The same bag of flour is quoted in ounces by a recipe, kilograms by a courier, jin at a Taiwanese market and pounds on a gym plate. This table holds seven common mass units — tonne, kilogram, gram, milligram, pound, ounce and the Taiwanese jin — with the kilogram as the base. Choose the unit your number is already in and the other six appear underneath at once. Everything runs in the browser, so the figure you type is never transmitted; the page around it still loads third-party resources such as advertising, which have nothing to do with what you weighed.
How to use it
- Type into the Value field, which starts at 1. Decimals are fine — 0.5 jin, for example.
- The From unit dropdown starts on Kilogram. Switch it to the unit your figure came in: reading 8 oz in an American recipe, pick Ounce.
- The result grid lists the remaining six units in one go, so there is no second dropdown. The button on each card copies that card's value.
- For the reverse direction, simply set From unit to what you were converting into. The Value field is not reset, so you can compare several directions in a row.
- With the field empty, every card shows a dash, and the copy button then yields an empty string rather than the dash itself.
When it comes in handy
Weigh ingredients from a US or UK recipe
Baking recipes ask for 8 oz of flour or 1 lb of butter. Eight ounces is 226.796184 g here and a pound is 0.45359237 kg. Watch for fl oz — a fluid ounce is a volume, and that conversion is not something this tool can do.
Shop with jin at a traditional market
One Taiwanese jin is fixed at 600 g, or 1.322773573 lb; the other way, a kilogram is 1.666666667 jin. "Half a jin" means 300 g. Stallholders in Taiwan almost always mean this jin, not the mainland Chinese one, so the two cannot be used interchangeably.
Post a parcel or check a baggage allowance
Airline checked-bag limits are usually written as 23 kg, which is 50.7063203 lb, while US domestic carriers quote 50 lb, which is 20.41165665 kg. Those are not the same limit, and the excess-weight fee lives in the gap.
Log workouts and body weight
An Olympic plate marked 45 lb is really 20.41165665 kg — 0.41 kg more than the 20 kg plate it sits next to, so two a side already puts you over 1.6 kg out. A body weight of 70 kg is 154.3235835 lb, ready to paste into an English-language training app.
Limits and behavior
- The ounce constant in the code is
0.028349523, while the international definition is 0.028349523125 kg — the trailing 125 is missing. The relative error is about four parts in a billion, invisible on any kitchen scale, but ten significant digits are enough to expose it: **16 ounces converts to 0.9999999956 pounds rather than exactly 1**, and 1 pound comes back as 16.00000007 ounces. When you need the two to agree exactly, work from the pound, whose 0.45359237 kg is the exact definition. - Ton here means the metric tonne of 1000 kg — not the US short ton (2000 lb, about 907.18 kg) nor the British long ton (2240 lb, about 1016 kg). One tonne shows as 2204.622622 lb, which is the quickest way to confirm you picked the right one. Freight quotes, carbon figures and harvest yields mix all three freely, and magnitude is usually your only clue.
- Precious metals are priced in troy ounces of 31.1034768 g, roughly 9.7% heavier than the avoirdupois ounce in this table. Running a gold quote through this converter undercounts by nearly a tenth, which is the most expensive mistake available in unit conversion.
- Not included: the stone (14 lb, still standard for British body weight), the Taiwanese tael (a sixteenth of a jin, 37.5 g), carats and grains. Nor is there any unit of force — newtons and kilogram-force are a different quantity, and everything here is mass.
- The smallest unit is the milligram; there are no micrograms. Doses printed as µg or mcg on a medicine leaflet need dividing by 1000 before you enter them as milligrams.
Frequently asked questions
Why does 16 ounces not come out as exactly 1 pound?
Because the ounce constant is truncated: the table stores 0.028349523 kg where the definition says 0.028349523125 kg. Sixteen of them make 0.453592368 kg, which divided by the pound's 0.45359237 kg gives 0.9999999956 — and the display carries ten significant digits, exactly enough to reveal it. This is a choice baked into the constant rather than floating-point noise; the same arithmetic in any language returns the same result. The impact is four parts in a billion, so groceries and parcels are entirely unaffected. Just do not use the converter to verify the definition — if you need "16 oz = 1 lb", take it from the definition itself.
Can I convert an ounce of gold with this?
No — you would be roughly 9.7% short. Precious metals and gemstones are traded in troy ounces of 31.1034768 g, whereas the ounce here is the avoirdupois ounce of 28.349523 g used for food, post and general goods. Feed a per-ounce gold price into this tool and the gram figure lands nearly three grams low, which at bullion prices is real money. The troy ounce is not in the table; multiply by 31.1034768 yourself if you need it.
Is the Taiwanese jin the same as the mainland Chinese jin?
It is not. The jin offered here is 600 g — sixteen taels of 37.5 g — as used in Taiwan, Kinmen, Matsu and some Hong Kong shops. The mainland market jin has been 500 g since the 1959 metric reform, divided into ten taels of 50 g. That is a 20% gap, and it bites hardest when you follow a Chinese-language recipe online: "one jin of pork" is 600 g in Taipei and 500 g in Beijing. This tool only knows the 600 g version, so halve a mainland jin into kilograms before entering it.
Tonne, ton, short ton, long ton — what is the difference?
A tonne, or metric ton, is 1000 kg and is the one stocked here. The US short ton is 2000 lb, about 907.18 kg; the British long ton is 2240 lb, about 1016 kg. Written simply as ton, which one is meant depends on the document and the country, with US sources usually meaning the short ton. The reliable test is the pound figure: a tonne is 2204.622622 lb, a short ton is a round 2000 and a long ton a round 2240. Container rates, emissions data and crop yields are the three places this goes wrong most often — when the magnitudes refuse to line up, suspect the ton first.
Does the pound-to-kilogram ratio change with location, or on the Moon?
No. All seven are units of mass, related by definition rather than by local gravity. Put a 70 kg person on the Moon and they are still 70 kg and 154.3235835 lb; what changes is the force they press onto the ground. Everyday "weight" blurs mass and force together — a scale actually measures force and converts it back — so as long as the scale is calibrated for the gravity where it stands, the reading agrees. Genuine force units such as the newton and kilogram-force are not in this table.