Concentration Converter — 5 Units, Free & Instant

Convert between Concentration units. Choose from 5 different units including Percent, Per Mille, Parts per Million.

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Popular Conversions

ppm to % % to ppm ppm to ppb ppb to ppm ‰ to % ppm to mg/L mg/L to ppm

All Units

From	Percent (%)
Percent (%)	1
Per Mille (‰)	0.1
Parts per Million (ppm)	0.0001
Parts per Billion (ppb)	1e-7
Milligrams per Liter (water) (mg/L)	0.0001

From percent to ppb

Dimensionless concentration runs down a ladder of thousands: 1% = 10 ‰ = 10,000 ppm; 1 ppm = 1,000 ppb. Atmospheric CO₂ (~420 ppm), blood-alcohol per-mille limits and drinking-water contaminant caps (in ppb) all live on this ladder.

ppm and mg/L

Water testing reports mg/L, and for dilute aqueous solutions 1 mg/L ≈ 1 ppm — because a litre of water weighs a million milligrams. That identity is why aquarium and water-hardness charts use ppm and mg/L interchangeably.