Compare gold bar weights from 1 gram to 1 kilogram and London Good Delivery bars. Convert troy ounces and calculate fine gold content correctly.
- There is no single gold-bar weight: retail bars span grams, ounces and kilograms.
- One troy ounce equals exactly 31.1034768 grams—not the 28.35-gram household ounce.
- London Good Delivery gold bars contain 350–430 fine troy ounces, so '400 oz' is a convention, not an exact universal weight.
- One troy ounce equals exactly 31.1034768 grams.
- Common retail sizes include 1 g, 5 g, 10 g, 1 oz, 100 g, 10 oz, 500 g and 1 kg.
- A nominal “400 oz” institutional bar is not required to weigh exactly 400 troy ounces.
- Fine gold content equals gross weight multiplied by fineness.
- Smaller bars improve divisibility; larger bars may reduce unit premium but concentrate custody and resale.
There is no single standard gold-bar weight
The cinematic brick held by central banks is only one part of the market. Retail investors also encounter thin minted gram bars, one-troy-ounce bars, compact cast 100-gram bars and dense kilogram bars.
Answering “how much does a gold bar weigh?” correctly therefore requires two details: which bar format, and whether the quoted number is gross mass or fine gold content.
Common gold bar weights
| Labeled size | Grams | Troy ounces | Typical context |
|---|---|---|---|
| 1 gram | 1 g | 0.03215 oz t | Small minted retail bar; high divisibility |
| 5 grams | 5 g | 0.16075 oz t | Gift and entry-size retail format |
| 10 grams | 10 g | 0.32151 oz t | Compact metric retail bar |
| 1 troy ounce | 31.1034768 g | 1 oz t | Widely recognized bullion size |
| 100 grams | 100 g | 3.21507 oz t | Mid-size metric bar |
| 10 troy ounces | 311.034768 g | 10 oz t | Larger retail/stacking format |
| 500 grams | 500 g | 16.07537 oz t | Large metric retail bar |
| 1 kilogram | 1,000 g | 32.15075 oz t | Large retail and professional format |
Physical dimensions are not universal. Cast and minted bars with the same mass can have different length, width, thickness and corner profiles. For authentication, compare the exact refiner and product specifications rather than a generic size chart.
Troy ounces are not household ounces
Precious metals use the troy ounce. The National Institute of Standards and Technology lists the troy ounce at approximately 31.10348 grams, and NIST conference materials publish the exact conversion used here: 31.1034768 grams.
The ordinary avoirdupois ounce used for food and household goods is about 28.35 grams. If a kitchen scale is set to “oz,” it may display avoirdupois ounces and create an error of almost 10%. Use grams or a verified troy-ounce mode.
How much does a London Good Delivery gold bar weigh?
The London Bullion Market Association specifies gold content of at least 350 and at most 430 fine troy ounces. That is approximately 10.9–13.4 kilograms of fine gold. The familiar 400-troy-ounce figure is a market convention near the middle of an allowed range.
LBMA weighing procedures distinguish gross bar weight from fine gold content. The gross bar is weighed in troy ounces, while fine content depends on the bar’s fineness. A bar near 400 fine troy ounces corresponds to about 12.44 kilograms of fine gold, but an eligible Good Delivery bar need not equal that exact number.
Gross weight, fineness and fine gold
A bar marked 100 g and 999.9 fineness is not described mathematically as 100.000 g of pure gold. The nominal gross mass is multiplied by 0.9999 to estimate fine-gold mass. Accredited product tolerances and official certificates govern a specific bar.
For value, multiply fine troy ounces by a timestamped spot reference, then separately account for the product premium, dealer spread, shipping, tax where applicable and future resale terms. Do not multiply gross ounces by spot without checking the unit and fineness.
Which gold bar weight is practical?
| Priority | Usually favors | Why | Check before buying |
|---|---|---|---|
| Small partial resale | Multiple smaller bars | You can sell part without liquidating one large position | Higher premium per fine ounce |
| Lower unit premium | Larger retail bars | Manufacturing and packaging costs are spread over more metal | Dealer buyback, assay expectations and buyer depth |
| Easy verification | Recognized refiner/product with intact documentation | Specifications and market familiarity reduce friction | Packaging is evidence, not absolute proof |
| Home handling | Sizes matched to rated safe and insurance | One kilogram of gold is compact but financially concentrated | Policy limits, disclosure rules and access security |
| Institutional settlement | Good Delivery system | Wholesale custody and chain-of-integrity infrastructure | Not the normal retail take-home product |
- Compare total cost per fine troy ounce, not only the bar’s sticker price.
