Divide the number of ounces by 0.0625 to convert to drams. For example, if you have 10 ounces, divide 10 by 0.0625 to get 160 dr.
Multiply the number of ounces by 16 to convert to drams. In this example, check your answer by multiplying 10 by 16 to get 160 dr.
Verify your answer using an online ounces-to-drams calculator. Select ounce (avoirdupois) in the "From" drop-down menu and dram (avoirdupois) from the "To" drop-down menu. Then enter the number of ounces and click "Convert."