microliters

Microliter (symbol μL) is a unit of volume in the metric system. It denotes one millionth of a liter (10^-6 L). In practical terms, 1 μL is equal to 0.001 milliliters and 1 cubic millimeter (mm^3). Because 1 liter equals 1000 milliliters, a milliliter contains 1000 microliters, and conversely, a microliter is 0.001 of a milliliter. In cubic meters, 1 μL equals 1×10^-9 m^3.

Microliters are commonly used to measure small liquid volumes in laboratories, including biology, chemistry, biochemistry, and medicine. They are integral to sample preparation, DNA and RNA handling, enzymatic assays, and reactions that require precise, tiny volumes. Handling such volumes typically relies on micropipettes and microcentrifuge tubes designed for μL-scale measurements, which provide the accuracy and repeatability needed in experimental protocols.

The Greek letter mu (μ) denotes the micro- prefix. In plain text, μL is sometimes written as uL when the mu character is unavailable. Because the density of water is close to 1 g/mL at room temperature, 1 μL of water weighs about 1 mg, illustrating how volume relates to mass for liquids with known densities.