Fractional Inch to Decimal Equivalent Chart

Convert fractional inch measurements to decimal inches and millimeters for engineering applications

Fractional to Decimal Inch Conversion Chart

Fractional Inch Decimal Inch Millimeters (mm)
1/640.01560.396
1/320.03130.794
3/640.04691.191
1/160.06251.588
5/640.07811.984
3/320.09382.381
7/640.10942.778
1/80.12503.175
9/640.14063.572
5/320.15633.969
3/160.18754.763
1/40.25006.350
3/80.37509.525
1/20.500012.700
5/80.625015.875
3/40.750019.050
7/80.875022.225
11.000025.400

About Fractional Inch to Decimal and Metric Conversions

This comprehensive fractional inch to decimal equivalent chart provides precise conversions between fractional inches, decimal inches, and millimeters (mm). It serves as a vital reference for engineers, machinists, fabricators, and designers working with both imperial and metric measurement systems in manufacturing, machining, and construction.

Accurate measurement conversion is essential for ensuring dimensional consistency, proper component fit, and tolerance control in engineering and fabrication. This chart eliminates conversion errors when switching between imperial and metric systems, supporting precise calculations for drilling, milling, and assembly operations.


Fractional to Decimal Conversion Definitions


Engineering and Manufacturing Applications

The fractional to decimal conversion chart is widely used across mechanical design, CNC machining, woodworking, and metal fabrication. It assists professionals and students in:


By referencing this inch-to-decimal and millimeter conversion guide, engineers and technicians can maintain accuracy across design stages, reduce rework, and ensure measurement uniformity in both imperial and metric-based projects. It remains an essential reference for precision-driven industries.