INTERACTIVE TURNING FORMULA CALCULATOR

Machining knowledge, made practical

Interactive Calculator

Turning Formula Calculator

Enter the known values on the left side of any equation below and click Solution to solve for the missing variable — speed, feed, metal removal rate, or theoretical surface finish.

DWorkpiece diameter at the machining point (in)
DOCDepth of cut (in)
IPRInches per revolution
SFMSurface feet per minute
IPMInches per minute
radNose radius of insert (in)
SURFACE FEET PER MINUTE (SFM)
×
× π/12 =
REVOLUTIONS PER MINUTE (RPM)
× (12/π) /
=
INCHES PER REVOLUTION FEED RATE (IPR)
/
=
INCHES PER MINUTE FEED RATE (IPM)
×
=
METAL REMOVAL RATE (in³/min)
× 12 ×
×
=
Ra FINISH (µin.)
(
/ (8 ×
)) × 333,333 =

Theoretical estimate only — not valid for round or wiper-style inserts.

RMS ROOT MEAN SQUARE (µin.)
((
/ (8 ×
)) / 3) × 370,000 =

Theoretical estimate only — not valid for round or wiper-style inserts.

Milling instead of turning? Use our Milling Formula Calculator, or decode an insert code with the Designation Chart.

Milling Calculator Insert Designation Chart Shop Turning Inserts
Reference: standard English-unit turning formulas. Results are theoretical estimates for planning purposes.

Ready to cut

Once the geometry is settled, the grade and the holder decide how long it lasts. Browse the turning line built for tight tolerances under aggressive feeds.

FM Carbide Turning Inserts → Tool Holders Boring Bars

Not sure which grade matches your material? Use the Grade Look-Up.