How Many Grams Are in a Troy Ounce? Gold and Silver Calculator
One troy ounce equals 31.1034768 grams, usually rounded to 31.1035 grams for precious-metal comparisons. Multiply troy ounces by that factor to obtain grams; divide grams by the same factor to obtain troy ounces. Gold, silver, platinum, and palladium use the same mass conversion. An ordinary ounce is a different unit.
Key takeaways
- One troy ounce is approximately 31.1035 grams, not 28.35 grams.
- A gram measures mass; fineness describes composition.
- Use fine-metal weight when comparing a product with a metal quotation.
- Convert consistently, retain useful precision, and round only the displayed result.
Troy-ounce and gram calculator
Enter a non-negative weight and select the starting unit. The calculator converts mass only. It does not identify a metal, authenticate a product, deduct packaging weight, or calculate a live bullion price. The formulas and reference tables below remain available if interactive scripts are disabled.
Why a troy ounce differs from an ordinary ounce
The word “ounce” appears in more than one measurement system. Precious metals commonly use the troy system, while ordinary household and shipping weights generally use avoirdupois. Fluid ounces measure volume and should not be used to weigh bullion.
The NIST unit-conversion reference lists troy and avoirdupois ounces separately. A troy ounce is about 31.10348 grams; an avoirdupois ounce is about 28.34952 grams. The distinction is large enough to affect a purchase comparison materially.
If a kitchen scale has an “oz” button, do not assume it means troy ounces. Check the manual. Many scales label a troy-ounce mode “ozt,” but manufacturers can use different displays. When in doubt, record grams and convert deliberately using the correct factor.
The two conversion formulas
Grams = troy ounces × 31.1034768. For a two-troy-ounce item, multiply 2 by 31.1034768 to obtain 62.2069536 grams. Rounded to four decimal places, that is 62.2070 grams.
Troy ounces = grams ÷ 31.1034768. For a ten-gram item, divide 10 by 31.1034768 to obtain approximately 0.3215075 troy ounce. Rounded to four decimal places, that is 0.3215 troy ounce.
Keep the conversion factor separate from purity. If you are only converting the stated mass of a bar from grams to troy ounces, there is no reason to insert a fineness percentage into that step. Composition becomes relevant when calculating fine-metal content from a gross alloy mass.
Common troy-ounce weights in grams
| Stated troy ounces | Equivalent grams, rounded to four decimals |
|---|---|
| 1/10 | 3.1103 |
| 1/4 | 7.7759 |
| 1/2 | 15.5517 |
| 1 | 31.1035 |
| 2 | 62.2070 |
| 5 | 155.5174 |
| 10 | 311.0348 |
| 100 | 3,110.3477 |
These are mathematical conversions, not dimensional specifications or scale tolerances. A bar’s length and thickness depend on its metal, shape, and production method. A product sold for a stated fine-metal content may have a slightly different gross mass depending on composition and specification.
For format context, Agate’s bar sizes and purity guide helps connect the unit on a listing with the kind of product being purchased.
Common gram weights in troy ounces
| Stated grams | Equivalent troy ounces, rounded to six decimals |
|---|---|
| 0.5 | 0.016075 |
| 1 | 0.032151 |
| 2.5 | 0.080377 |
| 5 | 0.160754 |
| 10 | 0.321507 |
| 20 | 0.643015 |
| 50 | 1.607537 |
| 100 | 3.215075 |
| 1,000 | 32.150747 |
A kilogram is 1,000 grams, which is about 32.1507 troy ounces. It is not a hundred ounces, and a hundred-troy-ounce silver bar is not a kilogram bar. Read the unit even when two product photographs appear to show similar rectangular shapes.
Gold and silver use the same conversion
One troy ounce of gold and one troy ounce of silver have the same mass. Their physical volumes differ because the metals have different densities. That is why mass alone does not tell you how large a bar should look.
The same unit conversion applies to platinum and palladium. You do not need a different gram-to-ounce factor for each metal. You do need the correct metal reference price and fine-metal content when moving from a weight comparison to a value estimate.
Agate’s one-gram gold bar size guide addresses physical presentation. Use this conversion page for units, and use the exact refiner’s specifications for a bar’s dimensions.
Separate gross mass from fine-metal content
Gross mass is the total mass of the object being considered. Fine-metal content is the amount of the particular precious metal within it. Packaging adds a third measurement: the total mass of the bar or coin plus its holder, card, or shipping materials.
For an illustrative alloy sample weighing ten grams at 90% silver, the fine silver mass is nine grams. Dividing nine by 31.1034768 gives approximately 0.289357 troy ounce of silver. The remaining mass belongs to other constituents; it does not become extra silver because the sample is called a silver item.
