Troy Ounce vs. Gram vs. Tola: The Complete Precious Metals Weight Conversion Guide

Quick reference: 1 troy ounce = 31.1034768 grams. 1 tola = 11.6638 grams. 1 gram = 0.0321507 troy ounces. Getting this conversion wrong is one of the most common — and costly — mistakes collectors make when comparing prices across markets.

Why Precious Metals Don't Use Regular Ounces

A troy ounce (31.1g) is different from the "avoirdupois" ounce used for everyday weight (28.35g) — a roughly 10% difference that has caused real confusion for centuries. Precious metals have used the troy system since medieval trade fairs in Troyes, France, and the convention stuck globally. If you ever convert bullion weight using a standard kitchen-scale ounce, your numbers will be wrong by about 10%.

Conversion Table

From	To	Multiply by
Troy ounces	Grams	31.1034768
Grams	Troy ounces	0.0321507
Tola	Grams	11.6638
Grams	Tola	0.0857
Troy ounces	Tola	2.6667
Kilograms	Troy ounces	32.1507

Where Each Unit Is Used

• Troy ounce — the international standard for spot price quotes (XAU/USD, XAG/USD) and most Western bullion products
• Gram — used for smaller bars, jewelry, and increasingly the default in apps and calculators for precision
• Tola — traditional unit across South Asia, the Middle East, and parts of Africa; still the primary retail unit in many local jewelry markets

A Costly Real Example

A collector compares a 10-tola gold bar priced at $7,600 against a 1oz coin priced at $2,480, assuming a tola is roughly the same as an ounce. It isn't — 10 tola = 116.638g = 3.75 troy oz. The correct per-ounce comparison is $7,600 ÷ 3.75 = $2,027/oz for the bar versus $2,480/oz for the coin — a very different conclusion than the naive comparison suggested.

The Safest Approach: Track Everything in Grams

Grams are the most precise, least ambiguous unit and convert cleanly to every other system. Recording every purchase in grams internally — regardless of which unit the dealer quoted — and converting for display only when needed eliminates rounding errors that compound across a large collection.

How BullionKeeper Handles This

Every holding is stored internally in grams and converted for display in whichever unit you prefer — troy ounces, grams, or tola — so the underlying math is always exact regardless of which unit a dealer or region quotes in.

Summary

• 1 troy oz = 31.1034768g — not the same as a standard 28.35g ounce
• 1 tola = 11.6638g — always convert before comparing tola and ounce prices
• Store everything in grams internally to avoid compounding rounding errors