⚖️ oz to gr — Ounce to Grain Converter

Convert weight and mass units — kilograms, pounds, grams, ounces, tons, carats and more.

1 unit =
From
To
Formula 1 oz = 437.4923 gr
Quick Answer — Formula1 oz = 437.4923 grMultiply ounces by 437.4923 to get grains.Reverse: 1 gr = 0.002285755 oz
UnitNameValue
0.001 oz0.437492 gr
0.01 oz4.37492 gr
0.1 oz43.7492 gr
1 oz437.492 gr
5 oz2187.46 gr
10 oz4374.92 gr
50 oz21874.6 gr
100 oz43749.2 gr
1000 oz437492 gr

About Ounce to Grain Conversion

The Milligram (mg) and the Gram (g) are both units of weight & mass. Converting between them is straightforward using the formula above.

Formula: 1 oz = 437.4923 gr

This converter uses internationally recognized conversion factors. All calculations are performed client-side in your browser — no data is sent to any server.

Worked Examples: Ounce to Grain

A 1-carat diamond solitaire
1 oz = 437.4923 gr
The classic engagement ring stone is a 1-carat diamond = 0.2 g. Jewellers worldwide quote gemstone weight in carats and fractions of carats.
A large gemstone
5 oz = 2187.4614 gr
A 5-carat ruby is considered a fine specimen — it weighs just 1 gram, showing how small even prestigious gemstones truly are.
A tola of gold bar
1 oz = 437.4923 gr
A 1-tola gold bar (≈11.66 g) is the most common retail gold investment unit across India, Pakistan, and UAE.
A gem-quality sapphire
3 oz = 1312.4769 gr
A 3-carat blue sapphire weighs 0.6 g. The per-carat price of fine sapphires can exceed $10,000, so precise weight measurement is critical.

Ounce to Grain Reference Table

Ounce (oz)Grain (gr)Real-world context
0.1 oz43.7492284 gr
1 oz437.4923 grletter envelope
5 oz2187.4614 gr
10 oz4374.9228 gr
100 oz43749.2284 gr

Mental Math Tricks: Ounce to Grain

Round factor trick
Round 437.4923 to 437 for quick mental math. Error ≈ 0.1%.
Break factor into parts
Split 437.4923 as 437 + 0.4923 for easier mental arithmetic.
Use ×{approx} then adjust
Multiply by 437 first, then + 0.49×n.

When to Convert Ounce to Grain

💎 Jewellery Design Jewellers specify gemstone weights in carats and metal weights in grams or tola. Converting oz to gr is a core skill in jewellery making.
🏆 Gemstone Grading The 4Cs of diamond grading include carat weight. Converting between oz and gr helps compare stones across different grading systems.
💰 Gold Trading Gold prices are quoted per gram, per tola, and per troy ounce depending on the market. Ounce to Grain conversion is essential for traders and investors.
⚖️ Hallmarking Precious metal hallmarking authorities certify weights in specific units. Convert between oz and gr for compliance and documentation.
🎯 Archery & Ballistics Arrow and bullet weights are specified in grains. Converting to grams or vice versa is routine for archers and competitive shooters.
🏛️ Antique Appraisal Historical weights for silver and gold artefacts may be recorded in oz. Converting to modern gr helps calculate material value accurately.

Frequently Asked Questions — Ounce to Grain

1 ounce (oz) equals exactly 437.4923 grains (gr). Use the formula: oz × 437.4923 = gr.

To convert ounces to grains, multiply your value in ounces by 437.4923. For example, 5 oz × 437.4923 = 2187.4614 gr.

100 ounces = 43749.2284 grains. Calculation: 100 × 437.4923 = 43749.2284.

To convert grains back to ounces, divide by 437.4923 (or multiply by 0.00228575). Example: 10 gr ÷ 437.4923 = 0.02285755 oz.

Yes. This converter uses the internationally recognised exact conversion factor: 1 oz = 437.4923 gr. All calculations are performed in your browser with no rounding until display.

10 ounces = 4374.9228 grains. Simply multiply by 437.4923.

Converting ounces to grains is commonly needed for jewellery valuation, gemstone trading, precious metal buying and selling, and hallmarking compliance where one system uses oz and another uses gr.

Understanding Ounce and Grain

Ounce (oz)

The avoirdupois ounce (oz) equals exactly 28.349523125 grams or 1/16 of an avoirdupois pound. It is widely used in the US and UK for food portions, product packaging, and everyday measurements. Note that the troy ounce (31.1035 g), used for precious metals like gold and silver, is a different and heavier unit than the avoirdupois ounce.

Grain (gr)

The grain (gr) is the smallest unit in the avoirdupois, troy, and apothecary weight systems, equal to exactly 64.79891 milligrams (0.06479891 g). All three systems share the same grain as base: one avoirdupois pound = 7,000 grains; one troy pound = 5,760 grains. The grain is still used in ballistics (bullet and powder weights) and some pharmaceutical contexts.

History of the Ounce

The word "ounce" derives from Latin uncia (a twelfth), originally 1/12 of the Roman pound. The avoirdupois ounce developed in medieval England specifically for the wool trade, creating a 16-ounce pound distinct from the Troy 12-ounce pound. The British Imperial system codified the ounce in 1824. The modern exact definition (28.349523125 g) was set by the 1959 International Yard and Pound Agreement.

Interesting fact: A troy ounce (31.1 g) used for gold is heavier than an avoirdupois ounce (28.35 g) used for food — so an "ounce" of gold contains more metal than an "ounce" of flour. A standard large hen's egg weighs approximately 56–63 grams (about 2 oz).

History of the Grain

The grain is among the oldest measurement units in history, derived from the average weight of a grain of barleycorn (or wheat) — a practical standard used in ancient Egypt, Greece, and Rome. England formalised the barleycorn grain in the 15th century as the foundation of its weight system. The British Weights and Measures Act 1824 defined the grain, and the value remains unchanged today.

Interesting fact: The original grain was calibrated by laying dried barleycorns end-to-end — 32 grains equalled one inch in 13th-century England. Today, 9mm pistol bullets typically weigh 115–147 grains (7.5–9.5 g), and gunpowder charges are specified in grains for reloading.