Please help me converting 40 ppt to pg/mL. I have tried an online calculator and done it manually and there are differences. I`m aware that ppt can be used as parts per trillion or per thousand but I don´t understand where the difference is coming from. The calculator is http://www.endmemo.com/sconvert/pg_mlppt.php


  • 3
    $\begingroup$ You wrote that you did it manually. Could you please edit your question and show what you've done so far? That wound help to get an idea where the problem arises... $\endgroup$
    – Arsak
    Jan 9, 2020 at 22:03
  • $\begingroup$ Check out picotrillion.com $\endgroup$
    – Karsten
    Jan 9, 2020 at 23:10
  • $\begingroup$ By manually I mean thinking automatically 40 pg/mL is equal to 40 ppt . Thanks someone just confirmed that the online converter is broken so my calculation is ok. $\endgroup$ Jan 10, 2020 at 18:59

1 Answer 1


You are in luck. The converter is broken, so it gave you the wrong answer:

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It does fine with ppm and ppb, but conversions to and from ppt seem to be broken. A trillion can mean ten to the twelve (conventional), a lot (informal), or ten to the eighteen (dated, British) according to lexico.com.


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