Here's how to convert milligrams (mg) to ounces:

Conversion Factors:

* 1 ounce (oz) = 28,349.5 milligrams (mg)

Calculation:

1. Divide the milligrams by the conversion factor: 18,000 mg / 28,349.5 mg/oz ≈ 0.635 oz

Answer: There are approximately 0.635 ounces in 18,000 milligrams.