HDB Sale of Balance Flats (SBF): How It Works, the 2026 Application Rates and How It Compares With BTO

HDB runs three modes of sale for new flats: Build-To-Order (BTO), Sale of Balance Flats (SBF) and open booking. In HDB's words, an SBF exercise "offers balance flats from earlier BTO exercises, surplus Selective En bloc Redevelopment Scheme (SERS) replacement flats, repurchased flats, etc." (HDB, Modes of Sale).

SBF flats are sold by HDB through the same new-flat process as a BTO, so an SBF flat is not a resale purchase. The difference is timing: a BTO flat is bought before it is built, while an SBF flat is further along, and about one in five of February 2026's was already finished.

A BTO sells you a flat that will be built. An SBF sells you one that is further along.

Recent SBF exercises have run alongside a BTO launch rather than on a fixed calendar:

HDB called the 2025 total of more than 10,200 SBF flats "the largest annual supply of SBF flats since 2016" (HDB, July 2025). It usually trails an SBF in an earlier release: the February 2026 exercise was first mentioned in October 2025, at about 3,000 flats, and launched with 4,320. No HDB release since 4 February 2026 has trailed another. Even at launch, HDB's February 2026 release described the SBF flats only as "located islandwide"; the details of each flat appear on the Flat Portal during the exercise.

For the February 2026 exercise, HDB scheduled SBF queue positions for April 2026 and flat bookings to start, tentatively, from July 2026. HDB posts the number of applications received, and each applicant's status and results, on the HDB Flat Portal. To hear about the next SBF first, subscribe to HDB's e-Alerts, and have a valid HFE letter ready: the February 2026 application window was eight days.

Get the paperwork done in the quiet months. The last window was eight days.

HDB publishes the flats and applications for every town and flat type in each SBF exercise. Adding up its February 2026 table:

Source: HDB, flat supply and applications received, February 2026 SBF, as at 11:59pm on 11 February 2026 (HDB). Totals and "applications per flat" are PropKaki's arithmetic; HDB does not publish an overall SBF rate.

"Applications per flat" is not HDB's application rate. HDB computes its rate separately for each household type, as applications from that type divided by the flats set aside for it, and a higher rate means worse chances. On HDB's measure, the median first-timer family rate for 3-room and bigger SBF flats was 4.1 in February 2026, against 2.0 in July 2025. The two exercises offered different mixes of flats, so read that as a shift in the typical row, not a like-for-like change.

For 2-room Flexi flats the split by household is stark: HDB's median rate for seniors was 14.5, and for first-timer families 0.3.

The headline number hides the real one: your odds are set by your household type, town and flat type.

4-room flats were the biggest category in the exercise. HDB's figures for all 22 towns that offered them, hardest first:

Source: HDB, February 2026 SBF application rates, as at 11:59pm on 11 February 2026. "Launched before Oct 2024" is HDB's "Not Applicable" class: older non-PLH flats, which follow the Standard quotas.

For a 4-room in February 2026, the rate ran from 0.7 to 14.7 depending on the town.

We split HDB's February 2026 table for 3-room and bigger flats by whether each town-and-type row included Prime flats:

The eight Prime rows were in Queenstown, Bukit Merah, Kallang/Whampoa and the Central Area, and each mixed Prime flats with older ones. Under HDB's classification framework, Prime and Plus flats come with a 10-year minimum occupation period, cannot be rented out whole and carry a subsidy recovery when sold (HDB, Standard, Plus and Prime), so check each flat's terms on the Flat Portal before you apply.

Outside those eight rows, the size of the batch told you nothing:

Source: HDB, February 2026 SBF application rates; grouping by PropKaki. Across these 48 rows the rank correlation between batch size and rate was -0.07, effectively none; across all 56 rows it was -0.40, driven by the Prime rows.

The hardest rows were small batches of 4-rooms in Sengkang (14.7), Serangoon (10.8) and Pasir Ris (10.0), but the easiest row outside Prime was a small batch too: 21 flats of 5-room/3Gen in Bukit Batok, at 0.8.

HDB's own advice: "There is often strong interest in SBF flats, and the chances of getting a flat may be slim. For a better chance to secure a flat, please apply for a BTO flat with lower application rates, such as those with an application rate of around 1 or lower" (HDB, Modes of Sale).

Batch size told you nothing. Prime status told you a lot.

Sources: HDB Modes of Sale page; February 2026 release; sales-exercise FAQ; 23 August 2026 release. Verify on hdb.gov.sg.

On price, HDB publishes starting prices for each SBF exercise. For February 2026:

Source: HDB, February 2026 release, Table 4. HDB rounds prices up to the nearest thousand dollars. The after-EHG prices assume an Enhanced CPF Housing Grant of $120,000 (CCA and 2-room Flexi), $105,000 (3-room), $80,000 (4-room) or $55,000 (5-room and 3Gen), and none for Executive flats; your own grant depends on your income and eligibility. Where the grant would exceed 95% of the price, buyers still pay 5% in CPF or cash, which is why the CCA and 2-room Flexi rows do not fall to zero. CCA prices include senior-friendly fittings but not the mandatory Basic Service Package.

These are the cheapest flats of each type, not typical ones. Some SBF flats are sold on a remaining lease rather than a fresh 99 years, so check each block's lease on the Flat Portal, where the full price list only appears during the exercise.

