Speed & Feed Calculator
Convert cutting speed (SFM) and chip load into spindle RPM and feed rate for any tool and material.
Using this calculator responsibly
The Speed & Feed calculator is an engineering aid for checking a shop-floor estimate before a setup, quote, or process review. Enter values in the units shown, confirm material properties against the applicable specification, and keep a record of the assumptions used. Calculator output does not override machine capacity, tooling limits, part requirements, or a qualified engineer's approval.
Before using a result in production, repeat the calculation with the extreme values allowed by the print or process window. Check that the selected material, thickness, geometry, and safety factor reflect the actual job. If a result approaches a press, die, fastener, or machine limit, stop and verify it with the equipment manufacturer or responsible engineer.
Inputs and results
Read every field label before entering data and avoid mixing inch and metric values. A useful result should be traceable to the job number, revision, material certification, and machine or tooling record. Treat warnings, invalid ranges, and unusual outputs as reasons to inspect the inputs rather than as values to work around.
Cutting speed (SFM) and the tool diameter set spindle RPM; RPM, chip load, and the number of flutes set the feed rate. Start from the material’s recommended SFM and chip load, then tune by sound and chip color.
Formula: RPM = (3.82 × SFM) / Ø; Feed (ipm) = RPM × Chip load × Flutes
Worked example
- A 0.500 in 4-flute end mill at 300 SFM, 0.002 in/tooth.
- RPM = 3.82 × 300 / 0.5 ≈ 2,292; Feed = 2,292 × 0.002 × 4 ≈ 18.3 ipm.