How many avoirdupois drams are in one scruple?

One scruple equals approximately 0.731 avoirdupois drams. Note that this crosses from the apothecary to the avoirdupois system. Within the apothecary system, one scruple is exactly one-third of an apothecary dram.

What is the difference between an apothecary dram and an avoirdupois dram?

An apothecary dram weighs about 3.888 grams (60 grains) while an avoirdupois dram weighs about 1.772 grams (27.34 grains). The apothecary dram is more than twice as heavy, which is why the scruple converts so differently depending on which dram system you target.

How many scruples are in one apothecary dram?

Exactly 3 scruples make one apothecary dram. This is a clean definitional ratio: 3 scruples of 20 grains each equal one dram of 60 grains.

Scruples to Drams (s ap to dr) Converter

1 s ap = 0.7314 dr

1 Scruple equals 0.7314 Drams (1 s ap = 0.7314 dr). Convert Scruples to Drams with formula, table, and examples.

One scruple equals approximately 0.731 avoirdupois drams. In the apothecary system itself, exactly 3 scruples make one apothecary dram, giving a clean 1:3 ratio within that tradition. However, converting to the avoirdupois dram produces the less tidy 0.731 factor because the two drams belong to different weight systems and have different masses.

How to Convert Scruples to Drams

dr = s ap × 0.7314285714

Multiply the value in Scruples by 0.7314285714

Take your value in Scruples
Multiply by 0.7314285714
Read the result in Drams

Common Scruples to Drams Conversions

Scruples (s ap)	Drams (dr)	Status
0.5 s ap	0.365714 dr
1 s ap	0.731429 dr
3 s ap	2.194286 dr
5 s ap	3.657143 dr
10 s ap	7.314286 dr
20 s ap	14.628571 dr
24 s ap	17.554286 dr
50 s ap	36.571429 dr
100 s ap	73.142857 dr
200 s ap	146.285714 dr
288 s ap	210.651429 dr
500 s ap	365.714286 dr
1,000 s ap	731.428571 dr
5,000 s ap	3,657.142857 dr

Good to Know About Scruples to Drams Conversion

The two-dram problem encapsulates everything confusing about pre-metric English measurement. The same word 'dram' referring to two units of wildly different weight in related but distinct systems created genuine risks in a profession where precision was life-critical. The metric system's unambiguous milligram eliminated this danger entirely, which is why pharmacists were among the first professionals to abandon imperial weights despite the transition costs.

Scruples to Drams: What You Need to Know

The scruple-to-dram relationship is fundamental within the apothecary system, where pharmacists subdivided drams into three scruples for precise dosing. The apothecary dram (3.888 grams) is more than twice the weight of the avoirdupois dram (1.772 grams), which is why the cross-system conversion produces an apparently counterintuitive result where one scruple is less than one avoirdupois dram despite being exactly one-third of an apothecary dram.

What is a Scruple? s ap

An apothecary scruple equals 20 grains or 1/3 of a dram apothecary (1.2959782 grams). A historical pharmaceutical unit largely replaced by metric measurements.

Apothecaries historical pharmacy historical medicine

Learn more about Scruple →

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 →

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

Scruples to Drams FAQ

One scruple equals approximately 0.731 avoirdupois drams. Note that this crosses from the apothecary to the avoirdupois system. Within the apothecary system, one scruple is exactly one-third of an apothecary dram.
An apothecary dram weighs about 3.888 grams (60 grains) while an avoirdupois dram weighs about 1.772 grams (27.34 grains). The apothecary dram is more than twice as heavy, which is why the scruple converts so differently depending on which dram system you target.
Exactly 3 scruples make one apothecary dram. This is a clean definitional ratio: 3 scruples of 20 grains each equal one dram of 60 grains.

Non-Frequently Asked Questions About Scruples to Drams

Questions nobody should ask - but someone did.

Because the apothecary and avoirdupois systems evolved independently for different trades and nobody coordinated the naming. The apothecary dram (60 grains) served pharmacy; the avoirdupois dram (27.34 grains) served general commerce. That both are called 'dram' despite being more than two-to-one different in weight is one of the English measurement system's most egregious naming failures.
Three scruples of conscience would make one full apothecary dram of doubt, which at 3.888 grams is a substantial quantity of moral hesitation. In avoirdupois terms, the same three scruples would produce 2.19 drams of doubt, which is confusing enough to add even more doubt about which measurement system to use for your ethical uncertainties.
This was a genuine and dangerous risk. An apothecary dram is 2.19 times heavier than an avoirdupois dram, so confusing the two could result in a dose more than double what was intended. Historical pharmacy manuals repeatedly warn students about this distinction, and the potential for dram confusion was one of the strongest arguments for adopting the unambiguous metric system.