Reading the charts

on systems of units

Here is a small example, using English units of length:

		yard
	foot	3
inch	12	36
2.54 cm	30.48 cm	91.44 cm

At the top of each column is the name of a unit. The name is usually a link to a page about that unit, so it is whatever color links are on your system (conventionally, blue and underlined). The higher the name, the bigger the unit, so a yard is bigger than an inch.

Suppose you want to know how many inches there are in a yard. Start at "inch" and go horizontally across the inch row until you reach the yard column. The number there is 36. There are 36 inches in 1 yard. Or, for the same answer, you could go down the yard column until you hit the inch row.

At the bottom of the chart are one or more rows of conversion factors. Unlike the other cells in the chart, cells containing conversion factors have a white background and a green border. For example, find "foot". Go down the column, and 1 foot is 30.48 centimeters.

Some tips:

Several different units may be used in a row of conversion factors. For example, as the units described get bigger the conversion factor may go from millimeters to centimeters to meters to kilometers. Watch out for these changes!
The most accurate conversion factor we know of will be in the page about the unit. In the charts, there is only enough space for a few decimal places.
All the units in a chart measure the same thing, in this example, length. But a particular word may be the name of several different units that measure different things. That a unit name appears in a chart doesn't mean that that term doesn't have other meanings.