It is much better to become thoroughly familiar with SI than to be forever bound to conversion tools and factors. And it isn’t that hard if one learns to “think in metric.” For example, a millimeter is about the size of a pinhead; a centimeter is about the width of your finger. When you stand up, your waistline is about a meter from the ground. A meter is a little bit larger than a yard.
A paper clip may weigh a gram, and a two-pound bag of brown sugar is a little less than a kilogram. A metric ton is a little bit larger than the U.S. ton.
A liter is a little bit larger than a quart. Five milliliters approximately equal one teaspoon. Kitchen measures are “as easy as pie” in the metric system.
Water freezes at 0 °C (Celsius) and boils at 100 °C. Certainly that makes more sense than the 32° and 212° in Fahrenheit. A spring day may be 10 °C. Your home thermostat, if set for 68 °F in winter, would be set for 20 °C. A warm summer day may be 30 °C. Normal body temperature is 37 °C.
Familiarize yourself with the metric system, and someday there will be no need or use for Web pages like this one!