Published 5 November 2026. By Cheng Xu, BTO Radar.
Getting a BTO queue number larger than the number of flats offered — such as queue number 145 out of 100 flats (145% of supply) — does not automatically mean you missed out. Because a substantial fraction of invited applicants decline to book a flat, HDB issues queue numbers up to 300% of the flat supply and invites applicants subject to availability and ethnic quota (HDB booking rules).
Why roughly 40% of invited BTO applicants do not book
HDB has publicly reported that around 40% of applicants invited to book a flat eventually decline to do so (HDB, March 2023). This historical figure predates the October 2023 non-selection changes and is not a current forecast. Possible reasons for declining include:
- Remaining units do not fit the buyer's budget or floor preference: Low-floor units, units near bin centres or substations, or higher-priced stacks may be all that remain when later queue numbers are called.
- HFE letter or financing gaps: Buyers discover at the selection appointment that their HDB Flat Eligibility (HFE) loan amount or EHG grant is smaller than expected.
- Change of plans: Some households buy a resale flat during the waiting period between balloting and flat selection.
How far past 100% can a queue number still book a flat?
If a project has U units and an average decline rate of d among invited applicants, then inviting Q applicants yields approximately Q × (1 − d) bookings. For all U units to be taken, the queue reaches approximately Q = U ÷ (1 − d):
| Share of invited applicants who decline (d) | Expected queue cutoff as % of flat supply | Example: 400-unit 4-room pool reaches queue number | Invitation probability at rate 3.0 (equal weights) |
|---|---|---|---|
| 0% (nobody declines) | 100% of supply | #400 | 33.3% (reproduce) |
| 20% decline | 125% of supply | #500 | 41.7% (reproduce) |
| 30% decline | 143% of supply | #571 | 47.6% (reproduce) |
| 40% decline (historical illustration) | 167% of supply | #667 | 55.6% (reproduce) |
| 50% decline (hypothetical) | 200% of supply | #800 | 66.7% (reproduce) |
You can test any application rate and decline assumption directly in the BTO ballot chance calculator.
The non-selection penalty: why fewer people drop out carelessly now
Since the October 2023 BTO exercise, HDB tightened the rules on declining to book a flat (HDB October 2023 administrative details):
- First non-selection: If you are invited to book a flat and do not select one, first-timer applicants lose their first-timer priority (and extra ballot chances) for one year and are treated as second-timers in BTO/SBF ballots during that year.
- Exception for very few remaining units: HDB waives the non-selection count when there are 10 or fewer BTO flats (or 5 or fewer SBF flats) left to choose from at your selection appointment.
- Cancelling after booking: If you book a flat (pay the Option Fee) and later cancel before or after signing the Agreement for Lease, you forfeit the Option Fee (or 5% of the flat price after signing) and face a one-year wait-out period before applying again.
Practical checklist if your queue number is between 100% and 200%
- Check the Ethnic Integration Policy (EIP) quota on the HDB Flat Portal: Even if units remain when your queue number approaches, you can only book if your household's ethnic group still has quota left in that block and project.
- Track the remaining unit count before your appointment: If 10 or fewer BTO units remain when your appointment starts, you can decline without incurring the one-year first-timer priority suspension.
- Prepare your cash and CPF numbers before selection day: Run the BTO downpayment & EHG calculator on the lowest- and highest-priced remaining units so you know immediately at the HDB Hub appointment which units fit your 30% MSR and CPF OA balance.
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