function calculateGoldValue() {
var weight = parseFloat(document.getElementById('goldWeight').value);
var karat = parseFloat(document.getElementById('goldKarat').value);
var pricePerGram = parseFloat(document.getElementById('marketPrice').value);
var resultArea = document.getElementById('goldResultArea');
if (isNaN(weight) || isNaN(pricePerGram) || weight <= 0 || pricePerGram <= 0) {
alert("Please enter valid positive numbers for weight and price.");
return;
}
// Math: Pure Gold Weight = Total Weight * (Karat / 24)
var purityRatio = karat / 24;
var pureWeight = weight * purityRatio;
// Total Value = Pure Weight * Price Per Gram
var totalValue = pureWeight * pricePerGram;
document.getElementById('pureWeightResult').innerHTML = pureWeight.toFixed(3);
document.getElementById('totalValueResult').innerHTML = totalValue.toLocaleString(undefined, { minimumFractionDigits: 2, maximumFractionDigits: 2 });
resultArea.style.display = 'block';
}
Understanding the Gold Gram Calculator
Calculating the value of gold can be confusing because jewelry is rarely made of 100% pure gold. Our gold calculator per gram helps you determine the actual market value of your gold items based on their weight, purity (karat), and the current live market price. This tool is essential for investors, sellers, and hobbyists who need to know the melt value of gold scrap or jewelry.
How Gold Purity (Karat) Affects Value
Gold is typically mixed with other metals like copper, silver, or zinc to make it durable for jewelry. The "Karat" system measures the ratio of pure gold to other alloys:
24K Gold: This is 99.9% pure gold. It is soft and has a rich yellow color.
22K Gold: Contains 22 parts gold and 2 parts other metals (91.6% purity). Common in high-end investment jewelry.
18K Gold: Contains 18 parts gold and 6 parts other metals (75% purity). This is the standard for fine luxury jewelry.
14K Gold: Contains 14 parts gold and 10 parts other metals (58.3% purity). Very popular in the US for its durability.
The Gold Calculation Formula
The math behind our calculator follows a standard industry formula:
1. Pure Gold Weight = Total Weight (g) × (Karat / 24)
2. Total Value = Pure Gold Weight × Current Price per Gram
Step-by-Step Calculation Example
Let's say you have an 18K gold ring that weighs 12 grams, and the current market price of gold is $65.00 per gram.
Determine Purity: 18K / 24 = 0.75 (or 75%).
Find Pure Gold Weight: 12 grams × 0.75 = 9 grams of pure gold.
Calculate Value: 9 grams × $65.00 = $585.00.
Even though the ring weighs 12 grams, its gold value is based only on the 9 grams of pure gold it contains. The remaining 3 grams are alloy metals which usually hold very little monetary value.
Factors to Consider When Selling
While this calculator provides the "melt value" or market value, keep in mind that if you are selling to a dealer or pawn shop, they will likely offer you 70% to 90% of this value to cover their overhead and profit margins. Conversely, if you are buying finished jewelry, the price will be significantly higher than the calculated gold value due to craftsmanship, branding, and retail markups.