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Convert Kilogram to Obolus (kg to ob) instantly with accurate, readable results.
Use our Mass Unit Converter to convert between grams, kilograms, pounds, ounces, and other weight units instantly. Designed for cooking, science, fitness, and engineering needs, this unit conversion tool offers accurate results between metric and imperial systems. Whether you’re tracking body weight, measuring ingredients, or handling heavy machinery, our mass unit conversion calculator has you covered.
Kilogram (kg) — the SI base unit of mass
It is defined by fixing the Planck constant at exactly 6.62607015×10⁻³⁴ J·s; together with the definitions of the meter and second, this sets the kilogram. Used worldwide for measuring mass in science, engineering, commerce, medicine, food, shipping, and everyday life.
- Symbol: kg
- System: SI base unit for mass
- Exact relations: 1 kg = 1000 g = 1,000,000 mg
- Imperial equivalents (derived from 1 lb = 0.45359237 kg exactly): 1 kg ≈ 2.20462 lb ≈ 35.27396 oz
- Typical examples: 1 liter of water ~1 kg; a laptop ~1.5 kg; an adult person ~70 kg.
Obolus (obol) — a historical unit of mass equal to 10 grains
It is commonly treated as half a scruple, or 10 grains, in historical Roman and apothecaries’ weight contexts; because the obolus was also a coin and ancient weight term, its exact value can vary by period and region. Used mainly in historical medicine, pharmacy, numismatics, and references to ancient or apothecaries’ measures.
- Symbol: obol, obolus
- System: Historical Roman and apothecaries’ unit for mass
- Exact relations: 1 obolus = 1/2 scruple = 10 gr = 647.9891 mg
- Metric equivalents: 1 obolus = 0.6479891 g ≈ 0.000647989 kg
- Typical examples: historical prescriptions may mention oboli; 2 oboli equals scruple; 1 obolus is a little less than 2/3 of a gram.