How to Convert Units

Step-by-Step Guide

1. 1

   Step 1: Compare your two units.

   The two units must measure the same thing.
   
   For example, in the problem "convert 2 inches into centimeters," both inches and centimeters measure length.
   
   If your units measure two different things (like length and weight), you can't convert between them.
   
   People often get confused about length, area, and volume, which are three different things.
   
   Remember that "square" or "2" means area, and "cubic" or "3" means volume.
   
   You can also write this example as 2 in. = ? cm.
2. 2

   Step 2: Look up the conversion.

   Before you can do the math, you need to know how much larger one unit is than the other.
   
   If the conversion you find has many decimal places, round to the nearest significant digit.
   
   If you don't know what a significant digit is, round to the second or third digit.
   
   For example, if you need to convert 2 inches to centimeters, you need to know that 1 inch =
   2.54 centimeters. , Write this conversion as a fraction, including units.
   
   Put the unit you start with on bottom (the denominator), and the unit you're converting to on top (the numerator).For example, write
   2.54 cm/1 in..
   
   You can read this as "2.54 centimeters per inch". , Multiplying these two numbers together will give you your answer.
   
   To start this, write out the multiplication problem, with units after each value. 2 in. x
   2.54 cm/1 in. = ? , It's important to keep track of your units while you do this.
   
   Every unit in the equation should still be there during each step. 2 in. x
   2.54 cm/1 in. = (2 in x
   2.54 cm)/1 in. = (5.08 in. x cm.)/ in. , If a unit is on the top and bottom of the fraction, cross it out.
   
   Whatever you're left with should be your answer. (5.08 in. x cm.)/ in. =
   5.08 cm. , If your units don't cancel, start over and try again.
   
   You might have put the wrong half of the fraction on top.
   
   For example, if you multiplied 2 inch. x (1 in. /
   2.54 cm), your answer will have units of "in. x in. / cm," which doesn't make any sense.
   
   You realize the inches will cancel if you flip the fraction, so you try again with 2 inch x (2.54 cm / 1 in.).
3. 3

   Step 3: Write the conversion as a fraction.

4. 4

   Step 4: Write a multiplication problem with your original number and the fraction.

5. 5

   Step 5: Solve the multiplication problem.

6. 6

   Step 6: Cancel units that appear on top and bottom.

7. 7

   Step 7: Correct mistakes.

Detailed Guide

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