How this instrument works
A litre is defined as one cubic decimetre. A decimetre is ten centimetres, and ten cubed is 1000, so exactly 1000 cubic centimetres fill one litre with nothing left over — the factor falls straight out of decimal geometry rather than out of any physical standard. Written cc, a cubic centimetre is cm³ typed without a superscript, and it names precisely the same volume as a millilitre; the two labels have been strictly interchangeable since the CGPM restored the litre to the cubic decimetre definition in 1964.
That equivalence matters most where a large stock volume needs to be dispensed in small measured doses. Intravenous fluids are stocked in litre and half-litre bags — a 1 L bag of normal saline, a 3 L bag of peritoneal dialysate — but clinicians chart and infusion pumps display the volume actually delivered in millilitres or, informally on many drug charts and syringe barrels, in cc: 'give 500cc bolus' or 'infuse at 125 cc/hr' are phrases nurses hear on rounds, even though the bag itself is labelled in litres or millilitres. Multiplying by 1000 is the whole of the arithmetic connecting the two labels on the same fluid.
Outside medicine, the split runs along similar lines: containers big enough to carry — bottled water, engine coolant, home-brewing wort, paint — are quoted in litres, while small precise volumes needing fine graduation — laboratory pipettes and graduated cylinders, engine displacement in cc, syringe barrels — use cubic centimetres or millilitres. A single fluid can cross both worlds on its way from bulk stock to a measured dose.
- Enter the volume in the Litres (l) field; it opens at 2, a common large IV bag or bottle size.
- Read the Cubic centimetres (cc) line beneath it — it recalculates on every keystroke to one decimal place.
- Have millilitres already? Skip this step entirely: 1 mL and 1 cc are the same volume, so no conversion is needed there.
- Going from cc back to litres, divide by 1000 — 750 cc becomes 0.75 l.
- For dosing or infusion-rate work, double-check the resulting cc figure against your chart or pump display before administering anything; this sheet performs arithmetic only.
Worked example — a 2 litre IV fluid bag
A hospital pharmacy stocks large-volume parenteral bags in round litre sizes, and a 2 L bag of replacement fluid is a standard size on many wards. Enter 2 into Litres (l) and the Cubic centimetres (cc) line returns 2000.0 — the figure a nurse would see on an infusion pump's 'volume to be infused' display, since pumps are programmed in mL/cc, not litres.
Scale that down to a bedside order: if that same 2 L bag is to run over 16 hours, the pump rate works out to 2000 cc ÷ 16 h = 125 cc/hr, a rate written on drug charts exactly that way. The litre figure on the bag label and the cc figure on the pump screen describe the identical fluid; only the unit chosen for the audience differs.
Questions
Is a cubic centimetre exactly the same volume as a millilitre?
Yes, and it has been without exception since 1964. Both equal one thousandth of a litre, itself one cubic decimetre, so 1 cc = 1 mL = 0.001 l with nothing rounded anywhere. Between 1901 and 1964 the litre was instead pegged to the volume of one kilogram of water, which made a millilitre about 28 parts per million larger than a cc — a gap so small that only chemistry demanding six significant figures ever noticed it, and one that no longer exists.
Why do hospital charts say cc instead of mL?
Mostly habit carried over from older medical training, though patient-safety bodies including the Institute for Safe Medication Practices and the Joint Commission now discourage handwritten 'cc' because it is easily misread as 'u' for units or as '00', both of which have caused real dosing errors. NIST and most style guides for clinical writing recommend mL in print for the same reason; this sheet supports both because both appear in real practice, but mL is the safer choice on a handwritten order.
Why is the factor exactly 1000 rather than an approximation?
Because it is pure geometry, not physical measurement. One litre is defined as one cubic decimetre, one decimetre is ten centimetres, and ten cubed is 1000. Multiplying litres by 1000 to reach cubic centimetres is therefore a shift of three decimal places every time, at any level of precision your equipment can support.
How does an infusion pump rate in cc/hr relate to a litre bag size?
Divide the bag's total volume in cc by the number of hours the infusion should run. A 1 L (1000 cc) bag ordered over 8 hours runs at 125 cc/hr; the same bag over 4 hours runs at 250 cc/hr. This sheet only performs the litre-to-cc step of that calculation — rate, timing and clinical appropriateness are set by the prescribing order, not by unit conversion.
What is the most common mistake converting between litres and cc?
Shifting two decimal places instead of three, because 'centi-' suggests hundredths on its own. The cubic centimetre is actually one thousandth of a litre, since the prefix gets cubed along with the length it modifies: a centimetre is 0.01 m, but a cubic centimetre is 0.01³ = 0.000001 m³, which is 0.001 l, not 0.01 l. Watch the next unit up as well — 1 m³ is 1000 l, not 100.
Is the litre itself an SI unit?
Not strictly. The coherent SI unit of volume is the cubic metre; the litre is one of a short list of non-SI units accepted for everyday and laboratory use alongside SI because it suits bottle sizes and glassware so well. That accepted status is why a single 2 L volume can equally correctly be written 2 l, 2000 mL, 2000 cc, 2000 cm³ or 0.002 m³, and why chemists reporting results to high precision are advised to work in cubic decimetres instead.