Shop drawings and tool catalogs mix inch and metric units, so conversions come up constantly. The inch and millimeter converters handle lengths, while SFM to meters per minute and back, and IPM to mm per minute, translate cutting speeds and feed rates for tools specified in the other system.

The RPM to SFM calculator turns a spindle speed back into a surface speed. PSI to bar, inch pounds to newton meters, Fahrenheit to Celsius, and fraction to decimal cover pressure, torque, temperature, and drill size conversions. Round only at the end to avoid stacking small errors.

One inch is exactly 25.4 millimeters, so a 0.5 inch tool is 12.7 mm. A surface speed of 100 SFM is about 30.48 meters per minute, since meters per minute equals SFM times 0.3048, and a feed of 20 IPM is 508 mm per minute. One bar is about 14.5 PSI, and one newton meter is about 8.85 inch pounds.

Temperature converts with F minus 32, times 5 over 9, to give Celsius. When converting several values in a chain, keep full precision until the final step and round only the result, so small rounding errors do not stack up.