Milliliters to Microliters Converter
Common Conversions
| mL | µL |
|---|---|
| 0.001 | 1 |
| 0.002 | 2 |
| 0.005 | 5 |
| 0.01 | 10 |
| 0.02 | 20 |
| 0.05 | 50 |
| 0.1 | 100 |
| 0.2 | 200 |
| 0.5 | 500 |
| 1 | 1000 |
| 2 | 2000 |
| 5 | 5000 |
Why this conversion matters in chemistry
Reagent stocks live in mL — a 1 mL aliquot of an enzyme, a 5 mL aliquot of buffer — and the work happens in µL. A PCR reaction is 20 µL. An ELISA well takes 100 µL. Plating a bacterial culture might use 50 µL. Multiplying by 1000 is the bookkeeping that lets a 1 mL stock become twenty 50 µL aliquots, each one carrying the volume the pipette is actually rated for. The conversion is what keeps a notebook calculation from accidentally claiming you delivered a thousand times more enzyme than you did.
Formula
Where the factor comes from
Both units are the liter wearing a prefix, which makes this the shortest derivation in the volume set: milli is 10⁻³, micro is 10⁻⁶, and the ratio 10⁻³/10⁻⁶ = 10³ is the whole factor. The liter's own definition cancels on the way through and never has to be invoked at all — unlike mL to cm³, where two different unit constructions must be reconciled before anything else happens. Both prefixes are fixed by decision, so the 1000 is exact and permanent. The symbol earns a sentence of its own: µ is the micro sign, and the correct rendering is µL. Neither uL nor ul is right, and both are artifacts of an encoding that failed somewhere upstream.
Precision and significant figures
An exact factor hands the digits entirely over to the pipette. Air-displacement pipettes are specified as a percentage of the volume set, and that percentage worsens sharply toward the bottom of the range — commonly a few tenths of a percent near full scale and several percent at the low end. So 200 µL delivered from a 20–200 µL instrument is a better number than the same 200 µL off a 100–1000. Below roughly 5 µL, tip retention and evaporation start to outweigh the specification. Gravimetry settles any argument: 1 µL of water weighs close to 1.00 mg at 20 °C, so a balance reading to 0.01 mg resolves a hundredth of a microliter.
Worked Examples
About the smallest reliable volume off a standard micropipette — the kind of addition you make for a primer or a restriction enzyme.
A typical enzyme aliquot for a small-scale digestion or kinase reaction.
A standard ELISA well or a microplate-format binding assay.
The top of the largest micropipette range, and a common aliquot size for storing a working dilution of a precious reagent.
Common mistakes
µL rendered as uL in exported data
The micro sign does not survive every encoding, so a column headed µL comes back as uL, ul, or mojibake. Repair it by hand and mL sits one keystroke away — a thousandfold error nothing downstream will catch, since mL is a valid volume unit. A plate map carrying it yields reactions that read as merely failed rather than mismeasured. Check the header against a volume you know you pipetted.
Setting a small volume on a big pipette
0.005 mL converts to 5 µL cleanly, and the temptation is to dial it on whatever instrument is already in your hand. A 100–1000 µL pipette will not go there at all; a 20–200 µL one will, and delivers it poorly. The conversion gives you the number, not the tool. Pick the pipette whose range puts 5 µL in its upper half.
Added volume is not final volume
Spiking 10 µL of stock into 1.00 mL of buffer produces 1.01 mL, so the dilution factor is 101 and not 100. One percent survives a single step and does not survive six of them in a serial dilution, where the errors stack in the same direction. Where the factor has to be right, bring the tube to a marked final volume rather than adding to a nominal one.