Milligrams to Millilitres Calculator
Volume of a liquid that holds a given mass, from the concentration on the label — because milligrams and millilitres only relate through that number.
With amount needed 250 mg, concentration on the label 125 mg/ml, milligrams to millilitres comes to 2.000 ml — volume. It is reached in 4 steps, the last of which is mass / concentration, and each one is printed on the page with its numbers filled in. The formula is the one published by NIST Handbook 44, not an approximation fitted to it.
Formula and sources checked · How we check
Amount needed 250 mg, Concentration on the label 125 mg/ml
2.000 ml
Volume for the example below. Editing a field recomputes the calculator below; this figure holds the answer the page was loaded with.
It is written into the HTML rather than drawn by a script, so a search engine reading this page without running JavaScript still finds an answer.
- Volume
mass / concentration2 ml- In US teaspoons
volume / 4.928921593750.406 tsp- Amount in one millilitre
concentration125 mg- That volume back to milligrams
volume * concentration250 mg
Worked example
To get 250 mg from a liquid at 125 mg/ml you need 2 ml. Multiplying back gives 250 mg, which is the check worth doing: if the two do not agree, the concentration was entered wrong.
How to work it out yourself
- 1.Read the concentration from the label. It is written as mg/ml, or as a pair like "125 mg / 5 mL".
- 2.If it is a pair, divide the milligrams by the millilitres first — 125 in 5 mL is 25 mg/ml.
- 3.Divide the amount you need by the concentration. The answer is in millilitres.
- 4.Multiply the answer back by the concentration and check it returns the amount you started with.
The formula
- Volume
mass / concentration - In US teaspoons
volume / 4.92892159375 - Amount in one millilitre
concentration - That volume back to milligrams
volume * concentration
Source: NIST Handbook 44 — mass and volume, BIPM SI Brochure — the litre and the kilogram
Questions people actually ask
- Why can I not convert mg to ml directly?
- One is a mass and the other a volume, and nothing connects them without knowing how much of the substance sits in each millilitre. That is what the concentration is, and it differs between products with the same name.
- Is 1 ml the same as 1 g?
- Only for pure water at about 4°C, and only approximately. For anything dissolved in water, syrup or oil it is wrong, sometimes badly. Use the concentration printed on the label.
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