Scruples to Grams Converter

Convert between scruples and grams (g) using the exact apothecary & troy weight relationships. The tool also gives equivalent grains, drams and troy ounces, making it ideal for historical pharmacy, precious metal assays and archival work.

Calculation engine based on 1 scruple = 20 grains and 1 grain = 0.06479891 g → 1 scruple = 1.2959782 g.

Scruples ⇄ grams conversion

Apothecary / Troy
Conversion direction

Useful for historical prescriptions, assay notes and troy-based laboratory records.

Results

Scruples:
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Grams (g):
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Grains (gr):
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Drams (ʒ):
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Troy ounces (ozt):
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Enter a value and click “Convert” to see equivalent scruples, grams, grains, drams and troy ounces.

Scruples to grams – quick reference table

Common scruple values with their gram, grain, dram and troy-ounce equivalents. Handy when checking historical recipes or converting assay notes without a calculator.

Scruples Grams (g) Grains (gr) Drams (ʒ) Troy ounces (ozt)

Based on 1 scruple = 20 grains, 1 grain = 0.06479891 g, 3 scruples = 1 dram, 24 scruples = 1 troy ounce. Values are rounded for readability.

What is a scruple (apothecary & troy unit)?

The scruple is a historical unit of mass used in apothecary and troy weight. It appears in old pharmacy recipes, medical formularies and precious metal documentation. In its modern standardized form:

Exact relationships

1 scruple = 20 grains

1 grain = 0.06479891 g

⇒ 1 scruple = 20 × 0.06479891 g = 1.2959782 grams

In the apothecary system the scruple is part of a wider hierarchy:

  • 3 scruples = 1 dram (ʒ)
  • 8 drams = 1 ounce
  • 12 ounces = 1 pound

These relationships are compatible with the troy ounce used for precious metals: 1 ounce = 24 scruples = 480 grains, which matches the 480-grain troy ounce.

Formulas used by the scruples ⇄ grams calculator

Scruples to grams

Formula

Let mscr be the mass in scruples.

grams = m_scr × 1.2959782

Example: 4 scruples → 4 × 1.2959782 ≈ 5.1839 g.

Grams to scruples

Formula

Let mg be the mass in grams.

scruples = m_g ÷ 1.2959782

Example: 6 g → 6 ÷ 1.2959782 ≈ 4.63 scruples.

Derived conversions: grains, drams, troy ounces

From scruples

  • Grains: grains = scruples × 20
  • Drams: drams = scruples ÷ 3
  • Troy ounces: ozt = scruples ÷ 24

These follow directly from the standard apothecary/troy structure and are applied automatically by the tool.

Worked examples

Example 1 – Convert 9 scruples to grams, grains, drams and ounces

  1. Grams: 9 × 1.2959782 ≈ 11.6638 g.
  2. Grains: 9 × 20 = 180 grains.
  3. Drams: 9 ÷ 3 = 3 drams.
  4. Ounces (troy/apothecary): 9 ÷ 24 = 0.375 ozt.

Example 2 – Convert 3.5 g of a legacy preparation to scruples

  1. Scruples: 3.5 ÷ 1.2959782 ≈ 2.702 scruples.
  2. Grains: 2.702 × 20 ≈ 54.0 grains.
  3. Ounces: 2.702 ÷ 24 ≈ 0.1126 ozt.

Professional use and limitations

Today, the apothecary system has largely been replaced by SI units (grams, milligrams), but scruples still appear in:

  • historical pharmacopoeias and prescriptions,
  • older scientific and medical literature,
  • precious metal assays and archival records,
  • numismatics and restoration of historical instruments.

This scruples to grams converter is designed as a bridge between historical documentation and modern metric practice. For any regulated pharmaceutical or legal-metrology context, always rely on current national standards and calibration procedures; use scruple-based conversions only when you are explicitly dealing with legacy material.

Frequently asked questions about scruples and grams

Is the scruple still an official unit today? ▾
In modern practice, the apothecary system (including scruples and drams) has been superseded by the metric SI system in medicine and pharmacy. However, the unit is still defined and consistent through the grain, which is widely used in ballistic and precious metal contexts. For new formulations, grams and milligrams should always be preferred.
Are apothecary and troy scruples different? ▾
Historically the apothecary and troy systems share the same basic grain-based hierarchy, so the scruple is the same in both: 20 grains. This calculator therefore uses a single, consistent factor of 1 scruple = 1.2959782 g for both contexts.
How many milligrams are in a scruple? ▾
Since 1 scruple = 1.2959782 g, this corresponds to approximately 1295.9782 mg. Many historic recipes round to 1.30 g or 1300 mg, but the calculator keeps more digits internally to limit cumulative rounding errors.
Can I use this tool to re-create old pharmacy recipes safely? ▾
The converter provides mathematically correct unit conversions, but it does not account for modern safety, efficacy or regulatory requirements. If you are working with active substances, re-formulation must be done under the supervision of a qualified professional and according to current pharmacopoeial standards.
Is this scruples to grams converter accurate enough for precious metals? ▾
Yes. Because the conversion is based on the exact grain definition, it is fully compatible with troy ounce calculations used in bullion trading and assay reports. For high-value operations, ensure your weighing instruments are properly calibrated and that rounding rules are explicitly documented.