PPM Calculator

Parts per million, with the mg/L approximation named.

Parts per million, with the mg/L approximation named. Parts per million by mass is the solute mass over the total, times a million.

Written and maintained by Mohit PatelLast checked August 4, 2026How we build these

Solute mass

Solution mass

Parts per million

1,000 ppb · 0.000100%

ppm1

ppb1,000

Percent by mass0.0001000%

mg/L (aqueous approximation)1

Parts per million by mass is the solute mass over the total, times a million. The mg/L figure is an approximation that holds only for dilute aqueous solutions, where a litre weighs a kilogram — for concentrated solutions, or any non-aqueous solvent, the density differs and the two units part company. It is stated separately here rather than presented as the same number.

How the PPM Calculator works

Parts per million by mass is the solute mass over the total, times a million. The familiar equivalence of 1 ppm to 1 mg/L holds only for dilute aqueous solutions, where a litre weighs a kilogram — it is stated separately here rather than presented as the same number.

Also known as: parts per million calculator · ppm to percent converter · ppm to mg per litre · ppb calculator

Where to go next

The PPM question rarely arrives on its own. These are the ones that usually come with it:

Molarity Calculator — Moles per litre of solution — not of solvent.
Serial Dilution Calculator — Every step in the series, with the compounding shown.
Dilution Calculator — M₁V₁ = M₂V₂, with the diluent volume you actually need.
Speed Distance Time Calculator — Any one of the three from the other two, in four units.

Sources

Frequently asked questions

How do I calculate ppm?

Divide the solute mass by the total solution mass and multiply by 10⁶. One milligram in one kilogram is 1 ppm.

Is 1 ppm the same as 1 mg/L?

Only for dilute aqueous solutions, because a litre of water weighs about a kilogram. For concentrated solutions or any non-aqueous solvent the density differs and the two units part company.

How do I convert ppm to percent?

Divide by 10,000. 1 ppm is 0.0001%, and 10,000 ppm is 1%.

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