HDB Option to Purchase (OTP): Where to Get It, the Fees, the 21 Days and Backing Out
How the HDB resale OTP works from download to exercise: what must be in place first, the option and exercise fees, the 21-day clock, what you pay at each step on a median flat, and what backing out costs.
The HDB option to purchase (OTP) is HDB's prescribed contract form: the seller signs it and grants it to you for an option fee of $1 to $1,000, and you have 21 calendar days, to 4pm on the 21st day, to exercise it by signing the acceptance and paying an exercise fee, with both fees capped at $5,000 together. The seller needs an Intent to Sell registered for 7 days, and you need a valid HFE letter. Exercising it makes a binding contract; letting it lapse costs you only the option fee. Buyer's stamp duty, $13,500 on a median $630,000 4-room flat, is due within 14 days of the contract, and HDB collects it for IRAS from your CPF.
In an HDB resale, the option to purchase (OTP) is the moment the deal becomes real. The seller signs HDB's prescribed form and hands it to you for an option fee; you then have 21 days to check the value, line up the loan and decide. Exercise it and you have a binding contract; let it lapse and you lose the fee.
This guide walks through where the form comes from, what must be in place first, the fees and deadlines, and what you pay at each step on a median-priced $630,000 4-room flat. Rules are HDB's, CPF's and IRAS's, as at 19 September 2026.
What is an HDB option to purchase (OTP)?
It is HDB's prescribed contract form for a resale flat. The seller fills it in, signs it and grants it to you for an option fee, promising to sell at the agreed price for 21 days. If you exercise it within that time, you and the seller have a binding contract; no other agreement about the sale is valid.
Two things make the HDB OTP different from a private-property option:
- It is the only valid contract. "You and the flat sellers must use the HDB-prescribed OTP for the resale transaction. Any other agreements and/ or supplementary agreements relating to the sale or purchase of the flat are not valid under the Housing and Development Act" (HDB).
- It is fixed. The current form has been in use since 1 January 2018, and "No amendments may be made to the prescribed form" (HDB Important Notes).
"The OTP is a legally binding contract between you and the flat sellers." Until you exercise it, it binds the seller: "Once the flat sellers have granted the OTP to you, they cannot grant another OTP to other flat buyers until the OTP granted to you has expired" (HDB).
The OTP buys you 21 days of exclusivity; exercising it turns them into a contract.
Where do you get the HDB OTP form, and can you download it?
The seller downloads it. After registering an Intent to Sell on My Flat Dashboard, the seller is prompted to download a copy of HDB's prescribed OTP through HDB's e-service. Only one copy should be printed: each form carries a unique serial number, which goes on the resale application.
HDB to sellers: "After you have registered your Intent to Sell, you will be prompted to download a copy of the HDB-prescribed OTP" (HDB; the form comes from HDB's OTP download service). And to both sides: "Print only 1 copy of the OTP as each form has a unique serial number. You must state the serial number of the OTP when you submit a resale application to HDB" (HDB).
Every resale application goes through the HDB Flat Portal: "All resale applications are processed via the HDB Flat Portal" (HDB Important Notes), and no amendments may be made to the form.
If you are buying, the OTP comes to you from the seller: you never download it yourself.
What must be in place before the seller can grant you an OTP?
The seller must have registered an Intent to Sell at least 7 days earlier and met the minimum occupation period; an OTP granted before MOP is void. You must hold a valid HDB Flat Eligibility (HFE) letter. If you are borrowing from a bank, you also need its Letter of Offer before you exercise the OTP.
| Who | What HDB requires | When |
|---|---|---|
| Seller | A valid Intent to Sell, registered "at least 7 days before granting an Option to Purchase" | Before granting |
| Seller | The minimum occupation period met, "otherwise the OTP entered into will be null and void" | Before granting |
| Buyer | A valid HFE letter; for an HDB loan, one showing your loan eligibility | Before the OTP is granted |
| Buyer with a bank loan | A Letter of Offer issued before you exercise the OTP | Before exercising |
Sources: HDB Important Notes; HDB.
Both documents must still be valid when the resale application goes in, and the people in your application must match those in your HFE letter. See the HFE letter explained.
No HFE letter, no OTP: get the letter before you start viewing seriously.
How much are the HDB option fee and option exercise fee?
