Convert milligrams to US or Imperial fluid ounces, or fluid ounces to milligrams, using approximate preset or measured density.

Preset densities are approximate examples; temperature and composition affect density. Use measured density when known.

mg to fl oz Formula

Converting milligrams (mass) to fluid ounces (volume) requires density; use the following general relationship with ฯ in g/mL and c as mL per fluid ounce.

fl oz = (mg) / (1000 ฯ c)
  • c (US) = 29.5735295625 mL/fl oz; c (Imperial) = 28.4130625 mL/fl oz.
  • ฯ is the liquid density in g/mL (e.g., water โ‰ˆ 0.9982 g/mL at 20ยฐC).
  • mg to g: g = mg รท 1000; volume (mL) = g รท ฯ.
  • Then convert mL to fluid ounces: fl oz = mL รท c (choose US or Imperial).

mg to fl oz Conversion Notes

Preset densities are approximate examples; composition and temperature matter. Use measured density for a specific sample. Fluid ounces measure volume, not mass; this tool does not determine a medication dose.

Milligrams of Water to US Fluid Ounces (ฯ = 0.9982 g/mL)
Mass (mg) Volume (US fl oz)
1,0000.034
2,0000.068
5,0000.169
10,0000.339
25,0000.847
50,0001.694
75,0002.541
100,0003.388
125,0004.234
150,0005.081
200,0006.775
250,0008.469
300,00010.163
400,00013.550
500,00016.938
750,00025.407
1,000,00033.876
* Assumes water at 20ยฐC (ฯ = 0.9982 g/mL); 1 US fl oz = 29.5735 mL.

How do you convert mg to fluid ounces? Choose US or Imperial fl oz, then compute fl oz = mg รท (1000 ร— ฯ ร— c), where ฯ is density in g/mL and c is 29.5735296 (US) or 28.4130625 (Imperial).

How do you convert fluid ounces to mg? Rearrange: mg = fl oz ร— c ร— ฯ ร— 1000, using c = 29.5735296 (US) or 28.4130625 (Imperial).

Example Problem

Convert 250,000 mg of olive oil to US fluid ounces.

Use the US formula: fl oz = mg รท (1000 ร— ฯ ร— 29.5735), with ฯ (olive oil) โ‰ˆ 0.918 g/mL.

fl oz = 250,000 รท (1000 ร— 0.918 ร— 29.5735295625) โ‰ˆ 9.209 US fl oz