General Purpose Hydrometers
Usually the density is determined, prefereably in the units g/cm³, kg/m³ and g/ml. With alcoholometers usually the content of alcohol by volume in ethanol-water mixtures are determined. Reference temperature is 20°C. Other reference temperatures are possible. Calibration is generally made for 'reading below', for non-transparent liquids also 'reading above'.
API gravity hydrometers measuring range from 0 upto + 101°API
Specific gravity hydrometers measuring range 0.650 upto 2.000
Dairy Hydrometers (Lactodensimeters)
Measuring scale 10, 20 or 30 °Bé. With/Without Thermometers
Saccharimeters for Sugar Solutions
Brix hydrometers - measuring range from 0 upto 90:1°Brix, thermometer 0+50:1°C, red or blue filling, reference temperature 20°C.
for the determination of the content of alcohol by volume in ethanol/water mixtures, reference temperature 20° C
Hydrometers for Special Application
e.g. hydrogen peroxide, vinegar, hydrochloride acid, sulphuric acid, sodium Hydroxide