Binance Spot Post Only, IOC and FOK orders answer different execution questions. Post Only prevents a limit order from immediately taking liquidity; if it would match at entry, it is canceled. IOC attempts an immediate fill and cancels any remainder, while FOK requires the entire order to fill immediately or cancels it. These are order instructions, not guaranteed ways to get a better price or lower fee.
Key takeaways
- Post Only is designed to add liquidity rather than execute against a resting order at placement.
- IOC can fill partially; its unfilled quantity is canceled.
- FOK fills completely at once or does not fill.
- Check the live Spot order ticket and fee preview: interface, pair, region, and account eligibility can differ.
What do Post Only, IOC and FOK mean?
A Spot limit order specifies a price and quantity. The order instruction controls what happens when the order reaches the book. Post Only concerns whether the order may immediately cross the spread. IOC (Immediate or Cancel) and FOK (Fill or Kill) are time-in-force choices. GTC (Good Till Canceled) is a useful baseline: any unfilled amount can remain open until filled or canceled, subject to the exchange’s rules.
| Instruction | At submission | Partial fill? | Unfilled quantity |
|---|---|---|---|
| Post Only | Must rest on the book rather than execute immediately | May fill later as liquidity is taken | Order is rejected or canceled if it would immediately match; otherwise it can remain open |
| GTC | May execute immediately or rest, depending on price and market | Yes | Usually stays open until filled or canceled |
| IOC | Attempts execution immediately | Yes | Canceled immediately |
| FOK | Requires immediate execution of the entire quantity | No | Entire order canceled if full execution is unavailable |
Illustration: Suppose a buy order asks for 12 units at a limit price, but only 10 units are available at that price or better when it arrives. An IOC order could fill 10 and cancel 2; an FOK order would cancel unless all 12 can fill immediately. A GTC order could leave 2 open after an initial fill. Actual matching depends on the changing order book and trading rules; this is not a prediction of a live fill.
Does Post Only guarantee a maker fee? Are IOC and FOK taker orders?
Binance’s maker/taker explanation says Post Only is intended to keep an order from taking liquidity when placed, and describes IOC and FOK orders submitted through its API as taker orders. A normal GTC limit order can include both maker and taker fills. Do not infer a specific fee percentage from an order label: your Spot pair, VIP tier, applicable discounts, account and region determine the charge. Check the actual fill and fee record, as explained in our Binance maker vs taker fee guide and actual Binance trading-fee checklist.
How to check and place the order in your Binance account
- Open Binance Spot for the intended pair and confirm that Spot trading is available to your account and region.
- Choose the limit-order area and inspect the current advanced order or time-in-force choices. Binance’s help article describes an Advanced order mode on the website; availability may vary by interface and version, so use the options actually shown in your account.
- Enter the limit price and quantity. Check minimum quantity, notional and price-filter rules before submitting.
- Before confirmation, verify whether you selected Post Only, GTC, IOC or FOK, and inspect the displayed fee and order summary. Do not assume that all instructions can be combined.
- After submission, inspect Open Orders and Order History for the final status. Review Trade History or the fee details for any executed portion. A canceled IOC may still have a partial fill.
Exceptions and limits
These instructions cannot create liquidity or guarantee a fill. Fast-moving prices, available depth and exchange filters affect execution. A Post Only order that would match immediately may be canceled rather than repriced; verify the exact status in your order history. Binance’s help article also notes that Iceberg orders are not supported with IOC or FOK. The placement controls and eligible products can change by market, account or region. This article concerns Spot orders, not Futures, Margin or P2P.
For triggered exit orders, see our separate Spot stop-limit and OCO guide. A trigger is a different concept from IOC/FOK time in force; neither guarantees execution.
Frequently asked questions
Why did my Post Only order cancel immediately?
The limit price likely would have matched an existing order at entry, so it could not be posted as maker liquidity. Check the order status and current book before trying again; do not repeatedly submit without understanding the price.
Can an IOC order show canceled but still have a trade?
Yes. Its immediately executable portion can fill while the rest is canceled. Check both Trade History and Order History, not just the final canceled label.
Does FOK guarantee the limit price?
It caps the acceptable price specified in the limit order, but does not guarantee a fill. If the full quantity cannot execute immediately within the order conditions, the order is canceled.
Which option is cheapest?
No order instruction guarantees the lowest total cost. Compare the actual execution price, spread and applicable account fee; the market can move while an order waits or after it cancels.
Official Binance sources and review date
- Maker (Post Only), Time in Force and Iceberg order FAQ (Binance Support, en-NZ).
- Market Makers and Takers (Binance Support, en).
- How to Place a Time in Force Order (Binance Academy, en).
- Binance Spot Trading Rules (Binance Academy, en).
Last reviewed: September 23, 2026. Bimence explains the cited Binance documentation; interface availability and fees must be checked in your own account.
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Risk disclosure: Orders may not fill, may fill only partly, or may execute at a cost different from your expectation. Digital-asset trading can involve substantial loss. Availability varies by jurisdiction. Read our Risk Disclosure.