How many grams in an ounce? The honest answer is: it depends on the ounce. Precious metals don’t use the kitchen-scale ounce (28.3495 grams). They use the troy ounce, which weighs 31.1035 grams — about 9.7% heavier. Every dealer, mint, and spot price quote runs on troy ounces, which is why a 1-ounce gold coin is heavier than a 1-ounce package of sugar. Below is the complete conversion chart between grams, ounces, and troy ounces, plus the math behind each unit, so you never have to second-guess a weight again.
How Many Grams in an Ounce?
A regular (avoirdupois) ounce equals 28.3495 grams. A troy ounce — the unit used for gold, silver, platinum, and palladium — equals 31.1035 grams. Most precious metals products are weighed in troy ounces or grams; the avoirdupois ounce only matters when you’re double-checking that a “1 oz” listing means what you think it means.
Use the chart below to convert between any common weight in either direction.
Conversion between grams, troy ounces, and avoirdupois (regular) ounces.
| Amount | Grams (g) | Troy Ounces (troy oz) | Avoirdupois Ounces (oz) |
|---|---|---|---|
| 1 g | 1.0000 | 0.0322 | 0.0353 |
| 5 g | 5.0000 | 0.1608 | 0.1764 |
| 10 g | 10.0000 | 0.3215 | 0.3527 |
| 20 g | 20.0000 | 0.6430 | 0.7055 |
| 31.1035 g (1 troy oz) | 31.1035 | 1.0000 | 1.0971 |
| 50 g | 50.0000 | 1.6075 | 1.7637 |
| 100 g | 100.0000 | 3.2151 | 3.5274 |
| 250 g | 250.0000 | 8.0377 | 8.8185 |
| 500 g | 500.0000 | 16.0755 | 17.6370 |
| 1,000 g (1 kg) | 1,000.0000 | 32.1507 | 35.2740 |
| 1 oz (avoirdupois) | 28.3495 | 0.9114 | 1.0000 |
| 10 troy oz | 311.0348 | 10.0000 | 10.9714 |
| 1 lb (16 oz) | 453.5924 | 14.5833 | 16.0000 |
Bookmark this table. The rest of this guide explains why these numbers exist and how to apply them when you’re looking at real coins, real bars, and real dealer listings.
What Is a Troy Ounce, and Why Don’t Precious Metals Use the Regular One?
A troy ounce is the standard weight unit for precious metals: 31.1035 grams. A regular avoirdupois ounce — the one used for food, mail, and most consumer goods in the U.S. — is 28.3495 grams. A troy ounce is about 9.7% heavier, which is why a 1-ounce gold coin doesn’t weigh the same as a 1-ounce package of coffee.
The split is historical. Troy weight is named for Troyes, France, an important trade-fair town in medieval Europe, and it standardized across the bullion and gemstone trade by the late Middle Ages. England formally adopted the Troy weight for gold and silver in the 1500s, and the U.S. carried the standard forward when it set up the Mint in 1792. Avoirdupois weight, meanwhile, became the everyday standard for general commerce — the system that survived in pounds, ounces, and grocery scales.
Today, the convention is universal. Every mint, refinery, and dealer in the world prices precious metals per troy ounce. The London Bullion Market Association (LBMA), which sets the global gold and silver benchmarks, quotes both metals in U.S. dollars per troy ounce. So does COMEX, the U.S. futures exchange where most paper gold and silver trades. The IRS uses the same unit when calculating capital gains on bullion, and so does every reputable dealer’s spot-priced quote engine. There is no parallel pricing system using avoirdupois ounces — the troy ounce stands alone as the unit of the trade.
The practical takeaway is short. When you see “$2,300/oz gold” on a dealer’s site, that’s $2,300 per troy ounce. If you treated it as a regular ounce and priced a Krugerrand (which contains 1 troy oz of gold) at the kitchen-ounce rate, you’d underpay by close to 10%. The math from here on assumes troy ounces, except where the chart explicitly distinguishes the two.
