Weight Converter

Weight conversions move between the metric units (gram, kilogram) and the imperial ones (ounce, pound, stone). The gram is the base here.

Metric:

• 1 gram = 1,000 mg = 0.001 kg

Imperial:

• 1 ounce = 28.3495 g
• 1 pound = 453.592 g (16 ounces)
• 1 stone = 6,350.29 g (14 pounds)

Quick cross-system:

• 1 kg = 2.20462 lbs
• 1 lb = 0.453592 kg

For a sense of scale:

• A paperclip: about 1 g
• A smartphone: 170–200 g
• A liter of water: exactly 1 kg
• An average adult: about 70 kg (154 lbs, or 11 stone)

The stone still rules personal body weight in Britain and Ireland, where people say “eleven stone” the way Americans say “154 pounds.” It throws off travelers because it shows up almost nowhere else.

The real trap is the ounce, because there are two completely different ones. The weight ounce (28.35 g) measures mass; the fluid ounce measures volume. A recipe calling for “8 oz of flour” (weight) and “8 fl oz of milk” (volume) wants two unrelated quantities that happen to share a name. They only line up for water, where one fluid ounce weighs almost exactly one ounce, which is the historical coincidence that started the whole muddle.