# Drill Feed and Speed Calculator

Optimize your CNC or manual drilling operations. Calculate the perfect spindle RPM, feed rate, and peck depth based on your tool and workpiece materials.

## What this calculates

Whether you operate a CNC machine or use manual equipment, setting the correct feed and speed is critical for clean holes and long tool life. Our drill feed and speed calculator is built specifically for drilling operations. Simply enter your drill diameter, workpiece material, and tool material (High-Speed Steel or Carbide). We will instantly calculate your optimal spindle RPM, feed per revolution (IPR), feed rate (IPM), safe peck depth, and dwell time.

## Inputs

- **Drill Diameter** (in) — min 0.001 — Drill bit diameter. Cutting speed scales inversely with diameter.
- **Workpiece Material** — options: Aluminum (300/800 SFM), Mild steel / 1018 (80/250 SFM), Alloy steel / 4140 (60/180 SFM), Stainless steel (40/130 SFM), Cast iron (60/200 SFM), Brass (200/400 SFM), Bronze (100/250 SFM), Copper (150/350 SFM), Titanium (25/80 SFM), Plastic (400/1000 SFM) — Material being drilled.
- **Drill Material** — options: HSS (high-speed steel), Solid carbide — HSS is the default for hand-drilling and most small shops. Carbide runs 2-3x faster but chips under interrupted cuts.
- **Hole Type** — options: Through hole, Blind hole, Deep hole (over 5x D) — Deep holes need pecking. Blind holes get a dwell at depth.
- **Hole Depth** (in) — min 0 — Total depth of the hole. Used to compute cycle time and peck count.

## Outputs

- **Spindle Speed** (RPM) — RPM = (SFM x 12) / (pi x D) for drilling.
- **Cutting Speed** (SFM) — Drilling SFM baseline for the material and tool combination.
- **Feed per Revolution** (in/rev) — Feed per revolution scaled to drill diameter.
- **Feed Rate** (in/min) — Linear feed rate = RPM x IPR.
- **Recommended Peck Depth** (in) — Safe peck depth for deep-hole cycles (about 1x drill diameter).
- **Recommended Dwell at Depth** (s) — Dwell time for blind holes to clean up the bottom before retract.
- **Approx Cycle Time** (s) — Approximate time at depth = hole depth / feed rate.

## Details

A Dedicated Tool for Drilling

This tool is not just a modified milling calculator. Drilling requires a unique approach because chip evacuation is harder at the tip, and coolant cannot easily reach the cutting edge deep inside a hole. As a result, drill Surface Feet per Minute (SFM) runs about 25% slower than end-mill SFM in the exact same material. Additionally, drill feed rates use inches per revolution (IPR) rather than inches per minute per tooth.

The Core Feed and Speed Equations

Our calculator relies on two primary formulas to determine your ideal machine settings:

- RPM = (SFM x 12) / (π x D)

- SFM is your cutting speed.

- D is your drill diameter in inches.

- Feed Rate (IPM) = RPM x IPR

- IPR is your feed per revolution, which usually ranges from 0.001 to 0.015 depending on the material and drill size.

Example Calculation:
If you use a 1/4-inch HSS drill on mild steel at 80 SFM, your calculation is (80 x 12) / (3.14 x 0.25). This gives you a spindle speed of 1,222 RPM. At a feed rate of 0.0045 IPR, your final feed rate is 5.5 IPM (1,222 x 0.0045).

Standard SFM Reference Chart

Different materials require completely different cutting speeds. Here are the baseline SFM speeds our calculator uses:

Workpiece Material
HSS Drill SFM
Carbide Drill SFM

Aluminum
300
800

Plastic
400
1,000

Brass
200
400

Mild Steel (1018)
80
250

Alloy Steel (4140)
60
180

Cast Iron
60
200

Stainless Steel
40
130

Titanium
25
80

Peck Drilling and Dwell Times

The depth of your hole dictates how you should run the drill:

- Shallow Through Holes: For holes up to three times your drill diameter, you can usually drill straight through without stopping.

- Blind Holes: If the hole does not go all the way through the material, program a 0.5- to 1.0-second dwell at the bottom. This brief pause cleans up the bottom of the hole before the drill retracts.

- Deep Holes: For holes deeper than five times your drill diameter, you must peck-drill. A standard peck depth equals one drill diameter. You should reduce this peck depth further when working with sticky materials like titanium and stainless steel, as chips easily weld to the drill flutes.

Drilling vs. Milling Calculations

Never use a milling calculator to set up a drilling operation. Drills always run at a lower SFM than end mills to prevent the tool from overheating deep inside the workpiece. Drills also measure feed rates in IPR, which indicates the actual chip thickness created during one full revolution. Use this calculator for all your drilling needs, and use a dedicated milling calculator for your end-mill operations.

## Frequently Asked Questions

**Q: How do I calculate drill feed and speed?**

A: Enter your drill diameter, the material you are drilling into, and your tool type. We use standard machining formulas to output your ideal RPM and inches per minute (IPM).

**Q: Why do drills use IPR instead of IPM?**

A: Drills measure feed in inches per revolution (IPR) to indicate the actual chip thickness created during one full spin, ensuring the tool does not break deep inside the hole.

**Q: When do I need to use peck drilling?**

A: You should peck-drill any time your hole depth is greater than five times your drill's diameter. This clears chips out of the hole and prevents the tool from overheating.

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Source: https://vastcalc.com/calculators/construction/drill-feed-and-speed
Category: Construction
Last updated: 2026-04-21