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CPF Accrued Interest Explained

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The 2.5% compound mechanism

Every dollar of CPF OA used for housing is treated as an opportunity-cost withdrawal from your retirement. CPF Board imputes the foregone interest at the OA floor rate (2.5% p.a., compounded monthly) for every month the CPF is "outside" the OA. The cumulative imputed interest is your accrued interest (AI).

On sale of the property, the total CPF refund into your OA is principal + AI. This refund occurs before any cash proceeds are paid out to you.

Accrued interest growth over time

For a single lump-sum of $1 CPF used at the start, the accrued interest after N years (monthly compounding at 2.5%):

Years heldRefund factorAI per $100K used
51.133$13,294
101.284$28,386
151.455$45,524
201.649$64,978
251.869$87,039
302.119$111,872

The actual AI depends on the timing of each CPF dollar used (downpayment vs spread-out monthly use), not just the total. The above is for a single lump-sum case.

A typical homeowner's AI profile

A more realistic example: borrower uses $80,000 CPF for downpayment in year 0, then uses CPF for monthly mortgage instalments of $3,000/month (mix of principal and interest, with CPF covering the full instalment) for 25 years. Total CPF used ≈ $980,000 (principal). AI on sale at year 25 ≈ $300,000 to $400,000 depending on instalment composition.

Total CPF refund on sale = $980,000 + ~$350,000 AI = ~$1,330,000 to be returned to the seller's OA before any cash is released.

The "negative sale" scenario

Sometimes the sale price (minus the outstanding mortgage) is not enough to refund the full CPF principal + AI. This is a negative sale. Example:

  • Sale price: $1.4M
  • Outstanding mortgage to bank: $700K
  • Net proceeds after mortgage: $700K
  • CPF refund needed: $980K (principal) + $350K (AI) = $1.33M
  • Shortfall: $1.33M − $700K = $630K

CPF Board generally waivesthe shortfall if the seller is buying a replacement home and applies the available CPF refund towards it. The seller doesn't personally owe the shortfall to CPF as a debt — but the "notional" AI lost is a real loss of retirement adequacy. For sellers not buying a replacement, the treatment depends on circumstances.

Voluntary refunds

Owners can voluntarily refund CPF back to their OA at any time, stopping further accrued interest on the refunded portion. This is a popular move for owners with long ownership horizons who want to:

  • Pay down their "CPF debt" to reduce the eventual refund obligation on sale
  • Reset the CPF balance to earn the OA interest again
  • Avoid CPF use running out before the mortgage is paid off

Related guides

Frequently asked questions

What is CPF accrued interest?▾

When you use CPF Ordinary Account (OA) money to pay for property, you are effectively borrowing from your future retirement. CPF Board treats this as if you had kept the money in your OA earning 2.5% interest. The interest you 'would have earned' accumulates over the years and is the 'accrued interest' (AI). On sale of the property, you must refund the principal CPF used PLUS the accrued interest back into your OA.

What rate is used — 2.5% or something higher?▾

2.5% per annum, compounded. This is the CPF OA floor rate, reviewed quarterly but consistently at this floor for many years. CPF Board uses 2.5% even when higher OA rates briefly applied due to enhanced interest tiers — the AI computation uses the basic floor rate.

How is accrued interest compounded — monthly or annually?▾

Monthly. Each month, the accumulated principal + AI to date earns 2.5% / 12 = ~0.208% for that month. This is added to the AI balance the following month. Over many years the compounding effect is significant — over 25 years, a single $1 of principal grows to about $1.87 (87% accrued interest).

What happens if the sale price isn't enough to refund CPF?▾

This is called a 'negative sale.' The order of priority on sale is: (1) outstanding mortgage, (2) CPF refund (principal + AI), (3) cash to seller. If proceeds after step (1) are less than the CPF refund needed, the shortfall is waived BY CPF Board provided the seller is buying another property and the unrefunded amount goes into the new property. Otherwise the shortfall may be recoverable from the seller's other CPF accounts in some cases.

Can I voluntarily refund CPF early to stop accruing interest?▾

Yes. Voluntary refunds can be made at any time and stop further accrued interest on the refunded portion. This is sometimes done by sellers who anticipate a long ownership horizon — paying down the 'CPF debt' early to reduce the eventual refund obligation on sale. The voluntary refund goes back to OA and earns the normal OA rate going forward.