Speeds and Feeds Calculator
Calculate spindle RPM and feed rate for milling and drilling operations from cutting speed, tool diameter, flute count, and chip load.
Results
What is it?
Speeds and feeds are the two fundamental parameters of any machining operation. Cutting speed (SFM or m/min) describes how fast the tool's cutting edge moves through the material. Spindle RPM converts cutting speed to rotational speed for a given tool diameter. Feed rate then converts RPM รโ chip load รโ flutes into the table travel speed.
How to use
Select your unit system, then enter the recommended cutting speed for your material/tool combination (from the tooling manufacturer's chart or a reference table), the tool diameter, number of flutes, and chip load. The calculator returns the spindle RPM and feed rate.
Example scenario
Milling 6061 aluminium with a 1/2" (0.5") 4-flute carbide end mill. Recommended cutting speed = 600 SFM, chip load = 0.003". RPM = (600 รโ 12) / (รโฌ รโ 0.5) รขโฐห 4,584 RPM. Feed Rate = 4,584 รโ 4 รโ 0.003 รขโฐห 55.0 IPM.
Pro tip
Chip load is the most critical parameter for tool life. Too light a chip load causes rubbing and heat build-up; too heavy causes chipping. Reduce speeds/feeds by 20รขโฌโ30% when machining stainless steel or titanium. Runout from worn collets dramatically reduces effective chip load รขโฌโ inspect toolholding regularly.