Drilling Calculator
Calculate spindle speed, feed rate, and drilling time from drill diameter, cutting speed, and feed.
How it works
- 1Enter the drill diameter (mm), cutting speed Vc (m/min), feed per revolution (mm/rev), and hole depth (mm).
- 2The calculator applies N = 1000 × Vc ÷ (π × D) to find the required spindle speed in RPM, then multiplies by feed/rev to get the feed rate in mm/min.
- 3Drilling time is computed as hole depth ÷ feed rate, shown in both seconds and minutes for easy reference.
Use cases
- CNC machine setup — determine the correct spindle speed before drilling a new material or hole size.
- Manual drill press work — verify RPM settings match the recommended cutting speed for the drill bit and workpiece material.
- Cycle time estimation — calculate how long each hole takes to plan production schedules and tool wear intervals.
Frequently asked questions
How is spindle speed (RPM) calculated for drilling?
Spindle speed N = 1000 × Vc ÷ (π × D), where Vc is the cutting speed in m/min and D is the drill diameter in mm. For a 10 mm drill at 30 m/min: N = 1000 × 30 ÷ (π × 10) ≈ 955 rpm.
What is feed rate and how does it differ from feed per revolution?
Feed per revolution (mm/rev) is how far the drill advances in one spindle rotation — a material and tool property. Feed rate (mm/min) = RPM × feed/rev and is the actual table or quill speed used by the machine.
Why does drilling time matter in machining?
Drilling time = hole depth ÷ feed rate. Knowing this lets you estimate cycle times, plan tool-change intervals, and compare the productivity of different speed–feed combinations before cutting.
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