A market order prioritizes getting the trade executed. A limit order prioritizes the price you are willing to accept.
That one distinction explains most of the practical difference, but neither order type guarantees a perfect outcome.
Market order
A market order instructs a broker to buy or sell promptly at the best available prices. It generally provides greater execution certainty, but it does not guarantee the price shown on your screen.
Investor.gov states that a market order guarantees execution but not the execution price, and that the last-traded price is not necessarily the price at which the order will fill: Types of Orders.
Example
A stock displays a bid of $49.95 and an ask of $50.05. You send a market order to buy 100 shares. If enough shares are available, the order might fill around $50.05. If the market moves or available liquidity is thin, some or all of the order may fill higher.
The difference between the expected price and actual execution price is commonly called slippage.
Limit order
A limit order sets the worst price you will accept.
- A buy limit order can execute only at the limit price or lower.
- A sell limit order can execute only at the limit price or higher.
If you enter a buy limit at $50, you should not pay more than $50 if the order executes. The trade may fill partially or not fill at all.
Example
The same stock trades near $50.05. You submit a buy limit for 100 shares at $49.80. If sellers never offer shares at $49.80 or below while the order is active, you buy nothing.
Side-by-side comparison
| Question | Market order | Limit order |
|---|---|---|
| Main priority | Execution | Price control |
| Execution guaranteed? | Generally intended for prompt execution, but market disruptions can still matter | No |
| Price guaranteed? | No | Limit price or better if executed |
| Partial fill possible? | Yes | Yes |
| Main risk | Unexpected execution price | Missing the trade |
| Often considered when | A liquid security is trading normally and prompt execution matters | Price matters more than speed or volatility/liquidity is a concern |
FINRA explains the same trade-off and warns that quoted and execution prices can differ in fast-moving markets: Order Types.
Why bid, ask, spread and liquidity matter
The bid is the highest displayed price a buyer is currently offering. The ask is the lowest displayed price a seller is currently requesting. The difference is the spread.
A heavily traded large-company stock may have a one-cent spread and substantial depth. A thinly traded small-cap stock may have a much wider spread with few shares available at each price. A market order is more exposed to an unexpected fill in the second situation.
Order size matters too. A 10-share order can interact with the available market differently from a 10,000-share order.
What happens outside regular trading hours?
Extended-hours markets commonly have lower liquidity, wider spreads, and higher volatility. Available order types and broker rules can differ. FINRA recommends checking the broker’s procedures and explains that extended trading can carry lower-liquidity and higher-volatility risks: Trading Terms and Time Parameters.
Common mistakes
Treating the last price as an offer
The last price reports a completed transaction. It does not promise that shares are currently available to you at that price.
Assuming a limit order must fill after the chart touches the price
Other orders may be ahead of yours, displayed data may be aggregated, and insufficient shares may be available. A touched limit is not always a completed trade.
Forgetting the time-in-force setting
A day order normally expires at the end of the trading session. A good-til-canceled order can remain active under the broker’s time limits. Verify the selected duration before submitting.
Using a market order in an extremely volatile or illiquid security without understanding the spread
Speed can be expensive when available prices change quickly.
Which order type is better?
Neither is universally better. The choice depends on whether speed or price control matters more, along with liquidity, volatility, order size, trading hours, and the consequences of not being filled.
Before trading, review the live bid and ask, the order preview, the time-in-force setting, and your broker’s execution policies.
Educational use only: This page explains order mechanics and is not a recommendation to trade any security. Broker features and market rules can differ.