Buying guide

How to Choose GT2 Timing Belt Length and Width

GT2 belt length, tooth count and width explained, with examples for 3D printers and CNC machines.

Length = number of teeth × 2 mm

GT2 (2GT) belts have a 2 mm pitch, so the belt length in millimeters is the tooth count multiplied by 2. A closed-loop GT2 belt of 200 mm has 100 teeth, and a 400 mm belt has 200 teeth. Closed-loop lengths are always a multiple of 2 mm.

How to find the length you need

1. Measure the old belt. Cut it open, lay it flat and count the teeth, or measure the length and divide by 2.
2. For a new design, add the distance around both pulleys and idlers along the belt path: twice the center distance, plus half the circumference of each pulley.
3. If you are between two sizes, choose the nearest length and adjust with a tensioner or slotted mount.

Closed-loop or open-end belt?

Closed-loop belts are seamless and sized for a fixed path, which suits CoreXY printers and axis drives. Open-end belt is sold by the meter or in a full roll and is cut to length for gantries, linear actuators and long runs. Browse GT2 belts.

Which width?

6 mm is the standard width on most 3D printers. 9 mm and 10 mm carry more load and are used on larger machines and light CNC axes. The pulley width must match the belt width, so check the pulley before ordering.