Following is a list of motherboard types and form factors that have been used in PCs since the first IBM PC in 1981. The "TX" stands for "Technology Extended."
Year Width-Length
Intr. Type (Inches)
BTX (Balanced TX)
2004 BTX 12.8x10.5
2004 microBTX 10.4x10.5
2004 picoBTX 8x10.5
ATX (Advanced TX)
1999 FlexATX 9x7.5
1997 microATX 9.6x9.6
1996 Mini ATX 11.2x8.2
1995 ATX 12x9.6
1995 EATX 12x13
ITX - (Information TX)
2009 Mobile ITX 2.4x2.4
2007 Pico ITX 3.9x2.8
2005 Nano ITX 4.7x4.7
2002 Mini ITX 6.7x6.7
WTX (Workstation TX)
1998 WTX 14x16.75
LOW PROFILE
(Cards plug into riser)
2002 EmbATX 9.6x9.6
1997 NLX 9x13.6
1987 LPX 9x13
1987 Mini LPX 9x11
FIRST PCs
1987 Micro AT 8.5x8.5
1987 Baby AT 8.5x13
1984 AT 12x13
1981 PC/XT 8.5x13