SBF is about time: the flat is further along. The ballot is still a ballot.

The steps, as HDB set them out for February 2026:

1. Hold a valid HFE letter before you submit the application. HDB suspends new HFE applications during the exercise's application period, so this has to be done beforehand (our HFE guide).
2. Browse the flats on the Flat Portal. Details of SBF flats "will only be made available via HDB Flat Portal during the sales exercise".
3. Apply for one town and one flat type, online, with a $10 administrative fee. In an exercise that has both, you choose BTO or SBF, not both. For SBF, 5-room, 3Gen and Executive flats are grouped as one category.
4. The ballot. HDB shortlists by computer ballot, "not on a first-come, first-served basis", and may shortlist up to 200% of the supply so that later queue numbers can book if earlier ones drop out.
5. Queue position and booking. For February 2026, HDB said it would tell SBF applicants their queue positions in April 2026 and tentatively start bookings from July 2026. The option fee at booking was $500 for a CCA or 2-room Flexi, $1,000 for a 3-room and $2,000 for a 4-room or bigger. Results and application status are on the Flat Portal.
6. Keys. A completed flat: sign the Agreement for Lease, pay in full and collect the keys. A flat still being built: pay the downpayment, sign the Agreement for Lease, and collect the keys on completion.

Two rules matter once you have a queue number (HDB, Application):

• If your queue position is within the flat supply, you cannot apply in later BTO or SBF exercises until after your booking appointment.
• If you are invited to book and do not, when flats are available, you incur a non-selection count and HDB cancels all your ongoing flat applications. First-timer families are then placed in the second-timer category for a year and lose any extra BTO ballot chances they had built up; first-timer singles and second-timer families cannot apply in any sales exercise for a year. HDB waives the count if you had five or fewer SBF flats to choose from.

Only apply for a flat you would actually book.

HDB splits every SBF exercise into quotas by household type (HDB, Modes of Sale):

Older non-PLH flats launched before October 2024 follow the Standard split; older PLH flats follow the Prime one. Before these splits, at least 40% of the 2-room Flexi supply goes to seniors, and where a town has fewer than 20 flats of a type (3-room and bigger), all of them go to first-timer families first.

The Third Child Priority Scheme, enhanced from the June 2026 exercise, allocates "up to 10% of BTO flats, and up to 10% of SBF flats" to families with at least three children or expecting a third (HDB, Priority Schemes).

Ballot chances then weight the draw: three for first-timer parents and married couples, two for other first-timer families, and one each for second-timer families, seniors and first-timer singles. From the February 2027 exercise, first-timer families with or expecting children will get one extra ballot chance for each Singapore Citizen child aged 18 and below, in BTO and SBF alike (HDB, 23 Aug 2026).

Priority schemes decide your quota; ballot chances decide your place in it.

HDB's third mode of sale exists for exactly this: "The open booking of flats offers unselected flats from past SBF exercises. Flat buyers can apply online and receive a queue number for flat booking on a first-come-first-served basis, and book a flat as early as the next working day, where possible" (HDB, Modes of Sale).

The catch is availability. HDB suspends open-booking applications before each new injection of flats and when every flat is taken, and the Flat Portal's landing page in mid-September 2026 read: "All the flats have been booked."

Open booking is where SBF leftovers go. In September 2026 it was empty.

If you miss out, the usual alternatives are another exercise or a resale flat. Here is what the resale market charged in the towns with the hardest February 2026 SBF odds:

Sources: HDB, February 2026 SBF application rates; PropKaki analysis of HDB resale registrations, January to June 2026. Resale medians cover every flat of that type in the town and are gross of fees; they are not the price of the SBF flats.

HDB describes the gap in its own words: "Like BTO flats, the SBF flats are heavily subsidised and priced considerably lower than comparable resale flats" (HDB, July 2025). On the resale side, first-timers may qualify for CPF housing grants for resale flats, which narrow the difference; see our guide to HDB housing grants. A resale purchase also needs its own HFE letter. To see what a resale flat would mean for your cash and loan, run the numbers in the Property Financial Planner.

If you miss out, compare the resale price after the grants you would get, not before.

Official figures. Flat supply, applications and application rates are HDB's, from its published table for the February 2026 SBF exercise (final as at 11:59pm on 11 February 2026) and the July 2025 table. Flat counts, starting prices, rules and quotas come from HDB's February 2026 release and its Annex B, the July 2025, October 2024, October 2025, June 2026 and 23 August 2026 releases, and HDB's Modes of Sale, Application, Priority Schemes, Standard/Plus/Prime and sales-exercise FAQ pages and the Flat Portal, read in September 2026. HDB's median rates (4.1, 2.0, 14.5 and 0.3) are quoted as HDB published them.

Our analysis. Category totals, "applications per flat", the split between rows that include Prime flats and all other rows, the batch-size grouping and its rank correlation are PropKaki's arithmetic on HDB's rows. Resale medians are PropKaki's analysis of HDB resale registrations for January to June 2026, the latest half-year with a complete sample. How we compute figures across the site: PropKaki methodology.

What we have not claimed: that SBF is cheaper or dearer than BTO (HDB does not say); when the next SBF will be (HDB had not announced one as at 18 September 2026); why particular rows drew more applicants; or your chances in a future exercise, which depend on the flats offered and who applies. This is a practical explainer, not legal or financial advice; check hdb.gov.sg before you rely on it.