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ppb to ppm Converter

Parts per billion and parts per million both describe a very small share of a whole, and one billionth is a thousandth of one millionth. Type a ppb amount, press Convert, and the ppm figure appears in the card below the buttons.

What ppb and ppm mean

Neither unit measures a physical quantity on its own; both express a ratio. One part per million describes a single share out of a group of one million shares, while one part per billion describes one share out of a group of one billion shares.

A billion is one thousand times a million, so a billionth works out to a thousandth of a millionth. That is why the same ratio carries a much bigger number when it is written in ppb than when it is written in ppm.

ppb to ppm formula

To change parts per billion into parts per million, multiply the ppb figure by the factor 1/1000, which is the same as dividing it by 1000: x(ppm) = x(ppb) / 1000.

Worked through, 7000 ppb divided by 1000 comes to 7 ppm, and 250 ppb divided by 1000 comes to 0.25 ppm. To travel the other direction, multiply a ppm figure by 1000 and you are back in ppb.