PPM to percent converter
PPM is used for water quality, gas concentration and fertiliser mixes; this converter turns it into an exact percentage.
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Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Enter concentration.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
1 ppm = one part in a million = 0.0001%. So percent = ppm ÷ 10,000, and ppb = ppm × 1000.
Example
Inputs: Concentration = 250 ppm. Result: Percentage: 0.025%; Decimal: 0.00025; Per mille: 0.25 ‰.
Limits and caveats
- This is a pure ratio and does not turn ppm into mg/L, which only holds for dilute water solutions.
- The basis is unchanged: ppm by volume gives percent by volume.
Questions about this tool
What is 1 ppm as a percentage?
It is 0.0001%, so 10,000 ppm equals 1%.
What share of air is carbon dioxide at 420 ppm?
It is 0.042% of the air by volume.
Is ppm the same as mg/L?
Only roughly, in dilute water where a litre weighs about a kilogram. It does not hold for gases or other liquids.