Troy Ounces to Kilograms Converter

What this converter does

It converts troy ounces to kilograms by multiplying by exactly 0.0311034768. Holdings, trades and deliveries of precious metal are counted in troy ounces; vaults, shipping documents and customs entries record kilograms. This conversion sits between the position and the pallet, and it is needed far more often than the ounce-to-gram version once quantities grow beyond a few coins.

The formula

Multiply troy ounces by exactly 0.0311034768. That constant is the troy ounce of 31.1034768 grams expressed in kilograms, and it is exact because the troy ounce is defined as 480 grains and the grain is exactly 64.79891 milligrams. The reverse divides by the same figure, and a round trip returns your starting value precisely.

Worked examples

One troy ounce is 0.0311 kg. A hundred troy ounces is 3.11 kg. A thousand is 31.10 kg — a common silver bar size, and about as much as one person can comfortably carry. The large gold bars traded in London are nominally 400 troy ounces, which is about 12.44 kg; the permitted range is wider than the nominal figure, so each bar carries its own assayed weight and 400 describes a convention rather than a mass every bar meets exactly.

Why the kilogram figure matters

Because physical metal has to move, and everything involved in moving it is metric. Freight is charged by the kilogram. Customs declarations demand metric mass. Vault records, insurance schedules and security arrangements all work in kilograms because that is what the rest of the logistics world uses. A position expressed purely in troy ounces cannot be shipped, insured or declared without this conversion, which is why it appears at every point where paper metal becomes physical metal.

Gold and silver at the same scale

The troy ounce is a unit of mass and is identical for every metal, so the conversion here does not change between gold and silver. What changes is the practical scale. A significant gold holding might be a few hundred troy ounces, which is a few kilograms and fits in a small box. The same value in silver is tens of thousands of troy ounces, which is hundreds of kilograms and needs a pallet. The unit is the same; the logistics are entirely different, and that difference is why silver figures cross into kilograms and tonnes far more readily than gold ones.

Fine weight against gross weight

A troy ounce of alloyed metal is a troy ounce of mass, only part of which is precious metal. Refined bullion at 999.9 fineness is effectively all metal, so gross and fine weights coincide for practical purposes. Jewellery and coinage are different: a 22-karat coin containing one troy ounce of fine gold weighs more than 31.10 g in total, because the alloy adds mass. Converting a gross weight and treating it as fine content overstates the metal, and no unit conversion can catch that error because both figures are legitimate masses.

Precision for holdings

Three decimal places of a kilogram is a gram, which is well within what any bullion scale resolves and represents real value at precious-metal prices. For a shipping document two decimals is usually sufficient; for a valuation, keep the full figure through the calculation and round once at the end. The standing rule across this cluster applies with particular force here: rounding early, in a chain that includes a price, turns a display decision into a monetary one.

Common mistakes

Using the avoirdupois ounce, which is 9.7 percent lighter and produces a kilogram figure short by that margin. Treating a nominal bar weight as an exact one when the assay certificate says otherwise. Confusing fineness with mass. And converting a troy pound as though it were twelve avoirdupois ounces — the troy pound is twelve TROY ounces, which is a different quantity, and it has its own pages in this cluster.

Benchmarks

1 oz t is 0.0311 kg. 10 oz t is 0.311 kg. 32.1507 oz t is about 1 kg. 100 oz t is 3.110 kg. 400 oz t is about 12.441 kg. 1,000 oz t is 31.103 kg. 32,150.7 oz t is about 1 tonne. The kilogram at 32.15 troy ounces is the anchor, and every other figure on the list follows from it.

Accuracy and limits

Exact factor, exact decimal arithmetic, display-only rounding, and refusal of ambiguous input with an explanation. The tool converts mass. Fineness, assay, spot price and the difference between gross and fine weight are all outside what a unit converter can supply, and this page names them rather than folding them in silently.

Vault records and audit

Metal held in a vault is recorded by bar, each with a serial number, an assayed weight and a fineness. The holding in troy ounces is a sum over those bars, and the kilogram figure is what the physical inventory and the insurance schedule use. An audit reconciles three things: the bar list, the weighed total and the reported position, and any discrepancy has to be traceable to a specific bar rather than absorbed into a rounding. Keeping both units per bar makes that reconciliation possible.

Why bar weights are never round

Large bars are poured rather than machined to a target, so their weights land wherever the pour lands and are then assayed. That is why a nominal 400-ounce bar might assay at 402.35 troy ounces, and why the certificate rather than the nominal name governs. Converting the nominal figure gives a planning number; converting the assayed figure gives the real one, and only the second belongs in a settlement.

A quick magnitude check

Troy ounces divided by 32 approximates the kilograms closely: a thousand ounces gives about 31.25 against a true 31.10. The approximation runs half a percent high and is ideal for catching a misplaced decimal, which is the error that actually causes trouble at this scale. For anything settled in money, the exact constant is what the tool applies.

Declaring metal at a border

Customs entries want a metric mass and a description, and the troy ounce figure that governs the commercial side has no standing on the form. Converting the assayed troy weight gives the declared kilogram figure, and the two should be recorded together on the shipping file so that a later query can be answered without re-deriving anything. Where a consignment is several bars, the declaration total is the sum of assayed weights rather than a nominal count multiplied out — a distinction that matters because nominal and assayed totals will differ.