Convert surface speed between SFM, ft/min, m/min and mm/min in one step. Enter a value and pick the unit it is in — the metric-to-imperial bridge for cutting data sheets.
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Request a Proposal →Published starting values are not measurements. They are recommendations, and they differ because each manufacturer optimises for something different — tool life, surface finish, chip control, or spindle power. Two suppliers can quote the same ISO grade and give you cutting speeds 30% apart, and each figure can be right for that supplier’s own geometry, edge preparation and coating.
That is why the number this calculator returns is a starting point, not a setting. Treat the catalogue figure as the middle of a band, then correct it on the first part: if the chips come off blue or the spindle load sits above roughly 80%, come down; if the finish is smeared and the chips are thin and stringy, come up. Write down what actually worked — that shop-specific number beats any published value.
Surface speed (cutting speed) is the relative velocity between the cutting edge and the workpiece surface. It is measured in surface feet per minute (SFM) in imperial shops and metres per minute (m/min) in metric shops.
| Input | Converted value |
|---|---|
| 50 SFM | 15.24 m/min |
| 100 SFM | 30.48 m/min |
| 150 SFM | 45.72 m/min |
| 200 SFM | 60.96 m/min |
| 300 SFM | 91.44 m/min |
| 400 SFM | 121.92 m/min |
| 500 SFM | 152.40 m/min |
| 600 SFM | 182.88 m/min |
| 800 SFM | 243.84 m/min |
| 1000 SFM | 304.80 m/min |
| 25 m/min | 82.02 SFM |
| 50 m/min | 164.04 SFM |
| 75 m/min | 246.06 SFM |
| 100 m/min | 328.08 SFM |
| 150 m/min | 492.13 SFM |
| 200 m/min | 656.17 SFM |
| 250 m/min | 820.21 SFM |
| 300 m/min | 984.25 SFM |
SFM is standard in the United States where imperial units dominate machine shop practice. Metric countries (Europe, Asia) use m/min. The conversion factor is 1 m/min = 3.28084 SFM.
Surface speed depends on the workpiece material and cutting tool material. Carbide in mild steel: 150-300 m/min (490-980 SFM). Carbide in aluminium: 300-600 m/min (980-1970 SFM). HSS in steel: 20-40 m/min (65-130 SFM).
Excessive surface speed generates excessive heat at the cutting edge, leading to rapid flank wear, built-up edge, poor surface finish, and potential insert failure. Reduce speed by 15-20% if you see burning or discoloration.
Enter your tool or workpiece diameter and RPM to get the surface speed in both m/min and SFM. Alternatively, work backwards from a target surface speed to find the required RPM.
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Use the calculator freely. If the result points to a tooling or process problem, we can source the exact carbide tooling you need from vetted factories in China. Compare factory-direct pricing.
Before you commit to a spec, it helps to know what the market pays for it. These are real, publicly listed factory prices — not a quotation, and not a guess.
We source the tool families below direct from vetted Chinese factories, matched to the material and tolerance you just worked out. Every batch ships with its material certificate and dimensional record.
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CONVERTING SFM TO M/MIN? Unit mistakes cost you a round of quotes; grade mistakes cost you a production run. On the second point, see how a grade claim is verified before ordering.
We source carbide cutting tools from China for job shops. We do not own a factory, which is why we can quote your drawing against two or three plants that actually run your material.
Cutting formulas with the units worked through · Speed and feed starting points for all six ISO material groups · How to read a carbide grade past its ISO code. 12 pages.
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