Read a metal price chart: keep currency, weight and purity consistent
Compare stored metal prices on the same basis, distinguish missing observations from flat prices, and avoid using current exchange rates for the past.
Method
A price chart is useful only when its points measure the same thing. Before comparing dates, check the metal, currency, weight unit and selected purity. A troy ounce is 31.1034768 grams. It differs from the ordinary ounce used for many household weights.
For a pure-metal quote in USD per troy ounce, divide by 31.1034768 to obtain USD per gram. Apply a purity factor once when estimating an alloy. Our history chart follows the selected grade and weight unit; changing the item weight changes its estimated total value, not the underlying market quote.
Consider two hypothetical pure-metal quotes of 3000 and 3300 USD per troy ounce. These are teaching values, not recorded prices. They become about 96.45224 and 106.09746 USD per gram. The increase is 10% under either weight unit because both points use the same conversion factor.
View data
- Illustrative quote A
- 96.45224 USD/g 3000 / 31.1034768
- Illustrative quote B
- 106.097464 USD/g 3300 / 31.1034768
Worked example
Consider two hypothetical pure-metal quotes of 3000 and 3300 USD per troy ounce. These are teaching values, not recorded prices. They become about 96.45224 and 106.09746 USD per gram. The increase is 10% under either weight unit because both points use the same conversion factor.
Currency conversion can change the apparent return. Each historical point needs an exchange rate for the relevant date. Converting every old quote with today’s rate answers a different question. If date-matched rates are unavailable, view the stored USD history instead and keep the calculator’s chosen currency separate.
1 troy oz = 31.1034768 g
Illustrative quote A: 3000 / 31.1034768 = 96.45224 USD/g
Illustrative quote B: 3300 / 31.1034768 = 106.09746 USD/g
Change = (3300 − 3000) / 3000 × 100 = 10%
An empty range means sufficient observations are unavailable; it does not mean the price was zero or unchanged. Longer range buttons cannot create older records. Check the provider, timestamp and coverage, and distinguish spot estimates from dealer premiums, taxes and an actual sale quote.
View data
- Currency and date
- USD
- Weight unit
- 31.1034768 g/troy oz
- Purity applied once
- 18 / 24 = 0.75
Checks and limits
An empty range means sufficient observations are unavailable; it does not mean the price was zero or unchanged. Longer range buttons cannot create older records. Check the provider, timestamp and coverage, and distinguish spot estimates from dealer premiums, taxes and an actual sale quote.
Related calculators
Sources: NIST — SI conversion factors · European Central Bank — exchange-rate time series