Mass and Weight · Unit Converter

Convert Dram (apothecary/troy) to Pennyweight

Convert drams (apothecary/troy) to pennyweights instantly. 1 dram (apothecary/troy) = 2.5000000643 pennyweight — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Pennyweight to Dram (apothecary/troy) converter for the reverse conversion.

Written by Sunith Babu L, Ph.D., Lead Engineer Reviewed by Dr. Ashok Kumar K, Ph.D.
Mass and Weight category 2 min read Published Last reviewed Updated

Units explained

Troy & Apothecary

Dram (apothecary/troy)

What is a dram (apothecary/troy)?

The apothecary (troy) dram equals one-eighth of a troy ounce, about 3.888 grams.

Origin of the dram (apothecary/troy)

From the apothecaries' system rooted in the Greek 'drachma'.

Where it is used

Historical pharmacy and medicine compounding.

When and where it was developed

Part of the apothecaries' system of weights used through the 19th century.

Troy & Apothecary

Pennyweight

What is a pennyweight?

The pennyweight (dwt) equals one-twentieth of a troy ounce, 24 grains (about 1.555 g).

Origin of the pennyweight

From the mass of a medieval English silver penny; symbol dwt from 'denarius weight'.

Where it is used

Jewelry making and precious-metal scrap valuation in the US.

When and where it was developed

Derived from the medieval English coinage system.

Dram (apothecary/troy) to Pennyweight conversion formula

The relationship between drams (apothecary/troy) and pennyweights:

1 dr ap = 2.5000000643 dwt
1 dwt = 0.3999999897 dr ap

To convert drams (apothecary/troy) to pennyweights, multiply the value in drams (apothecary/troy) by 2.5000000643. To reverse, multiply pennyweights by 0.3999999897.

How to use this converter

Type a value into the calculator. The result in pennyweights updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Pennyweight to Dram (apothecary/troy) converter for the reverse direction.

Step-by-step: convert drams (apothecary/troy) to pennyweights

  1. Write down the value in drams (apothecary/troy) (dr ap).
  2. Multiply that value by the factor 2.5000000643.
  3. The product is the equivalent value in pennyweights (dwt).
  4. To reverse, multiply the pennyweight value by 0.3999999897.

Worked examples

Example 1 — Convert 1 dr ap to dwt:
1 × 2.5000000643 = 2.5000000643 dwt

Example 2 — Convert 100 dr ap to dwt:
100 × 2.5000000643 = 250.0000064301 dwt

Real-world example — Ruler-scale measurements

A 30-dram (apothecary/troy) school ruler converts cleanly to pennyweights — useful when buying a desk accessory from a retailer whose product specs use a different unit.

30 dr ap × 2.5000000643 = 75.000001929 dwt

Real-world example — Hardware-scale dimensions

A 10-dram (apothecary/troy) fastener or component is about as long as a thumbnail. Mechanics and DIY enthusiasts convert between drams (apothecary/troy) and pennyweights daily when mixing metric and imperial tools.

10 dr ap × 2.5000000643 = 25.000000643 dwt

Real-world example — Postcard and small-object dimensions

A postcard is about 5 drams (apothecary/troy) wide. Converting to pennyweights is essential for international postal addressing forms that ask for dimensions in different units across countries.

5 dr ap × 2.5000000643 = 12.5000003215 dwt

Dram (apothecary/troy) to Pennyweight conversion table

Standard reference values for converting drams (apothecary/troy) to pennyweights:

Dram (apothecary/troy) [dr ap]Pennyweight [dwt]
0.010.0250000006
0.10.2500000064
12.5000000643
25.0000001286
37.5000001929
410.0000002572
512.5000003215
1025.000000643
2050.000001286
3075.000001929
40100.0000025721
50125.0000032151
100250.0000064301
5001250.0000321507
10002500.0000643015

Frequently asked questions

How many pennyweights is 1 dram (apothecary/troy)?
1 dram (apothecary/troy) equals 2.5000000643 pennyweight.
How do I convert drams (apothecary/troy) to pennyweights?
Multiply the value in drams (apothecary/troy) by 2.5000000643 to get pennyweights.
How do I convert pennyweights back to drams (apothecary/troy)?
Multiply the value in pennyweights by 0.3999999897, or use the Pennyweight to Dram (apothecary/troy) converter.
How many pennyweights is 100 drams (apothecary/troy)?
100 drams (apothecary/troy) equals 250.0000064301 pennyweights, because 100 × 2.5000000643 = 250.0000064301.

