Other Methods of conversion
The conversion chart is a popular device for making conversions between systems. Conversion charts are readily available from many manufacturers .However, most conversion chart give equivalents for whole millimeters or standard fractional inches. If you must find an equivalent. In this instance, knowing the common conversion factors and determining the equivalent mathematically is more efficient.
Several electronic calculators designed to convert directly from one system to another are available. Of course, any calculator can and should be used to do a conversion problem. The direct converting calculator does not require that any conversion constant be remembered. These constants are permanently programmed into the calculator memory.