If there’s one concept I wish every HDB owner understood before they bought their flat — not when they’re selling it — it’s CPF accrued interest. It’s the quiet number that turns a “$200,000 profit” into “$80,000 in cash,” and it grows every single month you own your home.
It’s not a fee, it’s not a trick, and it’s entirely yours. But if you don’t account for it, you will badly overestimate the cash your upgrade frees up. Let me explain how it works and show you the actual compounding.
Pull your accrued interest from your CPF dashboard and the calculator does the rest, showing your true net cash position.
What accrued interest is
Your CPF Ordinary Account (OA) earns 2.5% per annum. The moment you use OA money for your flat — the downpayment, the monthly installments, the stamp duty — that money leaves your account and stops earning that 2.5%.
CPF’s rule is simple: when you sell, you must return to your OA not just the principal you withdrew, but the interest that principal would have earned if it had stayed put. That foregone interest is accrued interest. Refunding it restores your retirement savings to where they’d be if you’d never dipped in.
The key word is compound. Accrued interest is calculated at 2.5% compounded annually on the outstanding principal — so it grows faster the longer you hold the flat, and it never stops until you sell and refund.
The step-by-step calculation
Say you withdrew $200,000 from your OA in 2018 to buy your flat, and you’re selling in 2026 — eight years later. Accrued interest compounds at 2.5% each year:
| Year | Opening balance | + 2.5% accrued interest | Closing balance owed to CPF |
|---|---|---|---|
| 2018 | $200,000 | $5,000 | $205,000 |
| 2019 | $205,000 | $5,125 | $210,125 |
| 2020 | $210,125 | $5,253 | $215,378 |
| 2021 | $215,378 | $5,384 | $220,763 |
| 2022 | $220,763 | $5,519 | $226,282 |
| 2023 | $226,282 | $5,657 | $231,939 |
| 2024 | $231,939 | $5,798 | $237,737 |
| 2025 | $237,737 | $5,943 | $243,681 |
By 2026, that $200,000 principal has become roughly $243,700 owed back to your OA. The extra ~$43,700 is accrued interest — and notice it crosses $226,000 within the first five years alone. The longer you hold, the steeper it climbs, because each year’s interest earns interest the next year.
Why your “profit” isn’t your cash
Here’s the trap. An owner who bought at $450,000 and sells at $650,000 thinks: "$200,000 profit." But watch what the accrued interest does to the cash:
- Sale price: $650,000
- Less outstanding loan: −$150,000
- Less CPF refund (principal + accrued interest): −$243,700
- Less selling costs (commission + legal): −$16,000
- Cash in hand: ≈ $240,300
The CPF refund of $243,700 is still the owner’s money — but it’s now sitting in the OA, not the bank. The “profit” feeling and the spendable cash are simply different things. The full sale-proceeds breakdown, including how the CPF refund interacts with your loan redemption, is in How Much CPF Do You Get Back When Selling Your HDB?.
Does the refunded interest just disappear?
No — and this is the part that softens the blow. The accrued interest you refund goes straight back into your OA, where it resumes earning 2.5%. If you’re upgrading, that larger OA balance can be redeployed toward your condo’s CPF-eligible downpayment. You haven’t lost the money; you’ve moved it from “potential cash” back into “CPF savings.” The real impact is on liquidity — how much actual cash you have for the parts of the purchase CPF can’t cover (the 5% cash downpayment, BSD, and any ABSD float).
How to find your exact figure
Don’t guess from a formula — your real number is published for you. Log in to the CPF website → Home Ownership dashboard, and you’ll see your principal withdrawn, accrued interest to date, and the total refund due if you sold today. That’s the figure to plug into any upgrade calculation. Our calculator asks for it directly for exactly this reason — your statement beats any estimate.
The bottom line
CPF accrued interest is 2.5% compound interest on every OA dollar you put into your flat, refundable to your OA when you sell. It’s yours, but it lands in CPF, not cash — and because it compounds, the longer you’ve owned, the more it eats into your spendable proceeds. Account for it honestly and your upgrade numbers will hold up.
Net cash from your HDB sale, ABSD exposure, and the condo budget you can actually afford — worked out in about 2 minutes.
General information for Singapore HDB upgraders, not financial advice. The compounding table is illustrative; CPF computes accrued interest monthly on actual withdrawals. Check your CPF Home Ownership dashboard for your exact figures.