How Do You Convert Grams to Troy Ounces?
To convert grams to troy ounces, divide by 31.1035. To go the other direction, multiply troy ounces by 31.1035 to get grams. The full formulas are: troy oz = grams ÷ 31.1035, and grams = troy oz × 31.1035. Every conversion in this guide reduces to that one constant.
Worked examples for the weights you’re most likely to see on a dealer page:
- 100 g bar: 100 ÷ 31.1035 = 3.2151 troy oz
- 250 g bar: 250 ÷ 31.1035 = 8.0377 troy oz
- 500 g bar: 500 ÷ 31.1035 = 16.0755 troy oz
- 1 kg (1,000 g) bar: 1,000 ÷ 31.1035 = 32.1507 troy oz
Going the other way:
- 1 troy oz Eagle: 1 × 31.1035 = 31.1035 g
- 10 troy oz bar: 10 × 31.1035 = 311.035 g
- 400 troy oz Good Delivery bar: 400 × 31.1035 = 12,441.4 g (about 12.4 kg)
Mental shortcut: divide grams by 31, then trim a hair. A 100 g bar is “a touch over 3.2 troy oz.” A kilo is “a touch over 32 troy oz.” The shortcut is fine at the dealer counter; for receipts, taxes, or anything else you’ll record, use the full constant.
Common Bullion Sizes and What They Actually Weigh
Most precious metals products come in a handful of standard sizes. Grams dominate among smaller bars and rounds; troy ounces dominate among coins. Government mints and major refiners — PAMP, Valcambi, the Royal Canadian Mint, the Perth Mint — cooperate on these standards, so a stack from any reputable source converts cleanly into the same numbers.
Standard bullion sizes by grams, troy ounces, and typical use.
| Marketed Size | Grams | Troy Ounces | Typical Use |
|---|---|---|---|
| 1 g bar | 1 g | 0.0322 | Smallest fractional gold or silver bar; gift size |
| 5 g bar | 5 g | 0.1608 | Entry-level fractional bar |
| 10 g bar | 10 g | 0.3215 | Common fractional gold size |
| 20 g bar | 20 g | 0.6430 | European preference; Combibar standard |
| 1 oz coin (always troy) | 31.1035 g | 1.0000 | Eagle, Maple Leaf, Krugerrand, Philharmonic |
| 50 g bar | 50 g | 1.6075 | Mid-size collector bar |
| 100 g bar | 100 g | 3.2151 | Most popular mid-size bar globally |
| 10 oz bar (always troy) | 311.035 g | 10.0000 | Cost-efficient stacker bar |
| 1 kilo bar (“kilobar”) | 1,000 g | 32.1507 | Larger-balance stackers; lower premium per oz |
| 400 troy oz Good Delivery | ~12,441 g | 400.0000 | LBMA institutional standard; ~27.4 lbs |
A note on coin marketing: when bullion is sold as “1 oz,” it is always 1 troy oz. A 1 oz American Silver Eagle weighs 31.103 g. A 1 oz Krugerrand contains 1 troy oz of pure gold — though the coin’s gross weight is higher because it’s alloyed with copper. We unpack that distinction in the next section.
Pennyweight, Grains, and Other Units You’ll Still See
A handful of older weight units still circulate in specific corners of the precious metals world. None are common in modern bullion pricing, but you’ll run into them if you’re cashing out heirloom jewelry, reading historic coin specs, or buying from international dealers.
Pennyweight (dwt). Used by jewelers and pawn shops. One pennyweight equals 1.5552 grams, or 0.05 troy oz. Twenty pennyweights make one troy ounce. If a jeweler quotes you a “per pennyweight” buy price for scrap gold, multiply that price by 20 to compare against the troy-ounce spot rate.
Grain. The smallest unit you’ll see in this space. One grain equals 0.0648 grams, exactly, by definition. It’s used in firearms ballistics and historic U.S. coin specifications — the original 1792 silver dollar was specced at 416 grains.
