Router Bit Speed Chart

Router bit speed limits are set by tip speed, not by RPM. A 3-1/4 inch cutter at 12,000 RPM is already moving its cutting edge at about 116 mph — six times faster than a 1/4-inch bit at the router's full 24,000 RPM. That is why the big bits carry a speed limit and the little ones do not.

The table below is not our opinion about speeds. Every RPM figure in it is Whiteside Machine Company's own published recommendation from the individual product page for a real bit, fetched on 6 September 2026. The tip-speed column is arithmetic we did from those figures, and it is labelled as such.

The chart

How the tip speed column was calculated.Tip speed = π × diameter × RPM. For the 3-1/4 inch bit: π × (3.25 ÷ 12) ft × 12,000 RPM = about 10,210 ft/min, which is about 116 mph. You can check every row.

What the chart is actually telling you

Read down the tip-speed column and the shape of the problem appears. The small bits are not limited by the bit at all — they are limited by the router, because 24,000 RPM is simply as fast as the machine goes. From about 7/8 inch upward the limit becomes the bit's, and it tightens steadily: by 3-1/4 inches the published maximum has fallen to half the router's top speed and the cutting edge is still traveling six times faster than the small bit ever did.

Excessive tip speed does three things, in increasing order of seriousness: it burns the cut because the edge is generating heat faster than the chip carries it away; it dulls the carbide prematurely; and at the extreme it stresses a large cutter in a way no woodworker wants to discover experimentally. This is the reason variable speed is not a luxury feature on a router that will ever hold a big bit.

If the bit has no published figure

Many bits, particularly in inexpensive boxed sets, arrive with no speed marking and no documentation. The chart above is a reasonable reference for those — find the row closest to your bit's cutting diameter and treat that manufacturer's published maximum as an upper bound rather than a target.

Two further points that are worth more than any chart:

• Slow down before you speed up. Burning, chatter and a rough surface are the symptoms of running too fast for the diameter. Almost nobody has the opposite problem.
• Feed rate is the other half. Running slower and feeding too slowly still burns, because the edge dwells in one place. If the cut is burning at a sensible speed, feed faster before you drop the RPM again.

Speed by material, briefly

Whiteside publishes its recommendations per bit rather than per timber, and the recommended ranges above already sit below the maxima. Within a bit's published range, the useful rule of thumb is that dense hardwoods and anything prone to burning — maple and cherry are the classic offenders — want the lower end, while softwoods and plywood tolerate the upper end. Neither instruction overrides the published maximum for the diameter.

What this means when you are buying

A single-speed router cannot run any bit in the bottom three rows of that chart, which rules it out of cabinet-door work entirely. That makes variable speed a buying criterion rather than a feature, and it is one of the three specs we say actually decides a router purchase in which router should you buy.

The large bits in the bottom rows are also 1/2-inch shank items, and for the same underlying reason: big cutters put big loads into the shank. That trade-off is worked through in 1/4 vs 1/2-inch shanks, and the profiles themselves are catalogued in router bit types explained.

What we could not verify

We have not measured RPM, tip speed, temperature or surface finish on any bit. Every RPM figure in the chart is Whiteside's published recommendation for the named product, each one sourced below. The tip-speed column is our arithmetic from those figures and the formula is shown. The guidance about material, feed rate and unmarked bits is reasoning from how the cut behaves, not test data, and it should never override a figure printed on a bit you own.