32-bit

The range of integer values that can be stored in 32-bits is 0 through 4,294,967,295 or −2,147,483,648 through 2,147,483,647 using two's complement encoding. Hence, a processor with 32-bit memory addresses can directly access 4 GB of byte-addressable memory.

The external address and data buses are often wider than 32-bits but both of these are stored and manipulated internally in the processor as 32-bit quantities. For example, the Pentium Pro processor is a 32-bit machine, but the external address bus is 36 bits wide, and the external data bus is 64 bits wide.

Architecture
Prominent 32-bit instruction set architectures include the IBM System/360, the DEC VAX, the ARM, the MIPS, and the Intel IA-32.

Images
In digital images/pictures, 32-bit can refer to 24-bit truecolor images with an 8-bit alpha channel.

Alternatively it may refer to 32-bit per channel rather than 24-bit colour + 8-bit alpha. 32-bit per channel images are used to represent values brighter than white, these values can then be used to more accurately retain bright highlights when either lowering the exposure of the image or when it is seen through a dark filter or dull reflection.

An example of this would be the reflection seen in an oil slick; even though the reflection is only a fraction of that seen in a mirror surface, the reflection of highlights can still be seen as bright white areas, not dull grey shapes.

32-bit file format
A 32-bit file format is a binary file format for which each elementary information is defined on 32-bits (or 4 Bytes). An example of such a format is the Enhanced Metafile Format.