Tola. A South Asian weight unit common in the Indian gold market. One tola equals 11.6638 grams, or about 0.375 troy oz. If you’ve inherited gold jewelry from family in India, Pakistan, or the Gulf region, you’ll see weights given in tolas.
Tael. A traditional Chinese weight, regional and inconsistent across markets. The most common modern version (the Hong Kong tael) is 37.4290 grams, or about 1.2034 troy oz. You’ll see it on Chinese gold bars sold for the Asian market.
The unit you’ll touch most often is pennyweight, mostly because U.S. pawn-shop scrap pricing still runs on it. The rest are mainly historical, but knowing they exist keeps you from being thrown by a dealer page.
What’s the Difference Between Pure Weight and Gross Weight?
Gross weight is the total weight of a coin or bar, including any alloy. Pure weight — sometimes called actual silver weight (ASW) or actual gold weight (AGW) — is the precious metal content alone. A 90% silver Morgan dollar weighs 26.73 grams gross but contains 24.06 grams (0.7734 troy oz) of silver. Both numbers are correct; they answer different questions.
The distinction matters whenever you’re calculating melt value or comparing premiums. Spot price applies to the pure metal content, not to the gross weight of the coin. Three quick examples:
1921 Morgan silver dollar. Gross weight 26.73 g; 90% silver. ASW = 0.7734 troy oz. At a silver spot of $30/oz (as of April 2026), the silver content is worth $23.20.
Pre-1965 silver quarter. Gross weight 6.25 g; 90% silver. ASW = 0.1808 troy oz, or about 5.62 g of silver. At $30/oz silver, that’s $5.42 in metal alone, before any numismatic premium.
Pre-1965 silver dime. Gross weight 2.50 g; 90% silver. ASW = 0.0723 troy oz. At $30/oz silver, that’s $2.17 in metal — meaningful for a coin with a 10¢ face value.
Modern bullion coins keep the math cleaner. A 1 oz American Gold Eagle, despite being only 91.67% gold (alloyed with silver and copper for durability), is specced to contain a full 1 troy oz of gold — its gross weight is 33.93 g. A 1 oz American Silver Eagle is 99.9% pure silver, gross weight 31.103 g. A 1 oz Canadian Maple Leaf in either gold or silver is 99.99% pure (“four-nines fine”), gross weight 31.103 g. When you buy modern bullion, the marketed weight is almost always the pure-metal weight; the alloy matters mainly for older U.S. coinage and certain European coins.
How Do You Convert Quickly Without a Calculator?
Three rules of thumb cover most situations at the dealer counter:
- 1 troy ounce ≈ 31 grams. Close enough for back-of-the-envelope. A 100 g bar is “a bit over 3 troy oz” (the exact answer is 3.2151).
- 1 kilo ≈ 32 troy ounces. A kilobar is roughly 32 troy oz of gold; the exact figure is 32.1507. If gold trades at $2,300 per troy oz, a kilobar’s metal value is roughly $73,500.
- Troy is about 10% heavier than avoirdupois. Multiply or divide regular ounces by 1.1 (precise ratio: 1.0971) to estimate the other unit. Useful when a non-bullion source mixes units.
These shortcuts are for ballpark estimation. Use the chart at the top of this article for receipts, tax records, cost basis tracking, or anything else where a 0.5% rounding error matters.
Tracking a Mixed-Unit Stack Without Losing Your Mind
Most people who own precious metals own them in more than one unit. A typical stack mixes 1 oz coins (American Eagles, Vienna Philharmonics), gram bars (a 100 g Valcambi here, a 50 g PAMP there), maybe a 10 oz bar or a kilobar, plus a junk silver bag priced by face value rather than weight at all. Calculating the total weight of metal in that stack — let alone the live market value — means running four conversions every time spot moves.
Spreadsheets handle it for a while. They stop scaling once you’ve added the seventh product, the third metal, and the realization that you also need cost basis and premium-paid columns for tax purposes. At that point the conversions are the easy part; the recordkeeping is where things break down.
