abbreviation

PPM

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PPM (abbreviation) means Parts per million: a measure of the concentration of a substance, equal to one unit of it for every million units of the whole. Example: “Atmospheric carbon dioxide has passed 420 ppm.”

abbreviation

scientific Parts per million: a measure of the concentration of a substance, equal to one unit of it for every million units of the whole.

"Atmospheric carbon dioxide has passed 420 ppm."

"The filter brought chlorine down to under 0.5 ppm."

technology Pages per minute: the rated printing speed of a printer.

"It's a workhorse laser printer rated at 40 ppm."

engineering, facilities Planned preventive maintenance: scheduled servicing carried out to stop equipment failing rather than in response to a fault.

"The boilers are on a quarterly PPM schedule."

How to Use PPM

Learner’s notes

In plain EnglishHow much of something there is in a million parts of a mixture — used for very small amounts.

When to use it

Written in lower case in scientific contexts (ppm) and often capitalised elsewhere.

Memory tip

For dilute water solutions, 1 ppm is about 1 milligram per litre, which makes lab results easy to convert.

Trace the full origin ↓

Easily confused with

ppb mg/L percent →

Common pairings

parts per million CO2 in ppm measured in ppm ppm concentration

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Test yourself on “PPM” A quick quiz — meaning, synonyms & usage →

Fill the Gap

Can you complete this real example?

Atmospheric carbon dioxide has passed 420 _____.

Etymology

An initialism; each sense abbreviates a different phrase.

Origin: English

Frequently Asked Questions

What is the difference between ppm and percent?

Both express a proportion. One percent is one part in a hundred; one ppm is one part in a million. So 1 percent equals 10,000 ppm. Ppm is used when concentrations are too small for percentages to be readable.

How do you convert ppm to mg/L?

For substances dissolved in water at normal temperature, 1 ppm is equal to 1 mg/L, because a litre of water weighs about a kilogram. The equivalence does not hold for gases or for liquids of very different density.

What is the difference between ppm and ppb?

Ppb means parts per billion, a thousand times smaller than parts per million. Ppb is used for trace contaminants such as heavy metals in drinking water, where ppm figures would be a long string of decimal places.