What is a Inch per Minute?

Inches per minute is the American standard feed-rate unit for CNC machining, 3D printing, milling machines, and precision manufacturing. Machinists program tool feed rates in IPM (inches per minute) — typical values range from 5 to 100 IPM depending on material and tool. American machine controllers (Fanuc, Haas, Mazak) default to inches per minute when set to imperial mode. 3D printer feed rates are also commonly specified in IPM in US-built machines. The unit relates to inches per second (60 ipm = 1 ips), mm per minute (1 ipm = 25.4 mm/min — the metric machinist equivalent), and feet per minute (12 ipm = 1 fpm). Manufacturing CAM (computer-aided manufacturing) software allows switching between IPM and metric mm/min depending on machine controller setup.

Visual reference for how the inch per minute relates to other speed units. Each row links to the full converter for that pair.

• CNC milling and turning feed rates
• 3D printer head movement
• Some US industrial flow specifications

• ✓1 in/min = 0.000423 m/s = 0.0254 m/min.
• ✓CNC: lower in/min for harder materials; higher for softer.
• ✓Always match tool speed and material — too fast breaks bits.

• ✗Using mm/min and in/min interchangeably in CNC — 25.4× difference.
• ✗Treating 100 in/min as fast — only moderate in CNC.
• ✗Confusing feed rate with spindle RPM.