Lot vs Contract size
Look-alike pair
Full entries: Lot · Contract size.
A lot and contract size are not the same thing: a lot is a unit of quantity used to place orders, while contract size is the number of underlying units that one lot represents. The single difference that matters is that lot is the order unit, and contract size is the conversion factor that tells you how much market exposure that order unit carries.
Side by side
| Lot | Contract size | |
|---|---|---|
| Definition | A standardized order quantity, often expressed as a number of lots (e.g., 1 lot, 0.1 lot). | The number of underlying units (shares, barrels, ounces, etc.) that one lot represents. |
| Role in trading | Used to specify how much to buy or sell in an order ticket. | Used to calculate the notional value and profit/loss per price movement. |
| Typical values | Common lot sizes include standard, mini, micro, and nano, but the exact meaning varies by broker and instrument. | Contract size is fixed by the instrument or exchange and can be 1, 100, 1000, 100000, or another number, varying by product. |
| Field mark | On a trading platform, the order entry field labeled 'Volume' or 'Lots' shows the number of lots. | In the instrument specifications, a field labeled 'Contract size' or 'Units per lot' shows the number of underlying units per lot. |
| Example | Buying 2 lots of an instrument. | If contract size is 100,000, then 2 lots equal 200,000 units of the underlying. |
| Variation | Lot definitions and available sizes vary by broker, country, and regulator. | Contract size varies by instrument, exchange, and broker. |
Which word to use
Lot is the right word when you are stating the quantity you want to trade, while contract size is the right word when you are converting that quantity into actual market exposure or calculating the value of a price move.
Family: XI · Look-alikes · Index A–Z