At a fundamental level a pointer is just a number which represents a memory address. The size of a pointer depends on the platform, for 64 bit platforms the size is 64 bits (8 bytes) and for 32 bit platforms the size is 32 bits (4 bytes), but the size is always the same for a given platform regardless of the pointer’s type. printf("%d\n", sizeof(int*)); printf("%d\n", sizeof(char*)); printf("%d\n", sizeof(void*)); printf("%d\n", sizeof(MyCustomType*)); A memory address specifies the location of a single byte in memory, if we wanted to read only a single bit from memory, we would have to read a whole byte and then do some bit twiddling to extract the bit we were interested in.