The ppm calculator works out parts-per-trillion, parts-per-million and parts-per-billion from percent. Enter what you have and the relationship is applied straight away, so you get the answer without working through the algebra yourself.
What Is the PPM Calculator?
The ppm calculator converts percent between the units you need, so you do not have to hunt for a factor and work it out longhand.
Conversion factors are where unit mistakes happen, and a mistake here tends to propagate silently into everything calculated from it afterwards.
How the PPM Conversion Works
Each conversion uses the exact factor defined for the unit, so the answer is right to the precision you would normally quote.
Convert at one end rather than at several. Converting to a common unit first and then back again introduces rounding that you then have to carry through the rest of the calculation.
Getting the Units Right
Check that the unit you are converting from is the unit you actually measured in. Similar-looking units, particularly gallons and litres or ounces and grams, are the usual source of a factor-of-ten error.
Write down both the value and its unit. A number without a unit is not a measurement, it is a guess.
A Worked Example
Working through an example, with percent set to 10, the calculator returns parts-per-million of 100,000, and permille of 100, and number of 0.1. Substitute your own figures and the same steps produce the same kind of answer.
Frequently Asked Questions
What do I need to work out parts-per-trillion?
Enter percent. The calculator then works through the relationship and reports parts-per-trillion, parts-per-million and parts-per-billion.
What does the ppm actually calculate?
It takes percent and converts them into parts-per-trillion, parts-per-million and parts-per-billion using the standard relationship for this problem. Each step is applied in turn, so every output is traceable back to the numbers you typed in.
How should I enter percent?
Use the value you actually have, in the unit shown next to the field. Enter every value in the same unit system. The calculator assumes the figures you supply are consistent, so it cannot correct a mistake that happens before the calculation starts.
Do I have to fill in every field?
Only the fields a particular result depends on. If you leave one blank, the results that need it simply show a note instead of a number, and everything else still works.
Is the answer exact?
It is as exact as the formula and the inputs allow. The method itself is the standard one for this problem, so the only sources of error are the figures you enter and the precision you ask for.