How many milligrams are in one dram?

One avoirdupois dram contains approximately 1,771.8 milligrams. This comes from 1 dram being about 1.7718 grams and 1 gram containing 1,000 milligrams.

Why did pharmacy abandon the dram for milligrams?

Three reasons: precision (milligrams are finer), universality (milligrams are the same worldwide), and safety (no confusion between avoirdupois and apothecary drams, which differed by a factor of 2.2).

What was a typical dram-based prescription?

19th-century prescriptions commonly used fractions of a dram: 'one-half dram' (886 mg), 'one-quarter dram' (443 mg), or 'two drams' (3,544 mg). These quantities were compounded by hand by the dispensing pharmacist.

Drams to Milligrams (dr to mg) Converter

1 dr = 1,771.8452 mg

1 Dram equals 1,771.8452 Milligrams (1 dr = 1,771.8452 mg). Convert Drams to Milligrams with formula, table, and examples.

One dram equals approximately 1,771.8 milligrams. The milligram, the workhorse of pharmaceutical measurement, provides a far more practical unit than the dram for modern applications. At roughly 1,772 milligrams per dram, converting between these units is essential when interpreting historical pharmaceutical records that used drams for dosing instructions now expressed exclusively in milligrams.

How to Convert Drams to Milligrams

mg = dr × 1,771.8451953125

Multiply the value in Drams by 1,771.8451953125

Take your value in Drams
Multiply by 1,771.8451953125
Read the result in Milligrams

Common Drams to Milligrams Conversions

Drams (dr)	Milligrams (mg)	Status
0.01 dr	17.718 mg
0.05 dr	88.592 mg
0.1 dr	177.185 mg
0.25 dr	442.961 mg
0.5 dr	885.923 mg
1 dr	1,771.845 mg
2 dr	3,543.69 mg
5 dr	8,859.226 mg
10 dr	17,718.452 mg
16 dr	28,349.523 mg
25 dr	44,296.13 mg
50 dr	88,592.26 mg
100 dr	177,184.52 mg
256 dr	453,592.37 mg
500 dr	885,922.598 mg

Good to Know About Drams to Milligrams Conversion

The dram-to-milligram transition in pharmacy represents one of the most important measurement changes in medical history. When the US Pharmacopeia officially dropped drams and scruples in favor of metric units in the mid-20th century, it ended centuries of measurement ambiguity that had caused preventable patient harm. The switch to milligrams was not a matter of convenience but of survival.

Drams to Milligrams: What You Need to Know

A Victorian prescription for 'half a dram of laudanum' translates to about 886 milligrams of the opium preparation. Modern pharmacists who encounter such historical prescriptions in archived medical records need this conversion to understand historical dosing practices. Today, opioid doses are specified in single-digit milligrams with extreme precision - a dramatic change from the dram-scale dosing of the 19th century.

What is a Dram? dr

A dram (avoirdupois) is a unit of mass equal to 1/16 of an ounce or 1/256 of a pound (1.7718451953125 grams). Historically used in pharmacy and old cooking recipes.

Imperial historical pharmacy old recipes whisky measurement

Learn more about Dram →

What is a Milligram? mg

A metric unit of mass equal to one thousandth of a gram, or one millionth of a kilogram. Commonly used in medicine and pharmacology.

Metric medicine pharmacology nutrition

Learn more about Milligram →

Going the other way? Use our Milligrams to Drams converter.

Drams to Milligrams FAQ

One avoirdupois dram contains approximately 1,771.8 milligrams. This comes from 1 dram being about 1.7718 grams and 1 gram containing 1,000 milligrams.
Three reasons: precision (milligrams are finer), universality (milligrams are the same worldwide), and safety (no confusion between avoirdupois and apothecary drams, which differed by a factor of 2.2).
19th-century prescriptions commonly used fractions of a dram: 'one-half dram' (886 mg), 'one-quarter dram' (443 mg), or 'two drams' (3,544 mg). These quantities were compounded by hand by the dispensing pharmacist.

Non-Frequently Asked Questions About Drams to Milligrams

Questions nobody should ask - but someone did.

One dram (1,772 milligrams) is a substantial dose by modern standards. For context, a maximum daily dose of ibuprofen is 3,200 milligrams (about 1.8 drams), and a typical aspirin tablet is 325 milligrams (about 0.18 drams). The Victorians were often taking potent, unregulated substances at what we would now consider alarming quantities.
Apothecary shops had sets of nested brass weights calibrated in drams, scruples, and grains. A dram weight sat on one side of a balance; the drug was spooned onto the other side until the beam leveled. It was slow, manual, and accurate to perhaps 50 to 100 milligrams - which for most medicines of the era was sufficient.
No modern regulatory agency would accept dram-based dosing. The FDA, EMA, and every national drug authority require dosing in metric units (mg, mcg, or mL). A drug application specifying doses in drams would be returned for revision before anyone even read the efficacy data.