savings Boxes let you open one Fixed Box per bill, each locked until its due date, and a Flexible Box for small, less certain costs. A Personal Assistant can prepare each monthly contribution and remind you before due dates; you approve each transfer. For fees in detail, see saving for school fees term by term.
Questions people ask
What is a sinking fund in personal finance?
Money saved monthly towards a specific bill you know is coming, such as rent or school fees, so the cash is ready on the due date.
Is a sinking fund the same as an emergency fund?
No. A sinking fund is for known, dated bills; an emergency fund is for costs you cannot predict.
How do I save for yearly rent in Nigeria?
Divide the expected rent by the months until it is due and save that amount monthly in a locked plan. ₦1,200,000 due in ten months needs ₦120,000 a month.
How many sinking funds should I have?
One for each large, regular bill. Most households need between three and six.
Sources
- Voice of Nigeria: Nigeria's headline inflation drops to 14.63 per cent (NBS September 2026 CPI, 16 Oct 2026) · accessed Oct 2026
- Reliance Health: group health plans and prices (page updated 16 Oct 2026) · accessed Oct 2026
- BusinessDay: FG approves 82% increase in WAEC, NECO examination fee to N50,000 (12 Jul 2026) · accessed Oct 2026
- Lagos MVAA: products, process and prices (as at June 2025, PDF) · accessed Oct 2026
- Cowrywise Help: Types of savings plans on Cowrywise · accessed Oct 2026
This article is general information, not financial, legal or tax advice. Products described are provided under the terms on this site and are subject to regulation and eligibility.