Form Factor Table
| Form factor | Width (inches) | Length (inches) | Design type |
|---|---|---|---|
| IBM PC | 8.5 | 13 | Motherboard |
| IBM PC XT | 8.5 | 13 | Motherboard |
| AT0 | 12 | 11-13 | Motherboard |
| Baby AT | 8.5 | 10-13 | Motherboard |
| LPX | 9 | 11-13 | Backplane |
| Micro-AT | 8.5 | 8.5 | Motherboard |
| ATX | 12 | 9.6 | Motherboard |
| Mini-ATX | 11.2 | 8.2 | Motherboard |
| Mini-LPX | 8-9 | 10-11 | Backplane |
| Micro-ATX | 9.6 | 9.6 | Motherboard |
| NLX | 8-9 | 10-13.6 | Backplane |
| Flex-ATX | 9 | 7.5 | Motherboard |
| Mini-ITX | 6.7 | 6.7 | Motherboard |
| Nano-ITX | 4.7 | 4.7 | Motherboard |
A backplane is a circuit board into which other circuit boards can be plugged.
The form factor usually defines a motherboard's size, shape and how it is mounted to the case, but now includes:
- size, shape and function of the system case
- type, placement and size of the power supply
- system power requirements
- location and type of external connectors
- case airflow and cooling systems.