The option fee is $1 to $1,000, paid when the seller grants the OTP. The option exercise fee is paid when you exercise it, and the two together cannot exceed $5,000. Neither can be $0. Both are negotiable, both count towards the price, and CPF says the option fees cannot be paid from CPF.
| Payment | When | Amount |
|---|---|---|
| Option fee | When the seller grants the OTP | "Between $1 and $1,000" |
| Option exercise fee | When you exercise the OTP | "An amount, which when including the Option Fee, will not exceed $5,000" |
Source: HDB.
The rules around them:
- Neither fee can be $0, "to ensure that there is a valid Option or contract" (HDB Important Notes).
- They are part of the price, not extra: "You may negotiate the amounts … which will form part of the resale price."
- They are cash. CPF: "Do note that the option fees cannot be paid using your CPF" (CPF).
- Pay the seller, with proof. HDB encourages "digital payment modes to secure independent proof of payment". If the seller authorises a property agent or a lawyer to receive the signed OTP, pay by cheque made out to the sellers: HDB notes that agents and lawyers "are not allowed to receive cash" for the people they act for.
The option fee is the price of walking away; the exercise fee is the price of staying.
How long do you have to exercise the OTP, and what must happen first?
21 calendar days, weekends and public holidays included, expiring at 4pm on the 21st day: an OTP granted on 1 April expires on 22 April at 4pm. If you use CPF or a loan, submit a Request for Value by the next working day and wait for the result, usually within 10 working days, before you exercise. The 21 days are prescribed by HDB, and the form cannot be amended.
The clock is HDB's: "Option expiry date (21 calendar days from the option day, including Saturdays, Sundays and Public Holidays. For e.g., if the flat sellers grant an Option to you on 1 April, the Option will expire on 22 April at 4pm)" (HDB).
What has to fit inside it:
- Request for Value, by the next working day after the option date, with page 1 of the OTP and a $120 processing fee. The value sets "the basis for your CPF usage and/ or the reference for the housing loan amount" (HDB).
- Wait for the value. The outcome is "typically available within 10 working days", and "You have to wait for the outcome of the Request for Value before you may exercise the OTP".
- Confirm your financing on My Flat Dashboard, and for a bank loan get the Letter of Offer.
- Decide. HDB: "You should use the Option Period wisely and not rush into exercising the OTP" (HDB), but do "not wait till the last hour", because the OTP simply expires (HDB Important Notes). The option fee, deposit and option period are "prescribed", and the form cannot be amended.
Paying cash only, with no CPF and no loan? You don't need a Request for Value.
Ten working days for the value leaves you about a week to decide: plan for it before you sign.
How do you exercise an HDB OTP?
Within the option period, every buyer signs the "ACCEPTANCE" section on page 8 of the OTP, you return the signed OTP to the seller and pay the option exercise fee. That creates a binding contract. Then both sides submit their portions of the resale application within the days agreed on page 4, and within 7 days of each other.
HDB's steps (HDB):
- Sign the acceptance. "You and all your co-buyers must sign on the “ACCEPTANCE” section" (page 8). A witness aged 21 or over, not involved in the sale, may sign too.
- Return it and pay. Return the signed OTP to the seller, or to the person the seller named in the OTP's authorisation form, and pay the option exercise fee.
- Keep proof. HDB advises buyers "to obtain a signed acknowledgement from the sellers on the buyer's copy of the Acceptance, stating the date and time of exercise" (HDB Important Notes).
- Submit the resale application. Both portions go in "Within the agreed number of days as stated on page 4 of the OTP, and Within 7 days of each other’s submission".
"Upon exercise of the OTP, the sellers and the buyers enter into a binding contract for the sale and purchase of the flat." From that contract, IRAS's clock runs: "you need to pay Stamp Duty within 14 days of the date of Contract/Agreement. HDB has been authorised by IRAS to collect stamp duty on its behalf" (IRAS).
Signing the acceptance is the point of no return, so do it only once the value and the loan are known.
Can the buyer or the seller back out after the OTP is signed?
