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mg to mL Calculator
Milligrams measure weight and milliliters measure volume, so converting between them needs one more number: how much of the substance is in each milliliter. Enter the strength printed on a label, such as 160 mg per 5 mL, or a pure liquid’s density, and convert either way.
- Milliliters
- 7.5 mL
- Milligrams
- 240 mg
- Concentration
- 32 mg/mL
- In US teaspoons
- 1.52 tsp
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Formula
How to use it
- Choose mg to mL or mL to mg.
- Choose whether to use a label strength or a density.
- Enter the strength exactly as printed — for “250 mg/5 mL”, 250 and 5 — or the density.
- Enter the amount and read the result.
Worked examples
240 mg from a liquid labeled 160 mg per 5 mL (32 mg in every mL)
- Result
- 7.5 mL
- Milliliters
- 7.5 mL
- Concentration
- 32 mg/mL
- In US teaspoons
- 1.52 tsp
2.5 mL of a liquid labeled 250 mg per 5 mL
- Result
- 125 mg
- Milligrams
- 125 mg
- Concentration
- 50 mg/mL
500 mg of water, at 1 g (1,000 mg) per mL
- Result
- 0.5 mL
- Milliliters
- 0.5 mL
- Concentration
- 1,000 mg/mL
One US teaspoon (4.93 mL) of olive oil at 0.91 g/mL
- Result
- 4485.3 mg
- Milliliters
- 4.93 mL
- Milligrams
- 4,485.3 mg
Medicines: follow the label
This converter does arithmetic only and does not know the right dose for anyone. The same medicine can be sold in more than one strength, so always read the strength on the bottle you have, follow the dosing directions on the label or from your doctor or pharmacist, and ask a pharmacist if anything is unclear.
Measure liquid medicine with the oral syringe or dosing cup that comes with it. Kitchen spoons vary widely in size, and mixing up milliliters and teaspoons is a common cause of dosing mistakes.
Why “1 mL = 1,000 mg” only works for water
A milliliter of water weighs very close to 1 g (1,000 mg) at room temperature, so for water and very dilute solutions mg and mL convert at 1,000 to 1. Other liquids differ: olive oil is about 0.91 g/mL, so 1 mL weighs about 910 mg, and honey is about 1.4 g/mL. In a solution, the milligrams on a label refer to the dissolved ingredient, not the whole liquid, which is why the label strength is what you need.
Questions people ask
How do I convert mg to mL?
Divide the milligrams by the concentration in mg per mL. For a label reading 160 mg/5 mL the concentration is 32 mg/mL, so 240 mg is 240 ÷ 32 = 7.5 mL.
How many mL is 5 mg?
It depends on the concentration: 5 mL at 1 mg/mL, 0.5 mL at 10 mg/mL. For pure water, 5 mg is only 0.005 mL.
How many mg are in 1 mL?
1,000 mg if it is water. For a solution, it is the label strength per mL: a liquid labeled 250 mg/5 mL has 50 mg in each mL.