Dram to Grams Converter (dr ⇄ g)

Not for medical dosing

Convert between drams and grams with support for both avoirdupois drams and apothecaries drams. The tool computes all three values at once and lets you decide which historical system fits your use case.

Key factors: 1 avoirdupois dram ≈ 1.771845 g, 1 apothecaries dram ≈ 3.8879346 g.

Main converter – drams ⇄ grams

Handles both dram systems

Enter the numeric value you want to convert.

Presets:

Synchronized grams & drams table

All values update with the main converter

Whenever you use the main converter, this panel shows the equivalent values in grams, avoirdupois drams and apothecaries drams.

1 dr (avdp) ≈ 1.771845 g

1 dr (apoth) ≈ 3.8879346 g

Quick reference: drams to grams

The table below compares avoirdupois and apothecaries drams for common small integer values.

Drams (dr) Grams (avdp) Grams (apothecaries)
1 1.771845 3.887935
2 3.543690 7.775869
4 7.087381 15.551738
8 14.174761 31.103477
16 28.349922 62.206954

Understanding the dram units

The term dram (or drachm) appears in more than one historical system of units. For mass, the two most commonly referenced are:

  • Avoirdupois dram – part of the everyday imperial system used for goods, where 16 ounces make one pound.
  • Apothecaries dram – part of the historical pharmacy system, where 12 ounces make one pound.

Exact relationships used in this calculator

From drams to grams

Grams from avoirdupois drams: \(\text{g} = \text{dr}_{\text{av}} \times 1.7718451953\)

Grams from apothecaries drams: \(\text{g} = \text{dr}_{\text{ap}} \times 3.8879346\)

From grams to drams

Avoirdupois drams: \(\text{dr}_{\text{av}} = \dfrac{\text{g}}{1.7718451953}\)

Apothecaries drams: \(\text{dr}_{\text{ap}} = \dfrac{\text{g}}{3.8879346}\)

Worked example: 5 drams (avdp) to grams

  1. Select From: drams (avoirdupois) and To: grams.
  2. Enter value 5 in the main field.
  3. The calculator multiplies 5 × 1.771845 ≈ 8.859225 g.
  4. The synchronized view also shows the equivalent apothecaries drams for the same gram value.

Worked example: 10 grams to apothecaries drams

  1. Select From: grams and To: drams (apothecaries).
  2. Enter value 10.
  3. The calculator divides 10 by 3.8879346, giving approximately 2.571 dr (apothecaries).
  4. The synchronized view shows the equivalent value in avoirdupois drams as well.

FAQ: dram to grams conversions

Which dram should I use for non-medical technical work?

For most non-medical, non-pharmacy applications, if a “dram” appears without further context, it is usually safer to assume the avoirdupois dram. If you are dealing with historical pharmaceutical recipes or texts, the apothecaries dram is more likely.

Why is there a warning about medical use?

Modern pharmacology uses the metric system (mg, g, mL) with strictly defined dosing protocols. Historical dram-based prescriptions are not meant to be recreated directly. This converter is purely educational and technical, not a substitute for medical judgment.

Why do different websites show slightly different decimal values?

The underlying conversion factors are exact or well-established, but different tools may round at different stages or show fewer digits. This calculator keeps sufficient precision internally and rounds the display to a practical number of decimals for readability.