Convert Ounces (oz) to Milligrams (mg)
1 ounce equals 28349.5 milligrams.
Formula:
mg = oz × 28349.5
Ounce to Milligram Converter
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Result
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How to Convert Ounce to Milligram
1 ounce = 28349.5 milligrams
Milligram = Ounce × 28349.5
Example: 1 oz × 28349.5 = 28349.5 mg
Reverse Conversion
To convert milligrams back to ounces:
- Remember, 1 milligram equals 3.5274 × 10-5 ounces.
- To convert 28349.5 mg to oz, multiply
28349.5 x 3.5274 × 10-5, resulting in1 oz.
Common Ounce to Milligram Conversions
| Ounce | Milligram | Actions |
|---|---|---|
| 50 ounces | 1417480 milligrams | |
| 100 ounces | 2834950 milligrams | |
| 500 ounces | 1.41748 × 107 milligrams | |
| 1000 ounces | 2.83495 × 107 milligrams |
Ounces to milligrams Conversion Table
Reference table with common ounces to milligrams conversions. All values calculated with high precision.
Ounces to Milligrams Table
1 to 100000
Milligrams to Ounces Table
10 to 50000
Milligrams to Ounces Table
100000 to 1 × 1010
Definition of Ounce
- Definition
- The ounce (oz) is a unit of mass equal to one sixteenth of a pound in the avoirdupois system. It is commonly used for food portions, postal items, and small packages.
The ounce remains prevalent in countries using imperial or US customary units. - Exact factor
- 1 oz = 28.349523125 g = 0.0625 lb
- Examples
- • 16 oz = 1 lb
• 8 oz ≈ 226.8 g
Definition of Milligram
- Definition
- The milligram (mg) is a metric unit equal to one thousandth of a gram. It is commonly used in medicine, pharmacology, and chemistry to measure very small masses.
This unit allows precise dosage and formulation control, especially where accuracy at micro scales is required. - Exact factor
- 1 mg = 0.001 g = 0.000001 kg
- Examples
- • 500 mg = 0.5 g
• 250 mg = 0.00025 kg
About the Ounce
Facts & Uses
- Avoirdupois ounce equals 1/16 of a pound = exactly 28.349523125 grams (derived from the 1959 Agreement on the pound).
- Standard unit for food portions (deli meats, cheese), postal letter weights (US 1st-class mail), and beverage servings (a 12 oz soda can).
- Common in cooking for both dry and fluid ingredients in the US — though the fluid ounce (volume) and ounce (mass) are unrelated and frequently confused.
- Used in boxing glove weights (8 oz / 10 oz / 12 oz), archery (arrow weight), and jewelry for non-precious metal items.
Curiosities
- The troy ounce (used for gold, silver, platinum) is heavier: 1 troy oz ≈ 31.1035 g, vs. 28.35 g for avoirdupois — a ~10% difference that matters at bullion prices.
- The symbol "oz" derives from the medieval Italian onza, in turn from the Latin uncia meaning "a twelfth part" (originally 1/12 of a Roman pound).
- 16 oz (1 lb) of feathers and 16 oz (1 lb) of gold weigh the same in avoirdupois — but the gold would actually weigh more if measured in troy ounces, since 1 lb troy = 12 troy oz only.
- 1 oz ≈ 28.35 g ≈ 437.5 grains.
Sources
About the Milligram
Facts & Uses
- Equal to 1/1000 of a gram (10⁻⁶ kg). The standard unit for pharmaceutical dosing — paracetamol tablets are 500 mg, ibuprofen 200/400 mg, aspirin 81 mg or 325 mg.
- Universal in medical prescriptions, vitamin and supplement labels, and chemistry lab work where small precise quantities are essential.
- Used for active ingredient concentrations in food, cosmetics, and beverages (caffeine in coffee ≈ 95 mg per cup; sodium in a meal ≈ 600–2000 mg).
- Smaller subdivisions: microgram (1/1000 mg, used for vitamins like B12 and folate); larger: gram, kilogram.
Curiosities
- A typical grain of salt weighs about 0.06 mg; a mosquito weighs around 2.5 mg — milligrams sit at the edge of what we can see and feel.
- Modern analytical balances in laboratories routinely measure to 0.1 mg or 0.01 mg — sensitive enough to detect the weight of a fingerprint smudge.
- Drug overdose thresholds and lethal doses (LD50 values) are almost always reported in mg per kg of body weight — a ratio that scales across species.
- 1 mg ≈ 0.0154 grain ≈ 3.527 × 10⁻⁵ oz.
Sources
Frequently Asked Questions
How many milligrams are in one ounce?
One ounce equals 28349.5 milligrams. To convert, multiply the ounce value by 28349.5. For the reverse, divide the milligram value by 28349.5 (or multiply by 3.5274 × 10-5).
What is 0.04 ounces in milligrams?
0.04 ounces = 1134 milligrams. This is one of the most commonly searched conversions for this pair.
How precise is the ounce-to-milligram conversion?
The factor 28349.5 is accurate to 6 significant figures, derived from international measurement standards. Our calculator uses full precision internally.
Looking for the reverse? Convert Milligram to Ounce
Related Weight (Mass) Converters
Explore other weight (mass) conversion tools:
Need a combined format?
- Kg to Pounds and Ounces — combined lb + oz format
Related in other categories:
- G-force to m/s² — Force = mass × acceleration (F = ma)
Conversion factors verified against NIST (National Institute of Standards and Technology), BIPM (International Bureau of Weights and Measures)
1 lb = 0.45359237 kg by international agreement (1959).
Last reviewed: March 2026