Convert Dram (apothecary/troy) to other weight units

Show all Dram (apothecary/troy) conversions
Metric / SI (18 units)
Dram (apothecary/troy) to Attogram (ag) Dram (apothecary/troy) to Femtogram (fg) Dram (apothecary/troy) to Picogram (pg) Dram (apothecary/troy) to Nanogram (ng) Dram (apothecary/troy) to Microgram (µg) Dram (apothecary/troy) to Milligram (mg) Dram (apothecary/troy) to Centigram (cg) Dram (apothecary/troy) to Decigram (dg) Dram (apothecary/troy) to Gram (g) Dram (apothecary/troy) to Dekagram (dag) Dram (apothecary/troy) to Hectogram (hg) Dram (apothecary/troy) to Kilogram (kg) Dram (apothecary/troy) to Quintal (metric) (q) Dram (apothecary/troy) to Metric Ton (t) Dram (apothecary/troy) to Gigagram (Gg) Dram (apothecary/troy) to Teragram (Tg) Dram (apothecary/troy) to Petagram (Pg) Dram (apothecary/troy) to Exagram (Eg)
Avoirdupois (15 units)
Dram (apothecary/troy) to Grain (gr) Dram (apothecary/troy) to Dram (avoirdupois) (dr) Dram (apothecary/troy) to Ounce (oz) Dram (apothecary/troy) to Pound (lb) Dram (apothecary/troy) to Clove (clove) Dram (apothecary/troy) to Stone (US) (st) Dram (apothecary/troy) to Stone (UK) (st) Dram (apothecary/troy) to Quarter (US) (qr) Dram (apothecary/troy) to Quarter (UK) (qr) Dram (apothecary/troy) to Hundredweight (US) (cwt) Dram (apothecary/troy) to Hundredweight (UK) (cwt) Dram (apothecary/troy) to Wey (wey) Dram (apothecary/troy) to Kilopound (kip) (kip) Dram (apothecary/troy) to Ton (short, US) (sh tn) Dram (apothecary/troy) to Ton (long, UK) (long tn)
Troy & Apothecary (9 units)
Dram (apothecary/troy) to Point (1/100 carat) (pt) Dram (apothecary/troy) to Carat (metric) (ct) Dram (apothecary/troy) to Scruple (apothecary) (s ap) Dram (apothecary/troy) to Pennyweight (dwt) Dram (apothecary/troy) to Momme (mom) Dram (apothecary/troy) to Mace (mace) Dram (apothecary/troy) to Troy Ounce (oz t) Dram (apothecary/troy) to Tael (tael) Dram (apothecary/troy) to Pound (troy/apothecary) (lb t)
Indian / South Asian (6 units)
Dram (apothecary/troy) to Ratti (ratti) Dram (apothecary/troy) to Masha (masha) Dram (apothecary/troy) to Tola (tola) Dram (apothecary/troy) to Chittack (Chatank) (chittack) Dram (apothecary/troy) to Seer (Ser) (seer) Dram (apothecary/troy) to Maund (Mann) (maund)
Scientific / Atomic (9 units)
Dram (apothecary/troy) to Electron Mass (rest) (me) Dram (apothecary/troy) to MeV/c2 (MeV/c²) Dram (apothecary/troy) to Muon Mass (mµ) Dram (apothecary/troy) to Atomic Mass Unit (u) Dram (apothecary/troy) to Proton Mass (mp) Dram (apothecary/troy) to Neutron Mass (mn) Dram (apothecary/troy) to Deuteron Mass (md) Dram (apothecary/troy) to Carbon-12 Atom Mass (C-12) Dram (apothecary/troy) to Planck Mass (mP)
Astronomical (4 units)
Dram (apothecary/troy) to Lunar Mass (Moon) (M☾) Dram (apothecary/troy) to Earth's Mass (M⊕) Dram (apothecary/troy) to Jupiter Mass (MJ) Dram (apothecary/troy) to Sun's Mass (M☉)
Biblical / Ancient (14 units)
Dram (apothecary/troy) to Lepton (Biblical Roman) (lepton) Dram (apothecary/troy) to Quadrans (Biblical Roman) (quadrans) Dram (apothecary/troy) to Assarion (Biblical Roman) (assarion) Dram (apothecary/troy) to Gerah (Biblical Hebrew) (gerah) Dram (apothecary/troy) to Drachma (Biblical Greek) (drachma) Dram (apothecary/troy) to Denarius (Biblical Roman) (denarius) Dram (apothecary/troy) to Bekan (Biblical Hebrew) (bekah) Dram (apothecary/troy) to Didrachma (Biblical Greek) (didrachma) Dram (apothecary/troy) to Shekel (Biblical Hebrew) (shekel) Dram (apothecary/troy) to Tetradrachma (Biblical Greek) (tetra) Dram (apothecary/troy) to Mina (Biblical Greek) (mina) Dram (apothecary/troy) to Mina (Biblical Hebrew) (mina) Dram (apothecary/troy) to Talent (Biblical Greek) (talent) Dram (apothecary/troy) to Talent (Biblical Hebrew) (talent)
Force / Engineering (5 units)
Dram (apothecary/troy) to Poundal (pdl) Dram (apothecary/troy) to Ton (assay) (US) (AT) Dram (apothecary/troy) to Ton (assay) (UK) (AT) Dram (apothecary/troy) to Kilogram-force square second/meter (hyl) Dram (apothecary/troy) to Slug (slug)

Sources & references

Conversion factor (1 dr ap = 2.5000000643 dwt) verified against the following authoritative sources:

Results are provided for general reference. Verify critical measurements against an authoritative standard.