ATX Motherboard Dimensions

The full ATX motherboard size is 12 in long by x 9.6 in wide (305 mm x 244 mm). Since it came out in 1995, the ATX computer form factor has replaced the old AT form in virtually all computers. ATX means Advanced Technology Extended.

Variants of the ATX Design

There are numerous variants of the basic ATX. They include the FlexATX motherboard design. It measures 9 in (229 mm) x 7.5 in (191 mm). The microATX motherboard measures 9.6 in (244 mm) x 9.6 in (244 mm). The EmbATX has the same physical specifications as the microATX. The Mini ATX is 11.2 in (284 mm) long and 8.2 in (208 mm) wide.

The ATX motherboard size of 12 in (305 mm) by 9.6 in (244 mm) is regarded as the standard. The EATX (or extended ATX) measures 12 in (305 mm) x 13 in (330 mm) and the EEATX (enhanced extended ATX) is 13.68 in long (347 mm) by 13 in (330 mm).

The WTX (workstation ATX) motherboard is 14 in (356 mm) by 16.75 in (425 mm). A new version called the XL-ATX was released in 2008. The physical measurements are the same as the standard ATX but it comes with ten slots.

Another version of the XL ATX called the EVGA X58 Classified 4-Way SLI, measures 13.5 in by 10.3-in wide. The computer form factor comes with 7 slots.

The ATX & Other Computer Form Factors

The following compares the ATX motherboard size with those of other computer form factors. The measurement is length by width and in millimeters.

The WTX measures 356 by 425 mm. The AT measured 350 × 305 mm, the Baby-AT 330 × 216 mm and the BTX 325 × 266 mm. While the typical ATX is 305 × 244, the EATX is 305 × 330 mm and the LPX is 330 × 229 mm.

The microBTX measures 264 x 267 and the NLX form factor 254 × 228 mm. The microATX measures 244 × 244; the DTX computer form factor is 244 × 203 and the FlexATX is 229 × 191 mm. The Mini-DTX measures 203 × 170 mm. The EBX computer form factor measures 203 × 146 mm and the microATX (Min.) measures 171 × 171 mm.

Compared to the standard ATX motherboard size, the Mini-ITX

computer form factor measures 170 × 170 mm. The EPIC (Express), on the hand is 165 × 115 mm. The ESM measures 149 × 71; the Nano-ITX measures 120 × 120 and the COM Express 125 × 95 mm. The ESMexpress computer form factor dimensions are 125 × 95 mm and the ETX / XTX, 114 × 95.

The Pico-ITX computer form factor is 100 × 72 mm, while the PC/104 (-Plus) is 96 × 90 mm. The mobile-ITX measures 75 × 45 mm and the Ultra ATX × 244 mm.

With its popularity, the ATX motherboard size has become very popular among people who like to assemble their own computers. That is the reason why numerous variants have appeared and continue to appear.