# Specifying Paper Sizes

Unidrv supports three categories of paper sizes--standard paper sizes, vendor-defined paper sizes, and user-defined paper sizes.

### Standard Paper Sizes

Standard paper sizes are those that are commonly supported by most printers. The dimensions of these paper sizes are predefined. For more information, see Supporting Standard Paper Sizes.

### Vendor-Defined Paper Sizes

Vendor-defined paper sizes (also called nonstandard paper sizes) are defined by a printer vendor, within a printer's GPD file. For more information, see Supporting Vendor-Defined Paper Sizes.

### User-Defined Paper Sizes

User-defined paper sizes (also called customized paper sizes) are defined by system administrators using the system's print folder, and thus are system-specific. For more information, see Supporting User-Defined Paper Sizes.

For information about how to use the system locale to specify a default paper size, see Referencing Locales.