Weight converter
Last updated
Type a weight once and read it in every unit. Most converters make you pick a "from" and a "to" and hand back a single number. The question is usually broader than that, so this shows all twenty-one at the same time.
Metric
- micrograms µg
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- milligrams mg
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- grams g
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- kilograms kg
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Avoirdupois — everyday weight
- standard ounces oz
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- pounds lb
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- stone st
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Troy — precious metals
- grains gr
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- pennyweight dwt
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- troy ounces ozt
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- troy pounds lb t
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Gemstone and pearl
- carats ct
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- ratti ratti
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- momme momme
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South Asia
- masha masha
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- tola tola
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East and Southeast Asia
- baht (Thai gold) baht
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- tael (Taiwan) tael
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- tael (Hong Kong) tael
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- tael (mainland China) tael
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- catty (Hong Kong) catty
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Tola and tael are market conventions, not defined standards. The three taels are genuinely different weights, so they are listed separately rather than averaged into one wrong answer.
Nothing you type here is sent anywhere. The arithmetic runs in your browser.
Every unit, in grams and in ounces
Every unit against the two the rest of this site is built on: the gram and the ounce. Most are exact by definition. Nine are trade conventions, and that difference matters more than it sounds.
| Unit | Symbol | System | In grams | In ounces | In troy ounces |
|---|---|---|---|---|---|
| micrograms | µg | Metric | 0.000001 | 3.53e-8 | 3.22e-8 |
| milligrams | mg | Metric | 0.001 | 3.53e-5 | 3.22e-5 |
| grams | g | Metric | 1 | 0.03527 | 0.03215 |
| kilograms | kg | Metric | 1000 | 35.274 | 32.151 |
| standard ounces | oz | Avoirdupois | 28.349523125 | 1 | 0.91146 |
| pounds | lb | Avoirdupois | 453.59237 | 16 | 14.583 |
| stone | st | Avoirdupois | 6350.29318 | 224 | 204.167 |
| grains | gr | Troy | 0.06479891 | 0.0022857 | 0.0020833 |
| pennyweight | dwt | Troy | 1.55517384 | 0.05486 | 0.05 |
| troy ounces | ozt | Troy | 31.1034768 | 1.0971 | 1 |
| troy pounds | lb t | Troy | 373.2417216 | 13.166 | 12 |
| carats | ct | Gemstone | 0.2 | 0.0070548 | 0.0064301 |
| tola | tola | Trade convention | 11.6638038 | 0.41143 | 0.375 |
| tael (Hong Kong) | tael | Trade convention | 37.79936375 | 1.3333 | 1.2153 |
| tael (mainland China) | tael | Trade convention | 50 | 1.7637 | 1.6075 |
| tael (Taiwan) | tael | Trade convention | 37.5 | 1.3228 | 1.2057 |
| catty (Hong Kong) | catty | Trade convention | 604.78982 | 21.333 | 19.444 |
| baht (Thai gold) | baht | Trade convention | 15.244 | 0.53772 | 0.49011 |
| momme | momme | Trade convention | 3.75 | 0.13228 | 0.12057 |
| masha | masha | Trade convention | 0.97198365 | 0.03429 | 0.03125 |
| ratti | ratti | Trade convention | 0.121497956 | 0.0042857 | 0.0039062 |
The units that are not standards
Nine of the twenty-one are market customs rather than defined units. They are real and heavily traded, but no standards body fixes them, and several vary by region. A converter that offers a single "tael" is giving most of its users the wrong number.
| Unit | Grams | In standard oz | In troy oz | What it actually is |
|---|---|---|---|---|
| tola | 11.6638038 | 0.4114 | 0.375 | A South Asian market convention equal to 3/8 of a troy ounce. Regional variants exist; this is the standard value used in the Indian and Pakistani bullion trade. |
| tael (Hong Kong) | 37.79936375 | 1.3333 | 1.2153 | Hong Kong tael — one sixteenth of a catty. Used in the Hong Kong gold trade. |
| tael (mainland China) | 50 | 1.7637 | 1.6075 | Mainland Chinese market tael, standardised to exactly 50 g. |
| tael (Taiwan) | 37.5 | 1.3228 | 1.2057 | Taiwanese tael, standardised to exactly 37.5 g. |
| catty (Hong Kong) | 604.78982 | 21.3333 | 19.4444 | The Hong Kong catty, 16 taels. It is the unit the Hong Kong tael divides from, which is why that tael has the value it does. Mainland and Taiwanese catties differ. |
| baht (Thai gold) | 15.244 | 0.5377 | 0.4901 | The weight Thai gold is bought and sold by. A one baht gold bar is 15.244 g. Ornament gold is sometimes quoted at a slightly lower baht weight, so check which is meant. |
| momme | 3.75 | 0.1323 | 0.1206 | Japanese, and still the standard weight for pearls worldwide. One momme is exactly 3.75 g, or one thousandth of a kan. |
| masha | 0.97198365 | 0.0343 | 0.0313 | One twelfth of a tola, used in South Asian jewellery for smaller amounts. Like the tola it is a trade custom rather than a defined standard. |
| ratti | 0.121497956 | 0.0043 | 0.0039 | One eighth of a masha, so one ninety-sixth of a tola. Historically a seed weight, and still used for gemstones in South Asia. Several regional variants exist. |
The tael is the clearest case. Hong Kong uses 37.799 g, mainland China exactly 50 g, and Taiwan exactly 37.5 g. Three units, one name, and a 33% spread between the widest pair. See the methodology for how we handle these.
