Enter the concentration in micrograms per kilogram (µg/kg) into the converter to determine the equivalent concentration in parts per billion (ppb). For mass-based measurements, 1 µg/kg is exactly equal to 1 ppb.

ug/kg to ppb Converter

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µg/kg → ppb
ppb → µg/kg
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ug/kg to ppb Formula

The following formula is used to convert micrograms per kilogram to parts per billion on a mass basis.

ppb = µg/kg

Variables:

  • ppb is the concentration in parts per billion
  • µg/kg is the concentration in micrograms per kilogram
  • The relationship applies for mass-based concentration measurements

To convert µg/kg to ppb, copy the numerical value directly. This is because 1 microgram equals 10-6 grams and 1 kilogram equals 103 grams, so 1 µg/kg equals 10-9 g/g, which is exactly 1 ppb.

What is ug/kg to ppb?

Micrograms per kilogram (µg/kg) and parts per billion (ppb) are both used to describe very small concentrations of a substance in a sample. In laboratory reports, food testing, environmental analysis, and contaminant measurements, the same concentration may be written as either µg/kg or ppb depending on the reporting standard.

When the concentration is expressed on a mass-by-mass basis, the units are numerically identical. That means a sample containing 10 µg/kg of a compound also contains 10 ppb of that compound, and 250 µg/kg is the same as 250 ppb.

How to Convert ug/kg to ppb?

The following steps outline how to convert micrograms per kilogram to parts per billion.


  1. First, determine the concentration in micrograms per kilogram (µg/kg).
  2. Next, confirm that the concentration is being reported on a mass basis.
  3. Finally, copy the same numerical value as the concentration in parts per billion (ppb).
  4. Check your answer with the converter above.

ug/kg to ppb Conversion Table

The table below shows several common examples of µg/kg values and their equivalent concentrations in ppb.

Concentration (µg/kg)Equivalent in ppbNotes
1 µg/kg1 ppbExtremely low trace level
5 µg/kg5 ppbVery small concentration
10 µg/kg10 ppbCommon example value
50 µg/kg50 ppbModerate trace concentration
100 µg/kg100 ppbTypical regulatory-scale value
500 µg/kg500 ppbHigher trace-level concentration
1000 µg/kg1000 ppbEqual to 1 ppm

Example Problem

Use the following example to test your understanding of the conversion.

Concentration = 75 µg/kg

Equivalent concentration in ppb = 75 ppb

Since the conversion is one-to-one on a mass basis, the value remains the same.