Drilling uses the same fundamental speed relationship as other rotating operations, but the feed side is normally expressed per revolution and the cutting environment is constrained by the hole depth, tool point geometry and chip evacuation. This page combines the RPM calculation with a feed-per-revolution check so the result is easier to translate into a CNC drilling cycle.
The first calculator converts a selected cutting speed and drill diameter into spindle RPM. The second converts programmed feed and RPM into feed per revolution. That separation is useful because drill manufacturers commonly publish feed in mm/rev or in/rev alongside a cutting-speed range. Hole depth, coolant, peck strategy and drill geometry are then used to decide whether the nominal condition fits the actual setup.
Start with the basic calculation, then go deeper
Run the smallest calculation that matches the job. Use the advanced version when additional process or machine variables need to be checked.
Quick Drilling Calculator
Run the common calculation for this machining task.
Spindle Speed
Enter the values you know. The result is calculated in your browser.
Calculation only. Verify toolmaker data, material grade, engagement, machine limits, workholding and actual cutting conditions before production.
Advanced Drilling Calculation
Add the main process variables and machine checks for a fuller calculation.
Feed Per Rev
Enter the values you know. The result is calculated in your browser.
Calculation only. Verify toolmaker data, material grade, engagement, machine limits, workholding and actual cutting conditions before production.
What this speed and feed calculator drilling calculates
Capture drill diameter, cutting speed, machine RPM limit, programmed feed and spindle RPM. Also note whether the drill is solid carbide, HSS, indexable, coated, through-coolant or intended for a particular hole-depth range. The mathematical inputs do not describe flute length, point angle, margin design, material grade, hole tolerance or machine runout, so keep those factors in the job record.
Formulas and unit handling
For drilling, metric RPM is RPM = (1000 × Vc) ÷ (π × D), while imperial RPM is RPM = (12 × SFM) ÷ (π × D). Feed rate is commonly expressed as F = RPM × f, where f is feed per revolution. If a cycle is programmed from feed per tooth instead, convert carefully and use the manufacturer’s terminology.
Metric RPM = (1000 × Vc) ÷ (π × D).Use the source unit shown in your tooling reference before converting.Imperial RPM = (12 × SFM) ÷ (π × D).Use the source unit shown in your tooling reference before converting.Drilling feed rate = RPM × feed per revolution.Use the source unit shown in your tooling reference before converting.Feed per revolution = feed rate ÷ RPM.Use the source unit shown in your tooling reference before converting.Step-by-step workflow
Technical context for this search
Drilling deserves its own calculation path because feed is commonly expressed per revolution and holemaking adds depth and chip-evacuation constraints. Start with the drill diameter and manufacturer cutting speed, calculate RPM, then connect RPM to the required feed per revolution. This makes the CNC value easy to audit: if RPM changes because diameter or surface speed changes, the linear feed changes with it when feed/rev is held constant.
The process context matters as hole depth increases. A condition that works in a shallow test hole may fail when chips have to travel farther through the flutes. Coolant delivery, through-coolant capability, drill point geometry, peck strategy and hole diameter all influence the result. These variables are outside the basic formula, so the page treats them as process checks rather than pretending the calculator can infer them.
When comparing a drill chart with a CNC program, preserve the chart’s exact terminology. One manufacturer may publish feed as mm/rev, another may provide a linear feed at a reference RPM, and another may specify a range by diameter or depth ratio. Converting the values is useful; silently mixing definitions is not. The first programmed hole should be treated as a verification point, especially when tool geometry or material condition differs from the reference data.
For troubleshooting, watch the sequence of symptoms rather than changing RPM immediately. Chip packing, squealing, drifting hole location, rising spindle load and excessive heat point to different parts of the process. Record the depth, coolant mode and hole result with the calculated condition. That gives you a technical basis for refining the setup instead of guessing from a single number.