Two ounces, two pounds
The table above lists ounces twice and pounds twice, and that is not a mistake. The avoirdupois ounce of 28.349523125 g governs food, post and body weight. The troy ounce of 31.1034768 g governs gold, silver and gemstones, and is 9.71% heavier.
The pounds reverse it. An avoirdupois pound holds sixteen ounces at 453.59237 g. A troy pound holds only twelve troy ounces, coming to 373.2417216 g, which makes it the lighter pound despite being built from the heavier ounce.
Trade units, and how they divide
These units are not arbitrary. Most are built from a larger one by simple division, and several trace back to the same troy ounce that governs gold everywhere else.
| Unit | Where it is used | Divides as | Grams | Ounces |
|---|---|---|---|---|
| Catty | Hong Kong | 16 taels | 604.78982 | 21.3333 |
| Tael | Hong Kong | 1⁄16 catty | 37.799364 | 1.3333 |
| Tola | India, Pakistan | 3⁄8 troy ounce | 11.663804 | 0.4114 |
| Masha | India, Pakistan | 1⁄12 tola | 0.971984 | 0.0343 |
| Ratti | India, Pakistan | 1⁄8 masha, 1⁄96 tola | 0.121498 | 0.0043 |
| Baht | Thailand | Gold bar weight | 15.244 | 0.5377 |
| Momme | Japan | 1⁄1000 kan | 3.75 | 0.1323 |
The tola shows the pattern best. It is three eighths of a troy ounce, which is why 11.6638038 g carries so many decimals: it inherits them. A Hong Kong tael is one sixteenth of a catty for the same reason. Divide far enough and most of these land back on a unit the rest of the world already uses. More on the tola →
Which system applies to what you are weighing
Most conversion mistakes are not arithmetic. They come from using the right number in the wrong system.
| If you are weighing | Use | Because |
|---|---|---|
| Food, ingredients, a parcel | Grams, or standard ounces | Every recipe, nutrition label and postal rate uses the avoirdupois ounce. |
| Gold, silver, platinum | Grams, or troy ounces | Spot prices are quoted per troy ounce worldwide. Your kitchen scale is not. |
| A diamond or gemstone | Carats | One carat is exactly 200 mg. Nothing else in the trade uses it. |
| Jewellery work in North America | Pennyweight | Jewellers still quote labour and scrap by the dwt, at 1/20 of a troy ounce. |
| Gold in India or Pakistan | Tola, or grams | The local trade prices by the tola, though receipts increasingly show grams. |
| Body weight in the UK or Ireland | Stone and pounds | 14 lb to the stone, and used almost nowhere else in the world. |
| Gold in Thailand | Baht | A one baht bar is 15.244 g, or 0.538 standard ounces. |
| Pearls | Momme | Japanese, and the worldwide standard for pearls. Exactly 3.75 g. |
| Medication or supplements | Milligrams or micrograms | Never ounces. The margin for error is far too small. |
When you are unsure, work in grams. A gram means one thing everywhere, which is exactly what the ounce does not. It is also why the metals trade increasingly quotes grams alongside troy ounces, and why professional recipes are written in them.
Frequently asked
How many grams are in a stone?
One stone is 14 pounds, or exactly 6350.29318 grams. That is 6.35 kilograms. The stone is still used for body weight in the United Kingdom and Ireland, and almost nowhere else.
How much does a carat weigh?
A metric carat is exactly 200 milligrams, or one fifth of a gram, fixed by international agreement in 1907. It measures gemstone weight. Do not confuse it with karat, spelled with a k, which measures the purity of gold and is not a weight at all.
How many grains are in a gram?
One gram is 15.4324 grains. A grain is exactly 64.79891 milligrams. It is the oldest unit here and the one the whole troy system is built from: 480 grains make a troy ounce and 24 make a pennyweight.
Why are there three different taels?
Because the tael is a trade custom rather than a defined standard, and different markets settled on different weights. A Hong Kong tael is 37.799 grams, a mainland Chinese market tael is exactly 50 grams, and a Taiwanese tael is exactly 37.5 grams. A converter offering a single tael is wrong for most of the people using it.
Can I type a compound weight like 1 lb 6 oz?
Yes. The converter reads compound amounts, fractions like 1/4 or one half written as a symbol, and it ignores any words around the number. So you can paste a line straight from a recipe or a shipping label.