- Request the dealer’s current buyback for the same brand, size and condition.
- Confirm whether opened assay packaging changes resale procedure.
- Check safe shelf load, deposit-box limits, vault fees and insurance wording.
- Decide how much you might need to sell at one time.
- Record serials and invoices separately from the storage location.
Do cast and minted bars of the same weight feel different?
Yes, even though the scale should show the same nominal mass. A minted bar is cut or stamped to a controlled format and usually has sharper edges, a smooth face and retail packaging. A cast bar is poured into a mold, so surface texture, taper and exact dimensions can vary. Gold’s high density makes both surprisingly compact.
Manufacturing style does not change the troy-ounce conversion, but it can change handling and resale procedure. A sealed minted bar may be checked against an assay card and product dimensions; a cast bar may rely more heavily on refiner marks, serial records, weighing and professional testing. Neither packaging nor appearance is proof by itself.
Do not file, drill or cut a bar simply to confirm weight. Start with the invoice, exact product specification, a calibrated scale and non-destructive checks. If the dimensions, mass or markings disagree, preserve the evidence and use an independent bullion professional.
This guide explains units and product formats. It is not personalized investment, tax or legal advice and does not recommend a specific bar size or seller. Prices, premiums, spreads, taxes, insurance and custody terms change; verify current written terms for your jurisdiction and transaction.
A label such as “1 kg” does not reveal every resale detail. Brand recognition, bar type, fineness, serial records, packaging, chain of custody and local dealer procedures can affect verification and liquidity even when two bars have the same fine-gold content.
The useful number is not the heaviest bar you can buy. It is the amount of fine gold in a unit you can verify, store securely and resell without creating an impractical all-or-nothing decision.
Video walkthrough: Video context: the LBMA introduces the Good Delivery system behind wholesale gold bars.
Bottom Line
Gold bars range from gram products to wholesale bars containing hundreds of fine troy ounces. Use 31.1034768 grams per troy ounce, distinguish gross mass from fine content and treat “400 oz” as a convention within the LBMA’s 350–430-fine-ounce range. Then choose a size around real storage and resale needs.
FAQ: Gold Bar Weights
How much does a standard gold bar weigh?
There is no universal standard retail weight. The famous wholesale London Good Delivery bar contains 350–430 fine troy ounces, while retail bars commonly range from 1 gram to 1 kilogram and beyond.
Does a gold bar weigh 12.4 kg?
A nominal 400-fine-troy-ounce bar corresponds to about 12.44 kg of fine gold. Actual Good Delivery bars may contain 350–430 fine troy ounces, so 12.4 kg is a convention, not an exact rule.
How many grams are in a troy ounce of gold?
One troy ounce equals exactly 31.1034768 grams. It is heavier than the ordinary avoirdupois ounce used for most household goods.
How much pure gold is in a 1 kg 999.9 bar?
Using the nominal figures, 1,000 g × 0.9999 equals 999.9 g of fine gold, or about 32.1475 fine troy ounces. Refer to the product certificate and tolerances for a specific bar.
Are smaller or larger gold bars easier to sell?
Recognized small bars offer divisibility and may attract more retail buyers; larger bars may have lower unit premiums but concentrate value and can require more demanding verification. Local dealer depth matters.
Sources and verification
Use these primary and specialist references to verify the technical, legal or market framework behind the guide.
- LBMA — London Good Delivery: Gold and Silver — Official wholesale bar requirements, including 350–430 fine troy ounces.
- LBMA — Annex B: Weighing, Packing and Delivery — Official gross-weight weighing procedures and kilogram equivalents.
- LBMA — About Good Delivery — Explains accredited refiners and the approximate 400-troy-ounce convention.
- NIST — Guide to the SI, Appendix B.8 — Official conversion: one troy ounce equals 31.10348 grams to the listed precision.
- NIST SP 1226 — Publishes the 31.1034768-gram troy-ounce conversion.
- CFTC/FINRA — 10 Things to Ask Before Buying Physical Metals — Compare weight, spot basis, premium, spread and fees.
- LBMA — Good Delivery video — Official visual context for the wholesale Good Delivery system.
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