If you've ever weighed a banana on a kitchen scale, you used the regular ounce — 28.35 grams. But every gold price you've ever seen quoted online is in a different ounce: the troy ounce, which is 31.1035 grams. That's 10% bigger. Why does gold get its own ounce?

A medieval mistake we kept

The troy ounce comes from Troyes, a medieval trade town in France where merchants standardised weights for precious goods. The system survived the modern metric switchover because it was already entrenched in bullion contracts. Centuries later, every gold quote on every news ticker still uses the troy ounce — even in countries that otherwise use grams for everything.

The three units you'll actually meet

  • Troy ounce (oz) — 31.1035 g. The international wholesale unit. Every CNBC ticker, every spot-price chart, every futures contract.
  • Gram (g) — 1 g. The retail unit in almost every country. You buy jewelry by the gram.
  • Tola — ~11.66 g. The traditional unit in India, Pakistan, Bangladesh, and parts of the Gulf. Equal to about ⅔ of a troy ounce. Old Mughal-era weight.

Quick conversions you should memorize

  • 1 troy ounce ≈ 31.1 g
  • 1 kilo (1000 g) ≈ 32.15 oz
  • 1 tola ≈ 11.66 g
  • 1 troy ounce ≈ 2.667 tolas

Worked example: if the international gold price is $2,400 per oz, then per gram it's $2,400 / 31.1 ≈ $77.17. A 5-gram pendant of pure 24K gold has a metal value around $386 — that's what the dealer paid; the price you see in the shop adds workmanship and margin on top.

Why this matters for buying

Retail prices in your country are quoted in grams, but the underlying spot price is in troy ounces and US dollars. Two layers of conversion happen behind the scenes:

  1. International spot ($/oz) → local currency ($/oz → EGP/oz or SAR/oz via the FX rate).
  2. Local currency per ounce → local currency per gram (divide by 31.1).

If the spot moves by 1% in dollars, your local-currency gram price moves by roughly 1% AS LONG AS the FX rate is stable. When the local currency weakens against the dollar, the per-gram price moves up even if gold itself didn't — that's how Egyptians watched gold "rally" in EGP terms during the 2022-2023 currency adjustments while it was actually flat in USD.

The headline international price isn't lying. The local price isn't lying. They're just measured in different units AND different currencies. Always check which one a quote is using before comparing.

For a gold watcher

DahabPro shows both sides on its insight pages: the international spot in USD/oz (what global money cares about) plus the local 24K per-gram price in your country's currency (what you actually pay). The split lets you see when a local move is "real gold" vs "currency-driven". Skipping that distinction is the biggest reason retail buyers misread their own market.