The microlitre is a minute liquid volume that is part of the metric system of measures and which has been accepted into the International System of Units. The litre consists of one million microlitres. As a comparative measure, a single microlitre of water could sit on the head of a pin.

Symbol

The symbol used for this measure is µl or µL.

The microlitre in molecular biology

The microlitre is a key volume measure in molecular biology, in which discipline experiments are often conducted where sample volumes are measured in microlitres and much equipment is scaled for the manipulation of volumes on the scale of 1 to 1000 microlitres. Records of experimental procedures in molecular biology and publications of experimental results sometime suffer from the replacement of 'µl' by 'ml', the latter being the symbol for millilitre, which is widely used in molecular biology procedures in the same context as the microlitre.