Calculation audit checklist
| Check | What to verify |
|---|---|
| Operation check | Confirm that the job is actually drilling before entering values. The calculator pair on this page was selected for the speed and feed calculator drilling search intent, so switching to another operation may require a different feed convention. |
| Source check | Use the exact tooling or process reference behind speed and feed calculator drilling. Record the tool or process identifier, material and source units before converting anything; the site calculates from supplied values rather than selecting proprietary cutting data. |
| Input check | Verify the primary inputs used by the spindle-speed and feed-per-rev calculators. A field can be numerically valid while still being the wrong variable for the operation, especially when moving between chip load, feed/rev, feed rate and surface speed. |
| Unit check | Keep metric and imperial values separated through the calculation. Recheck diameter, cutting speed and feed units on the Speed and Feed Calculator Drilling page before accepting the result, and only round after the relationship has been verified. |
| Machine check | Compare the theoretical output with machine spindle, feed, travel and process limits. A calculated value is not a machine capability statement, and a controller limit can make the effective cutting condition different from the selected target. |
| Tool/setup check | Review tool condition, runout, overhang, workholding and coolant or lubrication where relevant to drilling. These variables are outside the arithmetic model but can dominate the actual cutting result. |
| First-cut check | Treat the first part or first hole as a validation event. Record chips, sound, load, finish and dimensional result alongside the calculated RPM/feed so later changes can be traced to evidence rather than memory. |
| Recordkeeping check | For repeat work, save the source reference, selected inputs, calculated values and final programmed values together. The Speed and Feed Calculator Drilling calculation then becomes a reproducible setup record instead of a one-time online number. |
Worked example
For a 10 mm drill at a nominal 80 m/min, the metric RPM calculation gives roughly 2,546 RPM. If the programmed feed is 200 mm/min, the corresponding feed per revolution is about 0.079 mm/rev. That value is only the mathematical conversion; the appropriate production feed still depends on the drill design, material, hole depth and manufacturer data.
Practical setup checks
Deep holes often expose weaknesses that are invisible in a short test hole. Chip evacuation becomes more important as depth rises, and a stable coolant path can matter more than a small change in RPM. Watch for chip packing, rising spindle load, wandering at entry, squealing, hole-size drift and excessive heat. Peck cycles are process decisions rather than universal fixes; the correct cycle depends on the drill and machine.
Common mistakes
- Using a milling chip-load formula for a drill without checking the toolmaker’s feed convention.
- Keeping RPM constant after changing drill diameter.
- Ignoring hole depth and chip evacuation.
- Assuming every drill needs the same peck cycle.
- Using a nominal feed value without checking the actual machine response.
Troubleshooting the calculated condition
For chip packing, first inspect coolant direction, hole depth, flute design and cycle strategy. For oversize holes, check runout, drill condition, entry stability and workpiece support. For a sudden increase in spindle load, look for poor chip evacuation, an incorrect material selection, worn margins or an overly aggressive feed. Change one major process variable at a time so the result remains traceable.
How to cross-check tool data
Use the drill manufacturer’s exact series and material table as the primary cutting-data reference. Many drilling products have recommended conditions tied to hole depth, coolant and drill geometry. This calculator should be treated as the arithmetic layer that converts those recommendations into machine values and verifies the internal consistency of RPM and feed.
Frequently asked questions
What feed unit should I use for drilling?
Most drilling references use feed per revolution, such as mm/rev or in/rev. The calculator can convert between feed rate and feed per revolution when RPM is known.
Why does drill diameter change RPM so much?
The surface-speed formula divides by diameter, so smaller drills require higher RPM to maintain the same cutting speed.
Does peck drilling automatically make a high feed safe?
No. Pecking changes chip evacuation and cycle behavior, but the cutting data must still match the drill, material and machine.
Should I cap RPM at the machine limit?
Yes. If the calculated RPM exceeds the machine capability, apply the machine limit and review the resulting effective cutting speed.
This page calculates relationships from the values supplied by the user. It does not inspect the machine, tool condition, workholding or material state. Verify production cutting values against the exact tooling reference and the actual setup before running the cut.