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Convert between metric, carats, and grains.
⚖️ Covers both everyday weight (kg, lb, oz, stones) and precise mass units (carats for gemstones, grains for ammunition/medicine). Mass and weight share this one converter.
This tool converts between precise mass units — including carats (for gemstones and jewelry) and grains (for ammunition and historical medicine doses). Different from weight, which is technically a force.
Note: mass and weight share the same converter below — every unit (metric, imperial, carats, grains) is available in one place. For everyday body-weight conversions (kg ↔ lb), our Weight Converter shows the same tool. Switch any unit freely.
Different fields standardized on different bases historically. Jewelers use carats, ammo reloaders use grains, scientists use grams. This tool unifies them.
The Mass Converter converts mass converterfrom one unit to another using the exact internationally defined conversion factors. Type a value, choose your source and target units, and the converted result is shown instantly — no waiting, no page reload.
Manual conversion is error-prone because it means memorizing ratios (how many feet in a meter, how many pints in a liter). This tool removes that friction: the conversion factor is built in, and the math is done to full precision with no rounding until the final displayed number.
Common uses: people reach for this tool when they need to look up a kg to lbs body weight, grams to milligrams converter, carat to gram converter, or metric to imperial mass.
Browser-based tools like this one have a few real advantages over installed software or manual methods:
The Mass Converter is based on the following formula:
1 t = 1000 kg 1 kg = 1000 g 1 g = 1000 mg 1 carat = 0.2 g 1 grain = 0.06479891 g
Variables: mg = milligrams g = grams kg = kilograms t = metric tons (tonnes) carat = carats, gemstone mass grain = grains, 1 grain = 64.79891 mg
Metric mass steps by 1000: 1000 mg = 1 g, 1000 g = 1 kg, 1000 kg = 1 t. The carat is fixed at exactly 200 mg for gemstones, and the grain, once based on a barley grain, is now exactly 64.79891 mg (7000 grains = 1 pound).
Worked example: Convert 2.5 kg: g = 2.5 × 1000 = 2500 g t = 2.5 ÷ 1000 = 0.0025 t carats = 2500 × 5 = 12,500 ct grains = 2500 ÷ 0.06479891 ≈ 38,581 gr
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