👤 By Why Calculator Team ✔ Reviewed by Matt Le (Founder of Why Calculator) 📅 Last Updated April 14, 2026
Drill Tip Length Calculator
| Unit | Tip Length |
|---|---|
| cm | – |
| inch | – |
| mm | – |
Disclaimer: While we strive to ensure the accuracy of our calculator tools, we cannot be held responsible for any damages or financial losses resulting from their use.
Ever wondered how long the tip of your drill bit actually is? With this easy-to-use Drill Tip Length Calculator, you can find out in seconds! Just enter your drill bit’s diameter, pick an angle, and get instant results in mm, cm, and inches. No more guesswork—get precise tip length effortlessly!
Whether you enjoy DIY projects or work as a professional, this tool helps you drill accurately. You can save time and get great results every time with just a few clicks!
How to Calculate Drill Tip Length?
The drill tip length is the vertical height of the tip of a drill bit, which depends on the drill bit diameter and the point angle. This calculation is essential for machinists, metalworkers, and DIY enthusiasts to ensure precision drilling.
Formula
The drill tip forms a conical shape, and its height can be determined using trigonometry:
L = D/2 × tan(θ/2)
Where:
- L = Drill Tip Length
- D = Drill Bit Diameter
- θ = Drill Point Angle (Common values: 118° or 135°)
- tan = Tangent function from trigonometry
Example 1: Drill Bit with 118° Point Angle
- Given: D = 10 mm, θ=118°
- Applying the formula:
L = 10/2 × tan(118/2)
L = 5 × tan(59°)
L = 5 × 1.6643
L ≈ 8.32 mm
Example 2: Drill Bit with 135° Point Angle
- Given: D = 10 mm, θ=135°
- Applying the formula:
L = 10/2 × tan(135/2)
L = 5 × tan(67.5°)
L = 5 × 2.4142
L ≈ 12.07 mm
Why Does Drill Point Angle Matter?
- The drill tip is not flat; instead, it has a conical shape based on the point angle.
- A larger drill point angle (e.g., 135°) creates a longer tip compared to a smaller angle (118°).
- Different materials require different angles:
Drill Tip Length Conversion Table:
| Diameter (mm) | Tip Length (118°) | Tip Length (135°) |
|---|---|---|
| 5.56 | 4.62 mm | 6.73 mm |
| 4.76 | 3.96 mm | 5.76 mm |
| 4.19 | 3.49 mm | 5.08 mm |
| 3.65 | 3.04 mm | 4.43 mm |
| 3.26 | 2.71 mm | 3.94 mm |
| 2.98 | 2.47 mm | 3.58 mm |
| 2.74 | 2.27 mm | 3.28 mm |
| 2.57 | 2.13 mm | 3.08 mm |
| 2.39 | 1.98 mm | 2.86 mm |
| 2.18 | 1.80 mm | 2.60 mm |
| 2.06 | 1.71 mm | 2.48 mm |
| 1.83 | 1.52 mm | 2.21 mm |
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