Tap Drill Depth Calculator
Calculate the required tap drill depth, hole depth, and tap drill size for various thread types. Enter the thread size, thread type, and thread depth percentage to get the required drilling dimensions.
0.00 mm
Recommended Tap Drill Size
Hole Depth: 0.00 mm
Tap Drill Depth: 0.00 mm
Thread Engagement: 0.00 mm
Tap Drill Depth: 0.00 mm
Thread Engagement: 0.00 mm
Tap Drill Depth Calculation
This tap drill depth calculator based on the drill size and hole depth for tapping threads.
Formulas:
Tap Drill Size = Thread Diameter - (Thread Pitch × 0.6495 × Thread Depth%)
Where:
- Thread Diameter = Nominal diameter of the thread (mm)
- Thread Pitch = Distance between threads (mm)
- Thread Depth% = Percentage of full thread depth (50-85%)
Hole Depth = Thread Length + Tap Lead (2-3 threads)
Tap Drill Depth = Hole Depth × 1.25 (for chip clearance)
Standard Tap Drill Sizes (Metric):
| Thread Size | Pitch (mm) | Tap Drill (mm) | Tap Drill (inch) | Thread Depth (%) |
|---|---|---|---|---|
| M3 | 0.5 | 2.50 | 0.0984 | 75 |
| M4 | 0.7 | 3.30 | 0.1299 | 75 |
| M5 | 0.8 | 4.20 | 0.1654 | 75 |
| M6 | 1.0 | 5.00 | 0.1969 | 75 |
| M8 | 1.25 | 6.80 | 0.2677 | 75 |
| M10 | 1.5 | 8.50 | 0.3346 | 75 |
| M12 | 1.75 | 10.20 | 0.4016 | 75 |
| M14 | 2.0 | 12.00 | 0.4724 | 75 |
| M16 | 2.0 | 14.00 | 0.5512 | 75 |
| M20 | 2.5 | 17.50 | 0.6890 | 75 |
| M24 | 3.0 | 21.00 | 0.8268 | 75 |
| M30 | 3.5 | 26.50 | 1.0433 | 75 |
Tap Drill Sizes (UNF):
| Thread Size | Pitch (mm) | Tap Drill (mm) | Tap Drill (inch) | Thread Depth (%) |
|---|---|---|---|---|
| 1/4-28 UNF | 0.907 | 5.50 | 0.2165 | 75 |
| 5/16-24 UNF | 1.058 | 6.90 | 0.2717 | 75 |
| 3/8-24 UNF | 1.058 | 8.50 | 0.3346 | 75 |
| 7/16-20 UNF | 1.270 | 9.90 | 0.3898 | 75 |
| 1/2-20 UNF | 1.270 | 11.50 | 0.4528 | 75 |
| 9/16-18 UNF | 1.411 | 12.90 | 0.5079 | 75 |
| 5/8-18 UNF | 1.411 | 14.50 | 0.5709 | 75 |
| 3/4-16 UNF | 1.588 | 17.50 | 0.6890 | 75 |
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