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ppm Converter

Type a number, pick the unit it is written in, and press Convert to see that value rewritten in the other parts-per notations.

Convert between parts-per notations

Type a value into the Parts-per notation field and choose its unit from the Unit list: Decimal / Ratio (ratio), Percent (%), Per-mille (‰), Parts-per million (ppm), Parts-per billion (ppb) or Parts-per trillion (ppt).

Press Convert and the results appear in cards below the button, each showing the same quantity in one notation. Copy writes a result and its unit to the clipboard, and Clear resets the form.

About parts per million

ppm stands for parts per million, a way of writing a very small share of a whole as a ratio. Percent, per-mille, ppb and ppt are sibling notations for the same idea, each naming the share at a different size.

For instance, 1 ppm equals 0.000001 as a ratio, 0.0001 % as a percent and 0.001 ‰ as a per-mille value. The table below shows more conversions taken straight from this tool.

ppm conversion formula

Every notation restates the same ratio with a different unit, so the tool rewrites your number in all the result forms at once. Entering 10 with the Unit set to Percent gives 0.1 ratio, 10 %, 100 ‰ and 100000 ppm.

It works in either direction: entering 0.5 with the Unit set to ratio gives 0.5 ratio, 50 %, 500 ‰ and 500000 ppm.