fraction (0–1)
Concentrationexact by definition
The fraction is the plain dimensionless ratio, running from 0 to 1, where percent runs from 0 to 100. One fraction is exactly 100 percent, and the factor of 100 is exact by definition. It is the form that belongs inside equations, since a formula expecting a fraction will silently give an answer a hundred times too large if fed a percentage.
Watch out: Efficiency, relative humidity and blowdown ratios are all quoted as percentages in conversation and used as fractions in arithmetic. Mixing the two is the most common dimensionless-unit error there is, and it is invisible in the units because both are dimensionless.
| 1 | 100 |
One fraction (0–1) in every concentration unit
| 1,000,000,000,000 | part per trillion (ppt) | |
| 1,000,000,000,000 | nanogram per liter (ng/L) | |
| 1,000,000,000 | parts per billion (ppb) | |
| 1,000,000,000 | microgram per liter (μg/L) | |
| 1,000,000 | parts per million (ppm) | |
| 1,000,000 | part per million by volume (ppmv) | |
| 1,000,000 | milligram per kilogram (mg/kg) | |
| 1,000,000 | milligram per liter (mg/L) | |
| 58,418 | grain per US gallon (as CaCO₃) (gpg) | |
| 1,000 | part per thousand (ppth) | |
| 1,000 | gram per liter (g/L) | |
| 100 | percent (%) | |
| 100 | percent by weight (% w/w) | |
| 100 | percent by volume (% v/v) | |
| 100 | percent weight per volume (% w/v) | |
| 1 | fraction (0–1) (fraction)this unit |
Solvers that use concentration