Weight Converter
Type a value on either side and the other updates instantly — swap the units anytime, or scan the table below to see the same weight in everything at once.
All units at once
The "From" value converted to every unit.
| Unit | Value |
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How this converter works
Every unit here is stored as a single factor relative to grams: a milligram is 0.001 g, a pound is exactly 453.59237 g, a stone is exactly 6,350.29318 g, and so on. Converting anything to anything else is two multiplications — value in the source unit times its factor gets you grams, then grams divided by the target unit's factor gets you the answer. These factors are the internationally defined values, not rounded approximations, so a result like 1 kg to pounds always comes out to the same precise 2.20462... every time.
Worked example
The default above converts 150 pounds to kilograms: 150 × 453.59237 ÷ 1,000 = 68.0389 kg. Flip it with the swap button and 68.0389 kg back to pounds returns to 150 — conversion and its inverse always round-trip cleanly because both directions use the same stored factor, just multiplying instead of dividing.
Frequently asked questions
How accurate are these conversions?
Exact, to the limits of floating-point math. Every unit converts through grams using the internationally defined factors — the pound is defined as exactly 453.59237 g, so it isn't a rounded approximation. Results here are the same numbers a calculator would give you, not a convenient estimate.
Is the ounce here the same as a troy ounce?
No — this is the everyday avoirdupois ounce (1/16 of a pound, 28.349523125 g), the one on a kitchen scale or a nutrition label. Precious metals like gold and silver are priced in troy ounces instead, which are heavier at about 31.1035 g. Mixing the two up is a classic mistake when pricing bullion — always check which ounce a source means.
What exactly is a stone, and why 14 pounds?
The stone is a traditional British and Irish unit, still used informally for body weight in the UK and Ireland, fixed by law at exactly 14 lb (6.35029318 kg). It has no metric-multiple relationship to the pound the way a kilogram does to a gram — 14 is just the historical value that stuck, which is why this tool stores it as a direct factor rather than deriving it from pounds.
Is a metric tonne the same as a US ton?
No, and this is a common source of error. This tool's "tonne" is the metric tonne — exactly 1,000 kg (about 2,204.6 lb). The US "short ton" is a different unit entirely, exactly 2,000 lb (about 907.2 kg) — roughly 10% lighter than a metric tonne. If you're working with US freight or steel-industry figures, double-check which one your source means.