Compute material removal rate (MRR) — the volume of metal removed per minute — for
turning, milling, and drilling. Results in
in³/min, cm³/min, and mm³/min, plus a machining time estimator from
volume ÷ MRR. 100% in-browser — no data leaves your device.
Metal removal rate, not data removal or hair removal: this is a machining/manufacturing calculator.
MRR calculator
Pick an operation, enter your cutting parameters, and press Calculate.
All three formulas follow from the same idea: removal rate = (area of the chip cross-section) × (how fast that section advances). In turning the cross-section is depth × feed-per-rev and it advances at cutting speed πDN; in milling it is width × depth advancing at table feed; in drilling it is the drill's circular area advancing at penetration feed.
Typical cutting-parameter starting values
Typical starting values for planning — not absolute recommendations. Always verify against your tool manufacturer's data and Machinery's Handbook.
Material
vc turning (SFM)
vc milling (SFM)
Feed turning (ipr)
Chip load milling (ipt)
Starting ranges compiled from standard published carbide tooling tables (Machinery's Handbook and manufacturer speed/feed charts). Conservative planning values; coated carbide grades and rigid setups run higher.
Frequently asked questions
What is the material removal rate formula?
Material removal rate (MRR) is the volume of material removed per unit of time, also called the metal removal rate formula in shop literature. The turning material removal rate formula is MRR = pi x D x d x f x N, where D is the workpiece diameter, d is the depth of cut, f is the feed per revolution, and N is the spindle speed in RPM — the mrr turning formula pi D d f N that most shops memorize first. It can also be written as MRR = v_c x a_p x f_n, where v_c is the cutting speed. For milling the formula is MRR = a_e x a_p x v_f, and for drilling it is MRR = (pi/4) x D^2 x v_f.
How do you calculate material removal rate in turning?
This material removal rate calculator turning mode shows how to calculate material removal rate in a turning operation: the material removal rate in turning operation formula is MRR = pi x D x d x f x N. Example with this mrr calculator turning mode: a 2 inch diameter bar, 0.1 inch depth of cut, 0.01 inch per revolution feed, and 500 RPM gives MRR = pi x 2 x 0.1 x 0.01 x 500 = 3.1 in^3/min, which equals 51.5 cm^3/min — a metal removal rate calculator lathe-side result you can verify by hand. All length inputs must share the same unit for the result to be correct.
What is the MRR formula for milling?
The mrr formula milling shops use — the standard material removal rate milling formula — is MRR = a_e x a_p x v_f, where a_e is the radial width of cut (stepover), a_p is the axial depth of cut, and v_f is the table feed rate. Example: a 0.5 inch width of cut, 0.25 inch depth of cut, and 20 inch/min feed gives MRR = 0.5 x 0.25 x 20 = 2.5 in^3/min (41.0 cm^3/min). Use the milling tab of this milling mrr calculator for metric inputs.
How do you calculate material removal rate for drilling?
For drilling, material removal rate is MRR = (pi/4) x D^2 x v_f, where D is the drill diameter and v_f is the penetration feed rate (how fast the drill advances per minute). Example: a 0.5 inch drill feeding at 10 inch/min removes (pi/4) x 0.5^2 x 10 = 2.0 in^3/min (32.2 cm^3/min). Note that v_f here is the linear feed rate, not the feed per revolution.
What units is material removal rate measured in?
Material removal rate is a volume per time. Common units are in^3/min (cubic inches per minute) in imperial shops, and cm^3/min or mm^3/min in metric shops; the material removal rate unit cm3/min is the metric standard most shops quote. Conversions: 1 in^3/min = 16.387064 cm^3/min = 16,387.064 mm^3/min, and 1 cm^3/min = 1,000 mm^3/min. This calculator shows every result in all three units at once.
How do you convert in^3/min to cm^3/min?
Multiply by 16.387064, because one cubic inch equals exactly 16.387064 cubic centimeters. For example, 2.5 in^3/min x 16.387064 = 41.0 cm^3/min. To go from cm^3/min to mm^3/min, multiply by 1,000. The unit converter in this tool applies these exact factors, so a material removal rate unit conversion from cm3/min to mm3/min or in3/min is exact.
How is machining time calculated from MRR?
Machining time is simply the volume to remove divided by the material removal rate: t = V / MRR, which is exactly what the machining time calculator tab computes. The volume and the MRR must be in matching volume units first. Example: removing 100 in^3 at 2.5 in^3/min takes 100 / 2.5 = 40.0 minutes (0.7 hours). Use the machining time tab to enter any volume unit and any MRR unit; the tool converts automatically before dividing.
What is the difference between material removal rate and cutting speed?
The material removal rate vs cutting speed question comes up often. Cutting speed (v_c, in SFM or m/min) is how fast the cutting edge moves through the material, while material removal rate is the resulting volume removed per minute. They are related but not the same: in turning, MRR = v_c x a_p x f_n, so the same cutting speed gives a higher MRR with a deeper cut or a heavier feed. Cutting speed mainly drives tool life; MRR mainly drives cycle time.
Turning MRR worked example
Workpiece diameter D = 2 in, depth of cut d = 0.1 in, feed f = 0.01 in/rev, spindle N = 500 RPM. MRR = pi x 2 x 0.1 x 0.01 x 500 = 3.1 in^3/min = 51.5 cm^3/min. Equivalently, cutting speed v_c = pi x 2 x 500 = 3,141.6 in/min (261.8 SFM), and MRR = v_c x d x f = 3,141.6 x 0.1 x 0.01 = 3.1 in^3/min. Both forms agree.
Milling MRR worked example
Width of cut a_e = 0.5 in, axial depth a_p = 0.25 in, feed rate v_f = 20 in/min. MRR = 0.5 x 0.25 x 20 = 2.5 in^3/min = 41.0 cm^3/min. If the part requires removing 100 in^3 at this rate, machining time is 100 / 2.5 = 40.0 minutes. Increase a_e, a_p, or v_f to raise MRR and shorten cycle time.
Drilling MRR worked example
Drill diameter D = 0.5 in, penetration feed v_f = 10 in/min. MRR = (pi/4) x 0.5^2 x 10 = 2.0 in^3/min = 32.2 cm^3/min. A larger drill or a faster penetration feed raises MRR quadratically with diameter, so drill diameter is the strongest lever on drilling material removal rate.
Where can I find typical cutting parameters for MRR calculations?
The reference table on this page lists typical starting values of cutting speed, feed per revolution, and chip load for common materials (aluminum, mild steel, stainless steel, cast iron, brass, titanium). These are typical starting values for planning, not absolute recommendations: always verify against your tool manufacturer's data and Machinery's Handbook. This tool computes material removal rate (volume per time) only; for RPM, SFM, and chip-load solving, use a speeds and feeds calculator such as speeds-feeds-lab.
Scope note: this tool computes material removal rate (volume per time) for turning, milling, and drilling. It does not solve speeds & feeds (RPM, SFM, chip load) — for that see our speeds and feeds lab.
Data sources
Machinery's Handbook — standard MRR definitions: turning MRR = π × D × d × f × N; milling MRR = WOC × DOC × feed; drilling MRR = (π/4) × D² × feed.
Unit definitions: 1 in³ = 16.387064 cm³ (exact, international inch); 1 cm³ = 1,000 mm³.
Cutting-parameter ranges: typical carbide starting values from published manufacturer speed/feed charts; labeled as starting values, not absolute recommendations.
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