Practice · lesson 22 of 22
Limit orders on Kalshi and Polymarket: how to use them and why they cost less
A limit order sets the price you are willing to pay or accept and waits on the order book until someone trades with it. It can save you the spread and, on Polymarket, the taker fee, at the risk of never filling. The order types each exchange offers, how fees treat them, and what happens to unfilled orders.
In one minute
- A market order fills now at the best available price; a limit order fills only at your price or better.
- Polymarket never charges makers, the side whose order rests on the book; Kalshi charges makers on some markets.
- Limit orders can fill in parts, and you can cancel the unfilled rest.
- Resting orders are cancelled when a market closes; on Polymarket, sports orders are cancelled when the game starts.
Market order or limit order
A market order takes whatever is on the book right now. On Polymarket it is a limit order priced to fill at once, and any part that cannot fill is cancelled rather than left waiting (Polymarket, order lifecycle). Kalshi calls it a Quick Order. A limit order sets the most you will pay, or the least you will accept when selling; if nothing matches, it rests on the order book until someone trades with it (Kalshi, limit orders).
The difference is the spread. If YES has a 40¢ bid and a 44¢ ask, a market buy pays 44¢; a limit buy at 41¢ pays 3¢ less per contract, if someone sells to you. In a fast market, it may never fill. How bids and asks work: bid vs ask.
Order types on each exchange
Type | What it does | Polymarket | Polymarket US | Kalshi |
|---|---|---|---|---|
Good till cancelled (GTC) | Rests until filled or cancelled | Yes | Yes | Yes |
Good till date (GTD) | Rests until a time you set | Yes | Yes | Yes, by expiry time (API) |
Fill or kill (FOK) | Fills completely now, or not at all | Yes | Yes | Yes |
Fill and kill / immediate or cancel | Fills what it can now, cancels the rest | Yes (FAK) | Yes (IOC) | Yes (IOC) |
Post-only | Rejected if it would trade at once | Yes, with GTC or GTD | Not documented | Yes (API) |
Sources: Polymarket, placing orders, Polymarket US, order types and Kalshi, create order. On Polymarket a GTD order must be set at least three minutes ahead, and expires a minute before the time you give. The Polymarket US app offers expiry choices such as good till cancelled or the start of a game.
How fees treat limit orders
- Polymarket: “Makers are never charged fees. Only takers pay fees.” A limit order that rests and is later filled pays nothing, and makers can earn rebates; see Polymarket fees.
- Polymarket US: takers pay a fee; resting orders that fill can earn a maker rebate, credited when they fill.
- Kalshi: maker fees apply on some markets, charged only when a resting order is filled, and cancelling is free (Kalshi fees). Check the market’s fee before relying on a resting order being cheaper; the general schedule is in Kalshi fees.
Partial fills, ticks and closing
- Partial fills: a limit order can fill in pieces as different traders take parts of it. What has filled stays filled; only the rest can be cancelled (Polymarket help centre).
- Price steps: each market has a tick size, from 1¢ down to fractions of a cent, and an order at a price off the tick is rejected. Kalshi now prices some markets in tenths of a cent.
- Minimum size: Polymarket sets a minimum number of shares per market; Kalshi allows fractional contracts on markets that support them.
- At the close: Kalshi cancels resting orders shortly after a market closes, and then rejects all order changes (Kalshi, market lifecycle). On Polymarket, open limit orders on sports markets are cancelled automatically when the game begins.
Research on Kalshi found that traders whose orders rested on the book lost far less on average than those who took prices; see how to make money on Kalshi.
See it live on Kalshi
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Common questions
What is a limit order on Kalshi?+
An order that sets the most you will pay per contract, or the least you will accept when selling. If nothing matches it, it rests on Kalshi’s order book until another member trades with it or you cancel it.
Are limit orders cheaper on Polymarket?+
Usually. Polymarket never charges makers, so a limit order that rests and is later filled pays no fee and avoids the spread. A limit order that matches immediately is a taker and pays the normal fee.
Do limit orders expire on Polymarket?+
Good-till-cancelled orders stay until filled or cancelled; good-till-date orders expire at the time you set. Open orders on sports markets are cancelled automatically when the game begins.
Can a limit order partly fill?+
Yes, on both exchanges. Different traders can take parts of it; the filled part stays filled and you can cancel the remainder.