C – Types – uint8_t, uint16_t, uint32_t and uint64_t

Type Bits Bytes
uint8_t 8 bits 1 byte
uint16_t 16 bits 2 bytes
uint32_t 32 bits 4 bytes
uint64_t 64 bits 8 bytes

The fixed types uint8_t, uint16_t, uint32_t and uint64_t are equal respectively to (in most cases depending on the platform & compiler): unsigned char, unsigned short, unsigned int and unsigned long long.

The fixed types were introduced to be just that, fixed types independent of the platform.

h/t: http://www.badprog.com/c-type-what-are-uint8-t-uint16-t-uint32-t-and-uint64-t