Free Diametral Pitch (DP) Gear Calculator | Imperial Gear Sizing & CAD

Calculate and design imperial standard gears based on Diametral Pitch (DP). Diametral pitch represents the number of gear teeth per inch of pitch diameter (DP = Teeth / Diameter_inches). GearDXF handles full imperial calculations in inches with high precision and exports DXF and SVG geometry.

Key Features

• Supports standard imperial Diametral Pitches (8, 10, 12, 16, 20, 24, 32, 48 DP)
• Calculates Pitch Diameter, Addendum (1/DP), Dedendum (1.157/DP - 1.25/DP), and Outer Diameter
• Converts automatically between Imperial inches and Metric millimeters
• Real-time simulation of meshing imperial gear pairs
• Instant export to CAD-ready DXF and SVG files
• 100% free with no account or license fees

Frequently Asked Questions

Does a higher Diametral Pitch mean larger or smaller teeth?

Higher Diametral Pitch means SMALLER teeth. Because DP is teeth per inch, a 48 DP gear has tiny teeth, while an 8 DP gear has large, heavy-duty teeth.

How do I find pitch diameter from Diametral Pitch?

Pitch Diameter (inches) = Number of Teeth / Diametral Pitch. A 24-tooth gear with a 12 DP has a 2-inch pitch diameter.

What pressure angle is standard for imperial DP gears?

Older imperial machinery often uses a 14.5° pressure angle, while modern industrial imperial equipment predominantly uses 20°.