A purpose-built tracker normalizes everything to one unit so you stop converting in your head. Gold Silver Ledger handles the unit problem with a single account-level setting: pick troy ounces, grams, or kilograms, and your entire portfolio renders in that unit across the holdings page, the analytics charts, and every report. Add a 1 oz Eagle, a 100 g Valcambi, and a kilobar to your stack; flip the display setting to grams; all three line up cleanly as gram weights. The conversions don’t go away — you stop being the one running them.
Conversion Chart FAQ
Is 1 ounce of gold the same weight as 1 ounce of sugar?
No. Gold and all other precious metals are weighed in troy ounces, which equal 31.1035 grams. Sugar and other consumer goods are weighed in regular avoirdupois ounces, which equal 28.3495 grams. A 1-ounce gold coin is about 9.7% heavier than a 1-ounce sugar packet on the same scale.
Why do precious metals use a different ounce?
Troy weight standardized for the bullion and gemstone trade in medieval Europe, centered on the trade fairs at Troyes, France. England formally adopted it for gold and silver in the 1500s, and the U.S. carried the standard forward when the U.S. Mint was founded in 1792. Avoirdupois weight became the everyday system for general commerce. The split has held for centuries because every mint, refinery, and exchange in the world now relies on it.
How many grams is a tola?
One tola equals 11.6638 grams, or about 0.375 troy oz. It’s the standard weight unit for gold in the Indian, Pakistani, and Gulf-region markets.
What’s a kilobar?
A kilobar is a 1,000-gram (1 kg) gold or silver bar. In troy ounces, that’s 32.1507 troy oz of metal. Kilobars are popular among larger-balance stackers because their premium over spot is typically lower per ounce than smaller bars.
Are dealer prices quoted per troy ounce?
Yes, always — for gold, silver, platinum, and palladium. The LBMA benchmarks, COMEX futures, and every retail dealer in the U.S. quote spot prices in U.S. dollars per troy ounce. Gram-priced products like 100 g bars are still derived from the troy-ounce spot price; the dealer multiplies spot by 3.2151 (the troy ounces in 100 g) and adds a premium.
How much is a gram of gold worth?
To find the metal value of one gram of gold, divide the current spot price by 31.1035. As of April 2026, with gold trading near $2,300 per troy ounce, a gram of pure gold contains about $74 of metal. Retail dealers add a premium on top — typically larger on small fractional sizes, smaller on bigger bars.
Do platinum and palladium use the same units?
Yes. Platinum and palladium are both quoted in U.S. dollars per troy ounce, the same as gold and silver. A 1 oz platinum American Eagle weighs 31.1035 grams; a 1 oz palladium Maple Leaf weighs the same. Whatever you’ve learned about Troy versus avoirdupois ounces for gold applies identically to the other two precious metals.
Why is a 1 oz American Gold Eagle heavier than 31.1 grams?
An American Gold Eagle is alloyed with silver and copper for durability — the coin is 91.67% gold (22-karat), not pure. To deliver a full 1 troy oz of gold, the U.S. Mint specs the coin’s gross weight at 33.93 grams. The extra 2.83 grams is the alloy. The gold content is still exactly 1 troy oz; the gross weight reflects the alloy that protects the coin from wear.
The Short Version
Conversion math gets dull fast — but only if you have to do it twice. Save this chart, learn the troy-ounce constant (31.1035 g), and you’ll have a reliable answer to “how many grams in an ounce” every time it comes up: at the dealer counter, on a tax form, or while sorting through a stack that grew faster than your spreadsheet did.
See Your Whole Stack in One Unit
Gold Silver Ledger displays your entire portfolio in whichever unit you prefer — troy ounces, grams, or kilograms. Eagles, kilobars, and 100 g rounds line up cleanly on a single holdings page, with cost basis and premium tracked per item. No spreadsheet math, no copy-pasting from a conversion chart.