Before you exercise it, you can: let the OTP lapse and you lose only the option fee. The seller cannot: once the OTP is granted, the seller cannot sell the flat or make an offer to anyone else until it expires. After you exercise it, you both have a binding contract, and HDB leaves any claim between you to that contract.
| Stage | Buyer | Seller |
|---|---|---|
| OTP granted, not exercised | Can let it expire: "Upon expiry of the OTP, you will forfeit the Option Fee" | Bound: "cannot sell the flat or make an offer to other buyers" during the 21 days |
| OTP exercised | Bound by the contract | Bound by the contract |
Sources: HDB; HDB Important Notes.
After exercise, a resale can still be delayed or cancelled if either side misses HDB's deadlines to endorse documents, pay or meet the approval conditions. HDB says this "shall not in any way prejudice the rights of the sellers or buyers to take such action (if any) as they may deem fit pursuant to the contract", "including but not limited to any late completion interest", and that "HDB shall not be responsible or liable to any party" for the fallout (HDB Important Notes). If the other side pulls out after exercise, get legal advice.
Before exercise, walking away costs the option fee; after exercise, you are in a contract.
What do you pay, and when, from the OTP to completion?
On a median $630,000 4-room flat with an HDB loan and the price at HDB's value: up to $1,000 at the OTP, $120 for the Request for Value, up to $5,000 in all by the time you exercise, $13,500 of stamp duty that HDB collects from your CPF, $500 of stamp duty on the loan, $789.84 in HDB's legal and fixed fees, a $157,500 initial payment, and the $472,500 loan at completion.
| Step | When | What | Amount | Cash or CPF |
|---|---|---|---|---|
| 1. Seller grants the OTP | On the option date | Option fee, agreed with the seller | $1 to $1,000 | Cash: CPF says the option fees cannot be paid from CPF |
| 2. Request for Value | By the next working day | HDB processing fee | $120 (incl. GST) | Paid online to HDB |
| 3. You exercise the OTP | Within the 21-day option period, after the value is out | Option exercise fee: with the option fee, capped at $5,000 | Up to $5,000 minus the option fee | Cash |
| 4. Buyer's stamp duty | Due within 14 days of the contract; HDB collects it for IRAS, from CPF, with any shortfall at completion | BSD on the higher of price or value | $13,500 | CPF (cash on written request) |
| 4a. Stamp duty on the HDB loan | Collected with the other fees | 0.40% of the loan, capped at $500 | $500 | As HDB directs |
| 5. Legal fees, if HDB acts | After you endorse the resale documents | HDB's transfer fee plus the fixed search, registration, caveat and miscellaneous fees | $789.84, plus HDB-loan mortgage fees | CPF can pay legal fees |
| 6. Initial payment | After you endorse the resale documents | 25% of the lower of price or value | $157,500 | Cash and/or CPF, incl. eligible grants |
| 7. Completion | About 8 weeks after HDB accepts the application | The balance, from the HDB loan (up to 75%) | $472,500 | HDB loan |
PropKaki arithmetic at the national median 4-room price for 2026 H1 (5,379 resales), for Singapore Citizen buyers; PR households also pay ABSD at completion. The deposit is part of the price, so the rows are not a total.
Stamp duty follows the higher of price and value. IRAS charges buyer's stamp duty "based on the purchase price or market value of the property, whichever is higher" (IRAS); on the 4-room median it is $1,800 + $3,600 + 3% of the next $270,000:
| Flat type | Median resale price | Buyer's stamp duty | Resales (n) |
|---|---|---|---|
| 3 Room | $443,000 | $7,890 | 2,925 |
| 4 Room | $630,000 | $13,500 | 5,379 |
| 5 Room | $740,000 | $16,800 | 2,793 |
| Executive | $910,000 | $21,900 | 741 |
If you agree a price above HDB's value, remember that the value, not the price, is "the basis for your CPF usage" and the loan (HDB): plan the difference in cash. To see these payments against your own savings and CPF, use the property financial planner; for the dates, the property timeline planner.
The OTP stage costs a few thousand dollars in cash; the stamp duty can come from CPF.
How long does it take from the OTP to completion?
About four months if every step takes HDB's full stated time: up to 21 days to exercise, up to 28 working days for HDB to accept the application, then about 8 weeks to completion, the earliest possible date, plus the days you agree for submitting it. Completion can be deferred only if buyer and seller both ask in writing.
