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Gold price conversion

Gold price per gram: convert the quote before comparing an offer.

A per-gram figure is a unit conversion from a documented reference price. It is not automatically the value of a karat item, a coin, or a buyer’s offer.

Calculate a gold itemFind a reference price

Quick answer: divide a documented gold price per fine troy ounce by 31.1034768 to express the same reference in price per gram. Keep its currency, source, quote type and timestamp attached to the converted number.

Gold price per gram formula

gold price per gram = documented gold price per troy ounce ÷ 31.1034768

A troy ounce is not an ordinary kitchen or postal ounce. The conversion constant is published by the U.S. National Institute of Standards and Technology in its precious-metals conversion material. Read the NIST conversion reference.

Use a documented input. This site does not display a live gold price. Capture the price source, the currency, whether it is bid/ask/midpoint/benchmark, and the time it was published before converting it.

Reference-price sources

Example conversion — not a current price

If a source reports a hypothetical gold reference of USD 2,500.00 per fine troy ounce, the converted reference is about USD 80.38 per fine gram:

USD 2,500.00 ÷ 31.1034768 = about USD 80.38 per fine gram

The example does not say what a retailer will charge for a bar, what a jeweler will pay for a ring, or what a refiner will settle. It only expresses the same source quote in another unit.

Pure-gold price versus karat-alloy value

The converted figure applies to fine gold. A karat item is an alloy, so its metal-only benchmark starts with its fine-gold fraction:

fine-gold grams = gross alloy grams × (purity percentage ÷ 100)

For example, an 18K / 750 item is nominally 75% gold by mass. A 10 gram item at that fineness contains a modeled 7.5 fine-gold grams before accounting for stones, springs, solder, non-gold fittings, testing uncertainty, or any resale value above metal content.

Use the gold purity guide to understand karat and fineness, then use the gold value calculator to keep the weight, purity, price basis and payout assumption visible.

Why a buyer’s number can differ

  • The source may quote a wholesale benchmark, bid, ask, midpoint, fixing, or futures contract rather than a retail transaction.
  • The buyer may test a different purity or exclude non-gold weight.
  • Assay, refining, shipping, settlement timing, fraud risk and margin can affect a scrap-style offer.
  • A coin, signed piece, antique, gemstone setting, or desirable jewelry item may be worth more intact than its contained gold.

A five-step comparison checklist

  1. Record the original quote exactly: source, currency, unit, price type and time.
  2. Convert only the unit; do not change the meaning of the quote.
  3. Determine whether the item’s weight and purity are actually known.
  4. Separate a theoretical contained-metal benchmark from a buyer’s real terms.
  5. Compare written offers using the same price time, net weight, fineness, fees and settlement conditions.

Educational calculation only: a per-gram conversion is not an appraisal, financial recommendation, or promise of a price. Laws, marks, taxes and buyer practices vary by jurisdiction.

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Source note

For the conversion constant, see NIST’s precious-metals conversion information. This page does not source or publish a live gold price.