Sale of Balance Flats and Open Booking: The BTO Alternatives
How Sale of Balance Flats (SBF) and Open Booking work as alternatives to a BTO ballot — shorter waits, completed units, how selection differs, and the trade-offs.
SG Block Index · updated 2026-07-16 · data.gov.sg & OneMap
A BTO ballot is not the only way to buy a new flat from HDB — and for buyers who can’t wait four or five years for a project to be built, it may not be the best. The Sale of Balance Flats exercise and Open Booking offer leftover new flats, often much sooner, sometimes with keys ready. Here is how each works and when to choose them over a BTO.
What Sale of Balance Flats actually is
SBF gathers the flats that didn’t sell first time round: balance units from earlier BTO exercises, surplus replacement flats, and flats HDB has bought back. Because these projects are further along — many under construction, some already completed and ready for occupancy — the waiting time is far shorter than a fresh BTO, and in the best cases you can collect keys almost immediately. That speed is the whole appeal.
How it differs from a BTO
A BTO is a brand-new project launched across selected towns; you ballot for a queue number, and construction begins once enough units are booked, which is why the wait runs to several years. SBF, by contrast, is existing stock — less waiting, but you take what is left rather than the pick of a new development. Both use a computerised ballot to assign your queue position after the application window closes.
Open Booking: no ballot, first come first served
When flats remain unsold even after an SBF exercise, HDB releases them through Open Booking. Here there is no ballot at all: applicants receive a queue number and can book a flat as early as the next working day, where units are available. It is the fastest route to a new flat — the catch is that the remaining choice is thin, since the more desirable units are usually long gone.
The trade-off: speed versus choice
SBF and Open Booking trade selection for certainty. You give up the wide choice of a new launch and accept leftover stock — often in less sought-after stacks or locations — in return for a home you can move into far sooner and, frequently, view before you buy. Balloting for SBF in mature towns can still be competitive. And note that returned Plus or Primeflats carry their 10-year MOP and subsidy clawback even through SBF.
Eligibility and how to apply
The eligibility rules — citizenship, age, income ceilings, first-timer priority — mirror those for a BTO, so the same eligibility and schemesapply. In practice HDB has moved to launching SBF together with its BTO exercises (which now run around three times a year) in a single application window, rather than as separate standalone rounds — so you can weigh a new project against the balance flats side by side.
Who it’s for
SBF and Open Booking suit buyers who need a home sooner than a BTO allows, missed out on the ballot, or value a shorter, more certain timeline over maximum choice. As always, a quicker flat is only a good buy if it’s a good home — screen the specific unit for lease and daily-life fit using the screening checklist and the liveability rankings before you commit.
Figures on this page are computed from the current snapshot and update each rebuild. Contains information from data.gov.sg (Singapore Open Data Licence) and OneMap, Singapore Land Authority. This is general information for research, not financial or professional advice.
Frequently asked questions
- How is Sale of Balance Flats different from a BTO?
- A BTO is a brand-new project you ballot for, with construction starting after enough units are booked — hence a wait of roughly four to five years. SBF offers leftover flats from earlier exercises, a mix of under-construction and already-completed units, so the wait is much shorter and you can sometimes collect keys almost immediately. Both allocate flats by ballot; eligibility is the same.
- What is Open Booking of Flats?
- Open Booking releases the flats still unsold after an SBF exercise, on a first-come-first-served basis with no ballot. Applicants get a queue number and can book a flat as early as the next working day where units are available. It's the fastest way to a new HDB flat, but the remaining choice is limited because the more desirable units are usually already taken.
- Is the eligibility for SBF the same as for a BTO?
- Yes. Sale of Balance Flats and Open Booking use essentially the same eligibility rules as a BTO — citizenship, minimum age, income ceilings and first-timer priority. HDB now typically launches SBF alongside its BTO exercises in the same application window, so you can consider a new project and the balance flats together.