How Do I Convert Mg/l To Ppm?

4 Answers

Charlie Proofer Profile
Charlie Proofer answered
Mg/l stands for milligrams per litre and it is a unit of measurement of mass concentration that shows how many grams of a substance are present in one litre of a liquid or gaseous mixture. The unit milligrams per litre is often used in the field of medicine and when writing out prescriptions. Ppm stands for parts per million which means out of a million, just as percent means out of a hundred. This unit is used to express very dilute concentrations of a solution.

One ppm is the equivalent of 1 milligram of a substance per litre of water. A litre of water weighs 1 kilogram (kg) which is the equivalent of 1000 grams (g). And in case you didn’t know, 1 milligram (mg) is a thousandth of a gram. So one kilogram is the same as 1 million milligrams. So 180 mg/l equals 180 mg/kg which equals 180 mg/million mg which gives you 180 ppm.

If you are near a computer and don’t want to do the conversion sum in your head then there are websites on the Internet that you can access to do the calculation for you. This website: asks you to enter either the Mg/l value or the ppm value and it will convert it automatically for you. It will give you the answer to nine decimal places giving a very accurate answer. This method will give you better results that just doing it in your head. For example, if you use the website given to do the calculation stated in the previous paragraph (180mg/l to ppm) you will be given the answer 180.20561454 which is a much more accurate answer than the one you worked out in your head. Using an online convertor is the best way to get a good answer, rather than trying to calculate it in your head, especially if you have further sums to do. Although a pen and paper method is well worth learning for exams.
Richard Enison Profile
Richard Enison answered
Mg/l stands for milligrams per liter; ppm stands for parts per million (presumably by weight). Now a liter of water weighs 1 kg (killogram) by definition, which is a thousand grams. A milligram is a thousandth of a gram. Therefore, a kg is 1 million mg. So 182.5 mg/l = 182.5 mg/kg = 182.5 mg/million mg = 182.5 ppm.
thanked the writer.
Anonymous commented
Many thanks. It all makes sense now you have explained it. I shall get on with the home brew. Once again many thanks.
Silke Stahl Profile
Silke Stahl answered
How do I convert ppm to mg/l for a saline solution with an unknown density (density lies somewhere between 1.05 and 1.2 g/cc according to the salinity)?

I know that usually its:    Mg/l = ppm *density
thanked the writer.
Silke Stahl
Silke Stahl commented
It also helps me to know how to convert NaCl-Salinity (ppm) to Density. Then I could use that for calculating to mg/l. Charts are excisting for that, so there should also be a way to calculate it I guess.
Who knows how?

Thanks in advance :)

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