HDB's timetable (HDB; HDB Important Notes):
| Step | Timing |
|---|---|
| Exercise the OTP | Within 21 calendar days of the option date |
| Submit the resale application | Within the days agreed on page 4 of the OTP, and within 7 days of each other |
| HDB accepts the application | "within 28 working days" of a complete application |
| Documents to endorse | "about 3 weeks after the application has been accepted" |
| Resale approval | About 2 weeks after both sides endorse and pay (HDB) |
| Completion | "about 8 weeks from the date of HDB’s acceptance of the resale application" |
The four months are PropKaki's sum of HDB's stated maximums; it is shorter if the value comes early and HDB accepts quickly. Completion cannot be brought forward: "As this is the earliest possible date to complete the transaction, HDB will not be able to accede to any request to advance the completion date". A later date needs a joint request from buyer and seller. If you are also selling a flat or a private home, map both sales in the property timeline planner. For the seller's side, see how long it takes to sell an HDB flat.
Count from HDB's acceptance, not from the OTP: completion is at least 8 weeks after it.
Is an option to purchase the same as an offer to purchase?
No. An option to purchase is the seller's written offer to sell, held open for a fee for a fixed time; you accept it by exercising it, and that makes the contract. A buyer's letter offering a price is a different document, and for an HDB flat it counts for nothing: only HDB's prescribed OTP is valid.
CEA's standard template and IRAS both describe the option as the seller's offer. CEA's template for private homes opens with the seller's promise: "In consideration of the sum of … (the “Option Money”) … the Vendor hereby offers to sell to the Purchaser the Property" (CEA), and IRAS treats a buyer's acceptance of an OTP as accepting the seller's "offer" (IRAS). CEA's template is "not mandated", and it leaves the option period to be filled in, with "two weeks from the date of this Option" as one choice.
For an HDB flat, a separate offer letter adds nothing: "Any other agreements and/ or supplementary agreements relating to the sale or purchase of the flat are not valid under the Housing and Development Act" (HDB). For a private home, PropKaki's paperwork assistant fills in CEA's option template.
What is the biggest mistake people make with an HDB OTP?
Agreeing a price before knowing what HDB will value the flat at. Your loan and CPF follow HDB's value, not the price, so any amount above the value is cash you must find, and you cannot exercise until the value is out. The other mistake is a side deal: the Housing and Development Act voids any agreement outside the OTP, and false information is an offence.
The value matters because it "will form the basis for your CPF usage and/ or the reference for the housing loan amount" (HDB), unless your bank advises otherwise. Agree a price well above it and the gap comes out of your cash.
And declare the real price. HDB requires buyer and seller to "declare the true resale price of the flat to HDB" with no side agreement that inflates or understates it. Giving false information in a resale can mean "a fine not exceeding $5,000 or … imprisonment for a term not exceeding 6 months or … both", and HDB can bar the person from buying a flat or taking an HDB loan for 5 years (HDB Important Notes).
Price the flat against its likely value first; the OTP is not the time to find out.
Official sources
Check HDB's pages directly for the current forms and rules.
Methodology and sources
Where every figure comes from, and what we deliberately did not claim.
Official rules. The OTP rules, fees, deadlines and timetable are from HDB's option-to-purchase pages for buyers and sellers (updated 7 September 2026), HDB's Important Notes on the OTP (updated 7 September 2026), its Request for Value page (April 2026), its resale overview (July 2026) and its resale approval page (August 2026). The option-fee rule on CPF is CPF Board's (28 April 2026); stamp-duty rates and deadlines are IRAS's (February and August 2026); the private-home option template is CEA's (version 1.2). All read on 19 September 2026.
Proprietary figures. The median prices are PropKaki's HDB resale records for 2026 H1 (5,379 4-room resales). The stamp duty, legal fees, initial payment and loan are PropKaki's arithmetic under IRAS's and HDB's published rules, assuming the price equals HDB's value; PropKaki's own stamp-duty tool gives the same $13,500. How we work: PropKaki methodology.
What we have not claimed: that the 21 days can be extended, what a court would award if a party backs out, or what your own flat will be valued at. This is a practical explainer, not legal or financial advice. Check with HDB, or a lawyer, before you sign.
Got a question this raised? Ask PropKaki.
Take any point from this analysis and apply it to your own project, budget or decision.
PropKakiFor most buyers this year, staying well within budget beats trying to time the market.