By contrast, if an issuer already specifies that a coin contains one fine troy ounce of gold, that fine-gold amount is already the basis for the gold-content comparison. Do not multiply it by the alloy percentage a second time. Read whether the quoted amount describes fine metal or total object mass.
For older coins, use Agate’s silver coin melt-value chart to identify the relevant composition. Converting an unidentified coin’s mass does not establish how much silver it contains.
Compare a gram bar with a fractional coin
A one-gram gold bar is much smaller by stated metal mass than a one-tenth-ounce gold coin. One tenth of a troy ounce converts to about 3.11035 grams. Comparing the total price of the two without normalizing weight can make the gram bar seem cheaper for reasons unrelated to its premium.
For a weight-normalized price, divide the delivered purchase amount by the stated fine-metal weight in the same unit. Use price per fine gram for both or price per fine troy ounce for both. Keep packaging and collector features in the comparison as separate considerations.
Agate’s gram-bar versus one-tenth-ounce coin premium comparison develops that buying decision. The conversion establishes how much metal is involved; it does not determine which format fits every buyer.
Convert before comparing a metal quotation
Suppose a hypothetical ten-gram quantity of fine gold is compared with an illustrative gold reference of $2,000 per troy ounce. Divide ten grams by 31.1034768, then multiply the result by $2,000. The metal-reference calculation is approximately $643.01.
That is a teaching example, not today’s spot price, a retail price, or an offer to buy. A physical product can trade above or below a reference depending on the side of the transaction, premium, condition, and expenses. Applicable taxes and shipping also affect a delivered purchase amount.
The useful habit is to write the units beside each number. “10 g ÷ 31.1034768 g per ozt” produces troy ounces; multiplying by dollars per troy ounce produces dollars. If your units do not cancel in that way, review the calculation before relying on the result.
Avoid rounding and scale mistakes
Use the full factor for calculations and round at the end. Repeatedly converting a rounded answer back and forth can introduce small differences. Those differences are mathematical artifacts, not evidence that metal has been lost or gained.
Match displayed precision to the purpose. Four decimal places may be useful in a reference table, but a household scale does not necessarily measure that accurately. A calculator can display many digits even when the input measurement is approximate.
Never infer a tolerance from the final decimal shown on a product page. Authentication compares measurements with the exact product specification and appropriate equipment. A conversion calculator cannot certify that a bar falls within a producer’s manufacturing requirements.
A quick unit-check worksheet
Before comparing two products, record the following for each: metal, stated weight, weight unit, whether the amount is fine metal or gross mass, fineness if needed, and delivered price. Convert both to a common unit, then calculate cost per unit.
If a listing uses “oz” without clarifying the system, ask the seller. If the title and specification table disagree, do not select whichever number makes the product look better. Resolve the inconsistency before ordering. Clear units are a basic requirement for a meaningful bullion comparison.
For mixed orders, calculate each product’s fine-metal quantity separately before adding totals. Keep gold, silver, platinum, and palladium in separate columns. Adding their masses can describe a combined weight, but cannot produce one meaningful metal-value figure because each metal has its own reference price and product terms.
Frequently asked questions
How many grams are in a troy ounce of gold?
One troy ounce equals 31.1034768 grams, commonly rounded to 31.1035 grams. The factor is the same for gold, silver, platinum, and palladium because it converts mass units rather than metal composition.
Is a troy ounce the same as 28 grams?
No. An ordinary avoirdupois ounce is approximately 28.3495 grams. A troy ounce is approximately 31.1035 grams. Using 28 grams to estimate a troy-ounce bullion product understates its stated mass.
How many troy ounces are in a kilogram?
Divide 1,000 by 31.1034768. The result is approximately 32.150747 troy ounces. A kilogram bar and a hundred-troy-ounce bar therefore contain very different stated quantities.
Does a one-ounce gold coin always weigh exactly 31.1035 grams?
Not necessarily as a gross object. A coin advertised to contain one fine troy ounce of gold may include alloying metals and weigh more overall. Confirm whether the issuer’s weight statement refers to fine gold or total coin mass.
Can this calculator determine what my bullion is worth?
It converts mass only. A value estimate also needs verified composition, the appropriate current metal reference, and the product’s premium or buying bid. It does not authenticate an item or provide a guaranteed selling price.
Use one consistent conversion method for every product comparison. Identify the unit first, distinguish fine content from gross mass, and only then compare prices. That order prevents a simple measurement error from becoming an expensive buying mistake.
Educational content prepared September 15, 2026. Numerical price examples are hypothetical. Confirm current product and transaction details before acting.