Which machines can use this cutting estimate?

Any gear cutting process that removes material at a measurable rate: hobbing, shaping, skiving, milling and broaching. Use the rate you measured on the same machine, material and tooth geometry, and keep the allowance in the same units, a percent of cutting time only.

Does the allowance cover tool changes?

Only if your measured allowance includes them. A broken hob or a mid-batch tool change costs far more than a percentage, so add planned tool-change events as separate hours rather than stretching the allowance percentage.

What if the batch is split across shifts?

The hours stay the same; only the calendar time changes. Two shifts at the same rate cut a 180 blank batch in the same hours, so compare the total with the target rather than one shift.

Why does the rate change the result so much?

Cutting hours divide the blank count by the rate, so a rate 20% lower adds about 25% more base hours. Test the rate on the actual material and hob before you commit the target, because a small error there dominates the allowance.

Bearings, Gears & Power Transmission calculator

Gear Cutting Cycle Time Calculator

Work out the cutting hours a batch of gear blanks needs at your demonstrated rate, then add the allowance for setup and inspection. The page checks the plan against the hours you have.

What this calculator does

Gear cutting hours for a batch, with the setup and inspection allowance called out and the plan checked against your target.

Formula used

Base cutting hours = gear blanks to cut ÷ verified cutting rate
Gear-cutting hours required = base hours × (1 + setup and inspection allowance ÷ 100)
Setup and inspection hours = gear-cutting hours required − base cutting hours
Hours over target = gear-cutting hours required − target cutting hours

Inputs explained

Gear Blanks to Cut: Gear blanks released to the cutting operation for this batch.
Verified Cutting Rate: Sustained rate proven on this material, hob and machine.
Setup and Inspection Allowance: Allowance from your time study for setup and in-process checks.
Target Cutting Hours: Hours the shift plan or order allows for this batch.

How to use the result

Best suited to quoting a hobbing or shaping job, sizing spindle hours for a gear order, checking a split release against a shift plan.
Covers cutting hours only: waiting, deburring, transport and outside operations are not included. One rate for the whole batch; a new hob or a harder heat-treat condition runs slower.

Current U.S. benchmarks

The U.S. has 21,668 machinery manufacturing establishments employing about 1,086,146 workers (Census County Business Patterns, 2023).

Common questions

Which machines can use this cutting estimate? Any gear cutting process that removes material at a measurable rate: hobbing, shaping, skiving, milling and broaching. Use the rate you measured on the same machine, material and tooth geometry, and keep the allowance in the same units, a percent of cutting time only.
Does the allowance cover tool changes? Only if your measured allowance includes them. A broken hob or a mid-batch tool change costs far more than a percentage, so add planned tool-change events as separate hours rather than stretching the allowance percentage.
What if the batch is split across shifts? The hours stay the same; only the calendar time changes. Two shifts at the same rate cut a 180 blank batch in the same hours, so compare the total with the target rather than one shift.
Why does the rate change the result so much? Cutting hours divide the blank count by the rate, so a rate 20% lower adds about 25% more base hours. Test the rate on the actual material and hob before you commit the target, because a small error there dominates the allowance.

Related guides

Last reviewed 2026-10-01.