Router Bit Speed Calculator — Safe RPM

The tip of a large bit travels much faster than a small bit at the same RPM. If the peripheral speed is too high, the wood burns, the bit overheats, and the cut quality suffers. A 50mm bit at 24000 RPM has a tip speed of nearly 63 m/s — dangerously fast.

Too high a speed causes burning, premature bit wear, and poor cut quality. It can also be dangerous with large bits. Always start at the lower end of the recommended range and increase if needed.

A 12mm (about 1/2 inch) router bit is small enough to run at the router's full speed — typically the maximum 24,000 RPM. The spindle speed chart is the same for softwood, hardwood and MDF; the wood species mainly affects your feed rate, not the RPM. Step the speed down only as bit diameter grows, and increase feed rate to prevent burning.