Material Removal Rate Calculator
Pick the operation, enter the engagement figures, and get MRR in cm³/min and in³/min — the number that sizes the spindle power.
Last updated: 2026-09-28
How the calculation works
- Milling multiplies the swept cross-section by the feed; turning multiplies surface speed by the same cross-section.
- The power implication: steel needs roughly 2–4 kW per cm³/min of MRR, aluminum 0.5–1 kW.
- Imperial in³/min shown for US machine-spec cross-reference.
Formula
milling: MRR = ap × ae × vf turning: MRR = Vc × ap × fn
| Symbol | Meaning | Unit |
|---|---|---|
MRR | Material removal rate | cm³/min |
ap, ae | Depth and width of engagement | mm |
Worked example
Interpreting the result
MRR is the productivity metric of roughing: everything else being equal, the shop that removes metal fastest at acceptable tool life wins on price. The limit is spindle power and rigidity, not courage — running MRR beyond the machine's real power stalls the spindle or snaps the tool. Finishing tolerates low MRR for surface quality; roughing should chase the machine's honest ceiling.
Assumptions
- Continuous engagement at the stated parameters.
- Specific cutting forces: steel ~2–4 kW per cm³/min, aluminum ~0.5–1 kW per cm³/min.
Limitations
- Does not include tool wear state, chip evacuation limits or chatter constraints.
- Drilling and boring MRRs follow different geometry.
Frequently asked questions
What is MRR in machining?
Material removal rate — the volume of metal removed per minute (cm³/min or in³/min). Milling: ae × ap × vf. Turning: Vc × ap × fn.
How much power does machining steel need?
Roughly 2–4 kW per cm³/min of MRR for steels (unit power ~2–4 kW/cm³/min). A 10 cm³/min roughing pass wants a 20–40 kW spindle.