Enter the mass (mg) and the density into the calculator to determine the volume (mL). The default setting uses the density of water (≈ 1.00 g/mL). This calculator can also convert mL to mg.

mg ↔ mL Calculator
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MG to ML Formula

The following formula is used to convert milligrams to milliliters.

mL = (mg / 1000) / D
  • Where mL is milliliters
  • mg is milligrams
  • D is the density (g/mL or g/cm³)

To calculate milliliters from milligrams, if your density is in g/mL (or g/cm³), convert mg to grams by dividing by 1000, then divide by the density.

mg to mL Reference: Common Substances at 20°C
SubstanceDensity (mg/mL)100 mg500 mg1,000 mg
Water (pure)1,0000.100 mL0.500 mL1.000 mL
Seawater (3.5% salinity)1,0250.098 mL0.488 mL0.976 mL
Whole milk1,0300.097 mL0.485 mL0.971 mL
Hydrogen peroxide (3%)1,0100.099 mL0.495 mL0.990 mL
Glycerin1,2610.079 mL0.397 mL0.793 mL
Corn syrup1,3800.072 mL0.362 mL0.725 mL
Honey1,4000.071 mL0.357 mL0.714 mL
Olive oil9110.110 mL0.549 mL1.098 mL
Canola oil9200.109 mL0.543 mL1.087 mL
Sunflower oil9200.109 mL0.543 mL1.087 mL
Ethanol (pure)7890.127 mL0.634 mL1.267 mL
Acetone7840.128 mL0.638 mL1.276 mL
Gasoline7480.134 mL0.669 mL1.337 mL
Mercury13,5340.0074 mL0.0369 mL0.0739 mL
* Densities at ~20°C. Values rounded to 3 decimal places. Use the calculator above for custom densities.

Medications: Concentration vs. Density

For liquid medications, the label states a concentration (mg/mL), not a physical density. Use concentration directly: mL = prescribed dose (mg) ÷ concentration (mg/mL).

Common Liquid Medication Concentrations (Reference)
MedicationLabelConcentrationExample: 250 mg dose
Acetaminophen (children's)160 mg / 5 mL32 mg/mL7.8 mL
Ibuprofen (children's)100 mg / 5 mL20 mg/mL12.5 mL
Amoxicillin suspension250 mg / 5 mL50 mg/mL5.0 mL
Amoxicillin suspension (high-dose)400 mg / 5 mL80 mg/mL3.1 mL
Azithromycin suspension200 mg / 5 mL40 mg/mL6.3 mL
* Always verify concentration on your specific product label. Consult a pharmacist for dosing guidance.

Mg to mL Definition

Milligrams (mg) measure mass; milliliters (mL) measure volume. These are fundamentally different physical quantities, so a direct conversion requires a bridge: density (g/mL). Density describes how much mass occupies a unit of volume. Water has a density of 1.00 g/mL, so 1,000 mg of water occupies exactly 1 mL. Oils are less dense (~0.91 g/mL), so 1,000 mg of olive oil occupies ~1.1 mL. Honey is denser (~1.40 g/mL), so 1,000 mg of honey fits in just 0.71 mL. The same mass of different substances will always occupy different volumes.

Mg to ML Example

How to convert mg to mL?

  1. First, determine the mass.

    Measure the mass of the substance in mg (or measure in grams and convert: 1 g = 1000 mg).

  2. Next, determine the density.

    Measure the density of the fluid or object (commonly in g/mL or g/cm³).

  3. Finally, calculate the volume.

    Calculate the volume using the formula above.

FAQ

What is mg to mL?

Mg to mL is the conversion of mass (milligrams) to volume (milliliters). Because mass and volume are different physical properties, the conversion requires knowledge of the substance's density. For water at 20°C, 1,000 mg = 1 mL exactly.

Is 1 mg equal to 1 mL?

Only for water. 1 mg of water = 0.001 mL (since water's density is 1,000 mg/mL). For other substances: 1 mg of honey occupies ~0.00071 mL (honey is denser than water), and 1 mg of ethanol occupies ~0.00127 mL (ethanol is less dense than water).

What is 500 mg in mL?

It depends on the substance. For water: 500 mg = 0.5 mL. For olive oil (density 911 mg/mL): 500 mg = 0.549 mL. For glycerin (density 1,261 mg/mL): 500 mg = 0.397 mL. Use the formula: mL = mg ÷ density (mg/mL).

How do I convert mg to mL for a liquid medication?

For medications, use the concentration printed on the label (e.g., '250 mg/5 mL' = 50 mg/mL), not physical density. Divide the prescribed dose in mg by the concentration: mL = dose (mg) ÷ concentration (mg/mL). Example: a 125 mg dose of amoxicillin 250 mg/5 mL suspension = 125 ÷ 50 = 2.5 mL. Always confirm with a pharmacist.