function calculatePlatinumValue() {
var marketPrice = parseFloat(document.getElementById('pt_market_price').value);
var weight = parseFloat(document.getElementById('pt_weight').value);
var purityRaw = parseFloat(document.getElementById('pt_purity').value);
var makingPercent = parseFloat(document.getElementById('pt_making_percent').value);
var taxPercent = parseFloat(document.getElementById('pt_tax').value);
// Validation
if (isNaN(marketPrice) || marketPrice <= 0) {
alert("Please enter a valid current market price per gram.");
return;
}
if (isNaN(weight) || weight <= 0) {
alert("Please enter a valid weight in grams.");
return;
}
if (isNaN(makingPercent)) makingPercent = 0;
if (isNaN(taxPercent)) taxPercent = 0;
// Purity Calculation: Fineness (e.g., 950) divided by 1000 gives the decimal percentage
var purityFactor = purityRaw / 1000;
// 1. Calculate Base Metal Value
// Formula: Market Price * Weight * Purity Factor
var baseMetalValue = marketPrice * weight * purityFactor;
// 2. Calculate Making Charges
// Usually calculated on the base price of the gold/platinum or a fixed rate per gram.
// Here we use percentage of base value as requested in common jewelry scenarios.
var makingCharges = baseMetalValue * (makingPercent / 100);
// 3. Subtotal before Tax
var subTotal = baseMetalValue + makingCharges;
// 4. Calculate Tax
var taxAmount = subTotal * (taxPercent / 100);
// 5. Total
var totalValue = subTotal + taxAmount;
// Display Results
document.getElementById('display_metal_val').innerText = baseMetalValue.toFixed(2);
document.getElementById('display_making_val').innerText = makingCharges.toFixed(2);
document.getElementById('display_tax_val').innerText = taxAmount.toFixed(2);
document.getElementById('display_total_val').innerText = totalValue.toFixed(2);
document.getElementById('pt_result_container').style.display = 'block';
}
How to Calculate Platinum Rate: A Comprehensive Guide
Calculating the true value of platinum jewelry or scrap metal involves more than just weighing the item. Platinum is a dense, precious metal often used in high-end jewelry, and its price calculation differs slightly from gold due to different standard purity markings and making charges. Whether you are buying an engagement ring or selling old platinum scrap, understanding the formula is essential for getting a fair deal.
The Basic Formula
The core formula to calculate the intrinsic value of platinum is relatively straightforward:
Platinum Value = (Weight in Grams) × (Current Market Price per Gram) × (Purity / 1000)
However, the retail price (what you pay at a store) includes additional costs like making charges and taxes.
Total Retail Price = Platinum Value + Making Charges + Taxes (VAT/GST)
Understanding the Variables
1. Platinum Purity (Fineness)
Unlike gold, which is measured in Karats (e.g., 24k, 18k), platinum purity is usually measured in parts per thousand. This is known as "fineness." The most common stamps you will see are:
Pt950 (95% Pure): The standard for high-quality jewelry. It contains 950 parts platinum and 50 parts other alloys (often ruthenium or cobalt).
Pt900 (90% Pure): Common in older jewelry or specific casting applications.
Pt999 (99.9% Pure): Used mostly for investment bars and coins.
Pt850 (85% Pure): The minimum standard often accepted as "platinum" in chain jewelry.
2. Current Market Price
Platinum is a traded commodity, and its price fluctuates daily. When using the calculator above, ensure you find the "Spot Price" of platinum per gram. Note that the spot price is always for 99.9% pure platinum. This is why the purity factor in the calculation is so critical.
3. Making Charges
Platinum is denser and has a higher melting point than gold, making it more difficult to work with. Consequently, making charges (labor costs) for platinum jewelry are typically higher than for gold. These are usually expressed as a percentage of the metal value (ranging from 15% to 30%) or a flat rate per gram.
Calculation Example
Let's say you want to buy a Pt950 Platinum Ring weighing 8 grams.
Current Market Price: $30.00 per gram (Hypothetical)
Weight: 8 grams
Purity: 950 (95%)
Making Charges: 20%
Tax: 5%
Step 1: Calculate Metal Value
$30.00 × 8 grams × 0.95 = $228.00
Step 2: Add Making Charges
$228.00 × 20% = $45.60
Step 3: Subtotal
$228.00 + $45.60 = $273.60
Step 4: Add Tax
$273.60 × 5% = $13.68
Final Price: $287.28
Why is Platinum Density Important?
Platinum is significantly denser than gold. If you have two identical rings—one made of 18k gold and one of Pt950 platinum—the platinum ring will weigh approximately 40% more. Since precious metals are sold by weight, the platinum ring will cost more simply because it contains more grams of metal, even if the price per gram between gold and platinum is similar.
Tips for Buyers and Sellers
Check the Hallmark: Always look for the "Pt" or "PLAT" stamp followed by the number (950, 900) inside the jewelry.
Separate Stones: If selling scrap platinum, remember that gem weight should be deducted. The calculator applies to the metal weight only.
Negotiate Making Charges: While the metal rate is fixed by the market, making charges are often negotiable at jewelry stores.