PPM Definition (Parts Per Million)

What PPM Means in Science

PPM or parts per million is a unit used to express dilute concentration of chemical solutions.
PPM or parts per million is a unit used to express dilute concentration of chemical solutions. Martin Leigh / Getty Images
by Anne Marie Helmenstine, Ph.D.
Updated July 24, 2017

PPM Definition: PPM stands for parts per million. It is commonly used to express concentration and temperature coefficients.
 

Also Known As: parts per million

Examples: 100 ppm is identical to 0.01%

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Helmenstine, Anne Marie, Ph.D. "PPM Definition (Parts Per Million)." ThoughtCo, Jul. 24, 2017, thoughtco.com/ppm-definition-606763. Helmenstine, Anne Marie, Ph.D. (2017, July 24). PPM Definition (Parts Per Million). Retrieved from https://www.thoughtco.com/ppm-definition-606763 Helmenstine, Anne Marie, Ph.D. "PPM Definition (Parts Per Million)." ThoughtCo. https://www.thoughtco.com/ppm-definition-606763 (accessed May 26, 2018).