Drams to Grams Converter

How it is calculated

The tool treats the dram as the avoirdupois dram and multiplies by fixed factors: grams = drams × 1.7718451953 and ounces = drams × 0.0625, because 16 drams make one avoirdupois ounce (28.3495 g). Results are shown to four decimals. Any number is accepted, including decimals, but the tool does not warn about negative values. It does not convert the apothecaries' dram (also called the fluid dram when used for liquids), which is a different unit of about 3.888 g, so a prescription written in apothecary drams will come out too low here. The conversion is exact for mass; it is not a volume conversion.

Common mistakes

• Applying the avoirdupois dram to an apothecary prescription: the apothecary dram is about 3.888 g, more than twice as heavy, which in medicine is a serious dosing error.
• Confusing the mass dram with the fluid dram, a volume unit used for liquids, which cannot be converted to grams without the liquid's density.
• Treating a dram as 1/8 of an ounce, which is the apothecary relation, while the avoirdupois dram is 1/16 of an ounce.
• Rounding the factor to 1.77 g on a large quantity; at 1,000 drams that drifts by almost 2 g.
• Reading the ounce result as fluid ounces; it is the avoirdupois ounce of weight.