How do you calculate cutting-time share?

Divide cutting (chip-making) time by total cycle time and multiply by 100. With 6.8 minutes of cutting in an 11.5-minute cycle, the share is 59.1 percent — meaning 40.9 percent of the cycle is non-cutting.

What is a good cutting-time percentage for CNC?

It depends on the part, but for production milling many shops target 60 to 75 percent in-cut. At 59.1 percent against a 65 percent target, this cycle sits 5.9 points short — a clear signal to attack rapids, tool changes, or air moves.

What counts as non-cutting time?

Rapid traverses, tool changes, dwell, probing, retracts, approach/clearance moves, and any pause where the tool is not removing material. Here it is the 4.7 minutes (40.9 percent) of the 11.5-minute cycle not making chips.

How do I increase cutting-time share?

Shorten rapids and retract heights, consolidate tool changes, combine operations into fewer setups, optimize lead-in/lead-out moves, and trim unnecessary dwell. Closing the 5.9-point gap to 65 percent on this part means cutting roughly 40 seconds of non-cutting time.

Is a higher cutting-time share always better?

Not always. A program can post a high share simply by running conservative feeds that keep the tool engaged longer. The goal is shorter total cycle time at a healthy share — always read this metric next to absolute cycle time, not in isolation.

Cutting time vs cycle time — what's the difference?

Cycle time is the full door-to-door clock for one part (11.5 min here). Cutting time is only the chip-making portion (6.8 min). The ratio between them — 59.1 percent — is the efficiency of the program.

CNC Machining calculator

Cutting Time vs Non-Cutting Time Calculator

Cutting-time share is the fraction of a CNC cycle that the tool is actually engaged and making chips, versus rapids, tool changes, dwell, probing, and air moves that add time but no metal removal. It is the single clearest lens on cycle efficiency: a low share means the machine is spending the cycle moving, waiting, and repositioning instead of cutting. Process engineers and CAM programmers use it to find where to claw back seconds — combining operations, tuning rapids, trimming retracts, or cutting tool changes. On a high-volume part, lifting this share a few points compounds into real capacity and lower per-part cost.

What this calculator does

Compare cutting minutes with total CNC cycle minutes to show how much of the program is actually removing material.
measuring the cutting-time share of a CNC program or production cycle
It computes cutting time as a percentage of total cycle time and the point gap to your target spindle-utilization share.

Formula used

Cutting-time share = cutting time ÷ total CNC cycle time × 100
Gap to target = cutting-time share - target cutting-time share

Inputs explained

Spindle cutting (chip-making) time:
Total CNC cycle time:
Target cutting-time share:

How to use the result

Use it when optimizing a cycle, benchmarking a program, or hunting for non-value-added time in high-volume work.
A high cutting-time share is not automatically good — conservative feeds can keep the spindle engaged longer while still leaving removal-rate gains on the table, so pair it with cycle time itself.

Current U.S. benchmarks

The producer price index for steel mill products stands at 348.53 (BLS, May 2026), up 6.7% from a year earlier. Quotes priced off last quarter's material cost miss this move.
The U.S. has 17,154 machine shops establishments employing about 223,303 workers (Census County Business Patterns, 2023).

Common questions

How do you calculate cutting-time share? Divide cutting (chip-making) time by total cycle time and multiply by 100. With 6.8 minutes of cutting in an 11.5-minute cycle, the share is 59.1 percent — meaning 40.9 percent of the cycle is non-cutting.
What is a good cutting-time percentage for CNC? It depends on the part, but for production milling many shops target 60 to 75 percent in-cut. At 59.1 percent against a 65 percent target, this cycle sits 5.9 points short — a clear signal to attack rapids, tool changes, or air moves.
What counts as non-cutting time? Rapid traverses, tool changes, dwell, probing, retracts, approach/clearance moves, and any pause where the tool is not removing material. Here it is the 4.7 minutes (40.9 percent) of the 11.5-minute cycle not making chips.
How do I increase cutting-time share? Shorten rapids and retract heights, consolidate tool changes, combine operations into fewer setups, optimize lead-in/lead-out moves, and trim unnecessary dwell. Closing the 5.9-point gap to 65 percent on this part means cutting roughly 40 seconds of non-cutting time.
Is a higher cutting-time share always better? Not always. A program can post a high share simply by running conservative feeds that keep the tool engaged longer. The goal is shorter total cycle time at a healthy share — always read this metric next to absolute cycle time, not in isolation.

Last reviewed 2026-05-12.