Gold Price Calculator
Calculate the value of gold by weight, karat and spot price. Enter grams, ounces or tola plus purity to get the melt value, price per gram and total worth.
Updated 2026-06-14 · Free · No sign-up · Runs privately in your browser
Show the formula & steps
How the Gold Price Calculator Works
This tool finds the value of gold based on its weight, purity (karat) and the current spot price. Enter a weight in grams, troy ounces, pennyweight, tola or kilograms, choose the karat, and type today’s spot price per troy ounce. It returns the pure gold content, the price per gram and the total melt value.
The Formula
Only the pure gold in an item carries metal value, and gold is priced per troy ounce:
Pure content (troy oz) = weight in troy oz × (karat ÷ 24) Value = pure content (troy oz) × spot price per troy ounce
One troy ounce is 31.1035 grams. Karat purity is the karat number divided by 24, so 18K is 18 ÷ 24 = 0.75.
Worked Example
For 10 grams of 18K gold with a spot price of $2,300 per troy ounce:
- Weight in troy oz = 10 ÷ 31.1035 = 0.3215 troy oz
- Purity = 18 ÷ 24 = 0.75 (75%)
- Pure content = 0.3215 × 0.75 = 0.2411 troy oz
- Value = 0.2411 × $2,300 = ≈ $554.50
Purity Quick Reference
| Karat | Gold purity | Common use |
|---|---|---|
| 24K | 99.9% | Bullion, bars |
| 22K | 91.6% | Coins, Asian jewelry |
| 18K | 75.0% | Fine jewelry |
| 14K | 58.3% | Everyday jewelry (US) |
| 10K | 41.7% | Budget jewelry |
Spot Value vs. Selling Price
The calculator gives the melt value at the spot price you enter. Real-world prices differ: scrap buyers pay a percentage below spot to cover refining, while branded jewelry and rare coins often command a premium above melt. Use this number as the baseline metal worth, then judge any offer against it.
Frequently asked questions
How do I calculate the value of gold?+
Convert the weight to troy ounces, multiply by the purity (karat divided by 24) to get the pure gold content, then multiply by the spot price per troy ounce. For example, 10 grams of 18K gold is 0.3215 troy oz × 0.75 = 0.2411 pure troy oz, worth that amount times the current spot price.
What does karat mean for gold value?+
Karat measures purity out of 24 parts. 24K is essentially pure gold, 22K is 91.6% pure, 18K is 75%, 14K is 58.3% and 10K is 41.7%. Only the pure gold fraction has melt value, so a 14K item is worth a little over half what the same weight of 24K would be.
What is a troy ounce?+
Precious metals are weighed in troy ounces, which are heavier than the everyday avoirdupois ounce. One troy ounce equals 31.1035 grams, while a standard ounce is 28.35 grams. Gold spot prices are always quoted per troy ounce, so the calculator converts your weight accordingly.
Why is the spot price not filled in automatically?+
Gold spot prices change every few seconds, so a static number would quickly be wrong. Look up the current spot price (per troy ounce in US dollars) and type it in. The calculator then gives an accurate melt value for that exact moment.
Will a dealer pay the calculated value?+
Usually not the full amount. The figure here is the pure melt value at spot. Buyers pay below spot to cover refining and profit, often 70-90% for scrap, while finished jewelry and collectible coins can sell above melt value because of craftsmanship or rarity.