How To Convert Milligrams Per Liter To Parts Per Million

"Parts per million" sounds like a small quantity and it is. One part per million (ppm), for example, is the equivalent of one inch in a distance of 16 miles, one second in a little more than 11 days or one car in bumper-to-bumper traffic stretching all the way from Cleveland to San Francisco. Milligrams per liter (mg/L) is another unit scientists use to express small quantities. Converting from one to the other is perfectly simple.

Step 1

Write the quantity in milligrams per liter that you want to convert to parts per million using the correct units. For example, you write "7 mg/L."

Step 2

Multiply the number you have written by 1. For example, 7 x 1 = 7.

Step 3

Write your answer with the correct units as parts per million. For example, you write "7 mg/L = 7 ppm."