Convert ounces to milligrams

1 oz=28,349.52mg

Use the converter below to change any ounces value into milligrams instantly — with formula, conversion table, and real-world examples.

You have

Equals

28,349.52

Conversion formula

Forward

milligrams = ounces × 28,349.52

Reverse

ounces = milligrams × 3.5274e-5

Example: 10 oz × 28,349.52 = 283,495.23 mg.

About both units

From

Ounce

The ounce equals 28.35 grams and is 1/16 of a pound. It is common in American and British cooking for small ingredient weights. The fluid ounce (29.57 ml in the US, 28.41 ml in the UK) is a volume unit and is completely different from the mass ounce.

Real-world: A US tin of tuna is 5 oz (142 g). A Starbucks grande coffee is 16 fl oz (473 ml). Gold is traded in troy ounces (31.10 g).

Read full ounce reference →

Milligram

The milligram equals one thousandth of a gram. It is the dosing unit for most oral medications. A standard paracetamol tablet contains 500 mg. The daily recommended intake of iron for adult men is 8 mg, for women 18 mg. Micrograms (µg) are used for even smaller quantities like vitamin D.

Real-world: A paracetamol tablet is 500 mg. Daily iron intake: 8 mg (men) / 18 mg (women). Aspirin for heart protection: 75–100 mg daily.

Read full milligram reference →

Ounce to Milligram conversion table

Common ounces to milligrams values for quick reference.

Ounce (oz)	Milligram (mg)
1 oz	28,349.52 mg
5 oz	141,747.62 mg
10 oz	283,495.23 mg
25 oz	708,738.08 mg
50 oz	1,417,476.16 mg
100 oz	2,834,952.31 mg
250 oz	7,087,380.78 mg
500 oz	14,174,761.56 mg
1,000 oz	28,349,523.13 mg
5,000 oz	141,747,615.63 mg

Tips & common mistakes

Quick tips

1 oz = 28.35 g exactly (avoirdupois); 1 troy oz = 31.10 g.
16 oz = 1 lb in the avoirdupois system used for food.
When converting a US recipe, 1 oz ≈ 2 tablespoons of a liquid ingredient.

Avoid these

Confusing mass ounces (28.35 g) with fluid ounces (volume).
Using avoirdupois ounces (28.35 g) for precious-metal pricing — gold is in troy ounces (31.10 g).
Multiplying lb × 16 and calling the result oz — correct only for weight, not volume.

Frequently asked questions

How many milligrams in a ounce?

One ounce equals 28,349.52 milligrams.

How do I convert ounces to milligrams?

Multiply the ounce value by 28,349.52 to get the equivalent in milligrams.

What is 100 ounces in milligrams?

100 ounces equals 2,834,952.31 milligrams.

Is a ounce bigger than a milligram?

Yes. 1 ounce equals 28,349.52 milligrams, so one ounce is larger.

How to convert ounces to milligrams without a calculator?

Multiply by 28,349.52 for a quick estimate; use a calculator for precise results.

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