Three of the most common types of measurement that people do are measurement of distance, area, and time, so those are the three discussed in this article.. Keep reading for more on systems of measurement and conversions.

Measurement is a very important concept in our world. We measure the height and weight of children to make sure they are growing properly. We measure our waists and leg lengths in order to purchase pants, slacks, or trousers that will fit properly. We measure ingredients to make recipes, furniture to be sure that it will fit in our homes, and the distance between seeds in gardens to make sure that each plant will have sufficient room to grow.

We refer to measurement even in the course of our entertainment. When we take a vacation, we plot out the distance to our destination. When we watch football, we wait to see the measurement on the field to see if our favorite team got the first down they were hoping for. For more about measurement and how we use it, read on.

Systems of Measurement

The two most commonly used systems of measurement in the United States are U.S. Customary Units and the Metric System, also called the International System of Units (SI). The first, also referred to as standard units are the units most used in the United States. SI is sometimes used alongside. Conversions from system to system are available in dictionaries, which one might expect because of the sort of reference it is, and sometimes in cookbooks, which makes them more international.

While SI is based on divisions of ten, the standard system is built on divisions that vary depending on what's being measured. For example, let's make a few simple comparisons:

  • A meter is made up of 100 centimeters, while a yard is made up of 36 inches.
  • A liter is made up of 1000 milliliters, while a quart is made up of 32 ounces.
  • A kilogram is made up of 1000 grams, while a pound contains 16 ounces.

The standard system has the advantage of familiarity, but you can see, just from those three examples, that the SI system has some distinct advantages in presenting a consistent

The Measurement of Distance

Distance measurements in the SI system are in millimeters, centimeters, meters, and kilometers, and in the standard system are in inches, yards, and miles. Some of the tools used are rulers, meter and yard sticks, measuring tapes, and in cars, odometers.

Here is how the distance measurements in standard units and SI compare:

Unit

Conversion

New Unit

Inches

25.4

Millimeters

Millimeters

0.0393700787

Inches

Yards

.9144

Meters

Meters

1.0936133

Yards

Miles

1.609344

Kilometers

Kilometers

0.621371192

Miles

Note that for your purposes, you may wish to round these numbers. For more information about rounding, see the article “Rounding Numbers.”

The Measurement of Area

Area measurements in the SI system are in square centimeters, square meters, and hectares, which are the equivalent of 10,000 square meters. In the standard system, area measurements are in square inches, square yards, and square miles. Since area is computed by multiplying two distances together, the same tools of measurement are used for area as for distance.

Here is how the area measurements in standard units and SI compare:

Unit

Conversion

New Unit

Square Inches

6.4516

Square Centimeters

Square Centimeters

0.15500031

Square Inches

Square Yards

0.83612736

Square Meters

Square Meters

1.19599005

Square Yards

Square Miles

258.998811

Hectares

Hectares

0.00386102159

Square Miles

For most everyday purposes, you will not need to use conversions with this many decimal places, and you may wish to round the numbers.

The Measurement of Time

Like the standard system for distance, the measurement of time has some of the same irregularity of unit relationships: that is, we're not working in multiples of 10. Small amounts of time are mostly measured by clocks and watches or one kind or another, but there are also sundials and calendars used to keep track of time. Here is how the units of time are related:

  • 60 seconds in a minute
  • 60 minutes in an hour
  • 24 hours in a day
  • 7 days in a week
  • 28, 29, 30, or 31 days in a month
  • 12 months in a year
  • 365.242199 days in a year

In most cases, 365 days in a year - or 366 in leap year - will do just fine.