Enter the concentration in nanograms per gram (ng/g) into the calculator to convert it to parts per billion (ppb) on a mass-by-mass basis. Because 1 ng/g equals 1 ppb for mass fractions, the calculator returns the same numeric value with the ppb unit label.
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ng/g to ppb Formula
The following formula is used to convert nanograms per gram to parts per billion when both units are expressed on a mass-by-mass basis.
ppb = ng/g
Variables:
- ppb is the concentration in parts per billion by mass
- ng/g is the concentration in nanograms per gram
To convert ng/g to ppb, use the same numerical value. This is because 1 nanogram per gram represents a mass fraction of 10⁻⁹, which is exactly 1 part per billion by mass.
What is ng/g to ppb?
Nanograms per gram (ng/g) and parts per billion (ppb) are both used to describe very small concentrations of a substance in a sample. In analytical chemistry and environmental reporting, these units are often interchangeable when the concentration is measured as mass of analyte per mass of sample. Since 1 ng equals 10⁻⁹ grams, a concentration of 1 ng/g corresponds to a 10⁻⁹ mass fraction, which is defined as 1 ppb.
This means that for solids such as soil, dust, food, sediment, or tissue, the conversion from ng/g to ppb is direct. The number does not change; only the unit label changes. In many water applications, the same relationship is used as an approximation when concentrations are being discussed on an equivalent mass basis.
How to Convert ng/g to ppb?
The following steps outline how to convert ng/g to ppb.
- First, determine the concentration in nanograms per gram (ng/g).
- Next, confirm that ppb is being used as a mass-by-mass concentration.
- Finally, copy the same numerical value and label it as ppb.
- After inserting the value and calculating the result, check your answer with the converter above.
Example Problem:
Use the following variables as an example problem to test your knowledge.
Value in ng/g = 10
Result in ppb = 10
Because the measurement is mass per mass, 10 ng/g is exactly equal to 10 ppb.
ng/g to ppb Conversion Table
The table below shows example conversions using the relationship ppb = ng/g for common sample types.
| Sample Type | Interpretation | 10 ng/g in ppb |
|---|---|---|
| General solid sample | Mass fraction by sample weight | 10 ppb |
| Water or dilute aqueous solution | Typically treated as equivalent on a mass basis | 10 ppb |
| Soil, sediment, or dust | Dry-mass concentration | 10 ppb |
| Food or biological tissue | Trace mass fraction in sample | 10 ppb |
Analytical laboratories may report low-level concentrations in either ng/g or ppb depending on reporting standards. When both units refer to a mass fraction, they are numerically identical. A value of X ng/g is simply X ppb by mass.
This conversion is especially useful in environmental chemistry, food testing, toxicology, and materials analysis, where trace concentrations are commonly reported in different but equivalent formats.