| Milliliters per minute (mL/min) | Cubic meters per minute (m³/min) |
|---|---|
| 1 Milliliter per minute | 0.000001 m³/min |
| 2 Milliliters per minute | 0.000002 m³/min |
| 3 Milliliters per minute | 0.000003 m³/min |
| 4 Milliliters per minute | 0.000004 m³/min |
| 5 Milliliters per minute | 0.000005 m³/min |
| 10 Milliliters per minute | 0.00001 m³/min |
| 20 Milliliters per minute | 0.00002 m³/min |
| 25 Milliliters per minute | 0.000025 m³/min |
| 50 Milliliters per minute | 0.00005 m³/min |
| 100 Milliliters per minute | 0.0001 m³/min |
| Reference | Milliliters per minute (mL/min) | Cubic meters per minute (m³/min) |
|---|---|---|
| A domestic shower | 9000 mL/min | 0.009 m³/min |
| A kitchen tap | 10000 mL/min | 0.01 m³/min |
| A garden hose | 15000 mL/min | 0.015 m³/min |
| The Amazon river | 1.254 × 1013 mL/min | 12540000 m³/min |
The millilitre per minute is a unit of volumetric flow rate equal to one millilitre passing a point every minute. Its symbol is mL/min. It is the working unit of clinical medicine and of analytical chemistry, two fields in which the quantity delivered matters far more than the speed of delivery.
Intravenous infusion is the clearest case. A drip is set in millilitres per hour for slow fluids and in millilitres per minute for fast ones, and an infusion pump is programmed with a rate and a volume. A litre of saline given over four hours runs at about four millilitres per minute; the same litre given rapidly in an emergency may run at a hundred.
Liquid chromatography works in the same range. A conventional analytical column is run at one millilitre per minute, a figure so standard that it appears as a default in almost every published method. Narrower columns run proportionally slower, and the flow must be held steady to within a fraction of a per cent, because the time at which a compound emerges depends on it.
Anaesthetic and oxygen delivery use the unit too, though there the fluid is a gas. Oxygen therapy is prescribed in litres per minute, and the small adjustments within that are made in hundreds of millilitres per minute. In each case the rate is a prescription, and the equipment exists to hold it constant.
Sixty millilitres per minute is one millilitre per second, so the conversion between the two is the same factor as between minutes and seconds. That relationship makes it easy to move between the fast and slow ends of the same equipment: a pump specified in millilitres per minute can be reasoned about in millilitres per second by dividing by sixty.
For everyday scale, a millilitre per minute would fill a teaspoon in five minutes and a cup in four hours. It is a rate slow enough that watching it is uninformative, which is why the instruments that use it display a totalised volume as well as a rate.
One millilitre per minute equals about 0.01667 millilitres per second, 60 millilitres per hour, or 0.001 litres per minute.
The cubic metre per minute is a unit of volumetric flow rate equal to one cubic metre passing a point every minute. Its symbol is m³/min. It occupies the middle ground of industrial air handling: large enough for a factory's compressed-air main, small enough that the number stays in two or three digits.
Compressors are its most familiar users. A workshop screw compressor delivers 1 to 10 cubic metres per minute of free air, a large industrial machine 50 or more, and the rating is always given as free air delivery — the volume measured at atmospheric conditions rather than at the compressed pressure, because that is what the tools downstream actually consume.
Sizing a compressed-air system is an exercise in adding these numbers. Each tool has a consumption figure: an impact wrench 0.6 cubic metres per minute, a spray gun 0.3, a sandblasting nozzle several. Total them, apply a duty factor because they do not all run at once, add a margin for leaks, and the result is the compressor the workshop needs.
Mine and tunnel ventilation is quoted the same way. Regulations set a minimum air quantity per person and per unit of diesel power underground, and a working face may require 20 to 50 cubic metres per minute. The main fan at the surface handles the sum of every face, which is why the unit spans four orders of magnitude within a single industry.
Blowers, dust extraction and pneumatic conveying complete the picture. A woodworking dust extractor is rated at 20 to 60 cubic metres per minute, a bag filter for a cement plant at thousands, and a pneumatic conveyor is designed around the air velocity in the pipe, which the flow and the pipe cross-section together determine.
The conversion to its neighbours is easy in both directions. Sixty cubic metres per minute is one cubic metre per second, and one cubic metre per minute is a thousand litres per minute. That last relation is why the same fan can appear in a European catalogue as 1,200 litres per second and in another as 72 cubic metres per minute.
One cubic metre per minute equals about 0.01667 cubic metres per second, 1,000 litres per minute, or about 35.31 cubic feet per minute.