Cutting Speed Calculator
SI
Imp
Imperial
Inputs
View results
Solve for
Choose whether the unknown is RPM or cutting speed.
Spindle RPM from cutting speed
Cutting speed from RPM
Diameter
(D)
Tool diameter for milling/drilling, or workpiece diameter for turning.
in
Cutting speed
(Vc)
Target cutting speed from a reference table or tooling recommendation.
SFM
Spindle speed
(n)
Actual spindle speed used to calculate surface cutting speed.
rpm
Results
Default result
Edit inputs
Spindle speed
(n)
382
rpm
Also computed
Cutting speed
(Vc)
100
SFM
Method notes
3 notes
RPM = cutting speed ÷ (π × diameter); cutting speed = RPM × π × diameter.
Use tool diameter for milling and drilling; use workpiece diameter at the cut for turning.
Recommended cutting speeds are starting points. Tool material, coating, coolant, rigidity and depth of cut all move the practical value.
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