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A millivolt (mV) is one‑thousandth of a volt, while parts per million (PPM) describes extremely dilute concentrations in soil or water. Converting between these units by hand is tedious due to the tiny decimal values; for instance, 1 mV equals 11.000000 × 10⁻³ ppm. An online calculator simplifies the process.

Step 1

Open the free conversion tool at Free University’s Conversion of Units Calculator.

Step 2

In the “From” dropdown, select mV.

Step 3

In the “To” dropdown, choose ppm.

Step 4

Enter the millivolt value you wish to convert in the “From” field and click Submit. The result appears on the next page; for example, 99 mV converts to 9.900000 × 10⁻² ppm.

TL;DR (Too Long; Didn’t Read)

Use a calculator: multiply the millivolt value by 1.000000 × 10⁻³ to get ppm.