Machining Time Calculator

Cutting time from length, feed, and passes: per-pass and total minutes, with approach distance built in — the floor of your cycle time.

Calculator

Cut length (in) Tool travel along the part. Facing a 6 in part? That is a 3 in radius cut.

Feed rate (IPM) From speeds and feeds: IPM = RPM × chip load × flutes (milling).

Passes Cutting strokes that cover depth or width at this feed.

Approach distance (in) Entry/exit air travel. Rule: about half the cutter diameter.

About this calculator

This machining time calculator turns a speeds-and-feeds result into minutes: how long the tool spends in the cut, per pass and in total. Get the feed rate from the speeds and feeds calculator first; tapping operations run on the tapping torque calculator.

Calculation Results

1.10 min

Total cutting time · 66 s · per pass 0.55 min (33 s)

Formula: t = (L + approach) / feed × passes

(10 + 0.1) / 18.3 × 2 = 1.10 min. Cutting time is the floor of cycle time — tool changes and loading are extra.

How to use this result

Compare per-pass time against what the job quoted: if cutting time alone busts the takt, no amount of faster loading saves it — the fix is feed, passes, or a different cutter. For quoting, add your measured tool-change and load times on top; shops typically add 15–40% over pure cutting time on second-operation work.

Continue Your Calculation

Time depends on feed — set the feed first if you have not yet.

Speeds & feeds →

Cutting time chart (min per pass, 0.1 in approach)

Time per pass = (length + 0.1) / feed. Multiply by pass count for total cutting time.

Cut length	5 IPM	10 IPM	15 IPM	20 IPM	30 IPM
2 in	0.42	0.21	0.14	0.11	0.07
6 in	1.22	0.61	0.41	0.30	0.20
12 in	2.42	1.21	0.81	0.60	0.40
18 in	3.62	1.81	1.21	0.91	0.60
24 in	4.82	2.41	1.61	1.21	0.80

Machining time formula

Per pass: t = (L + approach) / feed. For a 10 in cut at 18.3 IPM with 0.1 in approach: 10.1 / 18.3 = 0.55 min (33 s).

Total cutting time: T = t × passes. Two passes: 0.55 × 2 = 1.10 min = 66 s.

Where feed comes from: milling IPM = RPM × chip load × flutes; drilling and turning IPM = RPM × feed/rev. Feed rate is the whole game in time estimation — a 20% feed increase cuts time by 17%.

Feed rate setup: speeds and feeds calculator. Motor torque at that RPM: motor torque calculator.

Cutting time vs cycle time

Cutting time is only tool-in-material motion. What the shop floor calls cycle time stacks more on top:

Component	Typical magnitude	In this calculator?
Cutting (tool in material)	seconds to minutes	Yes — the output
Rapid positioning moves	0.5–5 s each	No — add manually
Tool change (mill/lathe)	2–10 s (ATC) to 60 s+ (manual)	No — add manually
Part load / unload / clamp	10 s (vise) to minutes (fixturing)	No — add manually
Dwell / spindle accel	< 1 s	No — usually negligible

A useful quoting heuristic for small shops: quote 130–150% of total cutting time for simple vise work, and more when fixturing is exotic. The ratio shrinks on long cuts and grows on many-short-features parts.

Frequently Asked Questions

How do you calculate machining time?

Time per pass = (length + approach) / feed. Example: 10 in at 18.3 IPM with 0.1 in approach = 10.1 / 18.3 = 0.55 min. Total = per-pass × passes = 1.10 min for two passes.

Is cutting time the same as cycle time?

No. Cutting time is tool-in-material only. Cycle time adds rapid moves, tool changes, load/unload, and dwell. Cutting time is the floor — on simple jobs it dominates, on feature-dense parts the overhead can exceed it.

Do multiple passes multiply the time linearly?

Yes at constant feed — each pass repeats the same stroke. Doubling depth usually doubles passes, which is why roughing at higher feed and fewer passes often beats many light passes: fewer strokes at higher IPM.

What is approach distance and how big should it be?

Air travel while the cutter enters and exits. Use about half the cutter diameter for milling entry plus a margin: 0.1 in suits small tools, a 2 in face mill can need 1 in+. Underestimating approach is the classic cause of "program runs longer than quoted".

Where does the feed rate number come from?

From the speeds and feeds calculator: IPM = RPM × chip load × flutes for milling, RPM × feed/rev for drilling and turning. RPM comes from material surface speed and cutter diameter.

How long does a tapping operation take?

Tapping cuts in and out: time = 2 × depth / (pitch × RPM). A 1 in deep 1/4-20 tap at 917 rpm feeds 45.8 IPM (20 tpi × 917 / 60 ≈ 45.8 IPM), so 2 / 45.8 ≈ 2.6 s of cutting. RPM rationale lives on the tapping torque calculator.

Does depth of cut change the machining time?

Not directly — the formula only sees length, feed, and passes. Depth enters indirectly: deeper stock needs more passes and sometimes lower feed. Change those inputs and the time follows.

How do I calculate in metric units?

Same structure in mm: time = (length + approach) / feed. A 250 mm cut at 460 mm/min = 0.54 min — the same job as the 10 in example, since 10 in = 254 mm and 18.3 IPM = 465 mm/min.

Review & sources

Reviewed: CalcPanel Machining Team

Updated: 2026-11-10