How Many Milligrams in an Ounce?

Multiply the ounces by 28,349.5. The numbers grow fast, so it often helps to go through grams: multiply by 28.3495 for grams, then by 1,000 for milligrams.

0.25 oz is 7.09 g, or 7,087 mg. 2 oz is 56,699 mg, a five-digit figure that reads more easily as 56.7 g.

These are ounces of weight. If a bottle is marked in fluid ounces, it states a volume, and its weight in milligrams depends on what is inside. Check the label for "fl oz" before you convert.

Convert the ounces to milligrams, then divide by the portion size. A 0.5 oz tin of saffron holds 14,175 mg, so at 150 mg per pot of rice it is enough for about 94 pots.

A 3 oz bag of loose tea at 2,500 mg per pot makes 34 pots. For amounts like these, a scale that reads to the milligram, or at least to a hundredth of a gram, is the right tool.

Divide the milligrams by 28,349.5. The answers are small: 500 mg is 0.01764 oz, and even 10,000 mg is only 0.3527 oz. At 100 mg, the result is 0.003527 oz, far below what a kitchen scale set to ounces can show.

Because of that, an ounce figure for a milligram amount is rarely useful on its own. If you need to weigh it, convert to grams instead, where 10,000 mg becomes a simple 10 g.