Whether you're eyeing an old chain in a drawer, checking what your Bitcoin is worth today, or just want to convert USD to EUR before a trip, the math behind "what's this worth in dollars" is more consistent than it looks. Here's how live currency rates, live crypto prices, and manual gold/silver spot-price math actually work — with a worked example you can follow along with.
Converting currency at a live rate
Short answerEnter an amount, pick a source and target currency, and the conversion uses a live exchange rate fetched from Frankfurter (which republishes European Central Bank reference rates), so the number you see reflects the current market, not a rate from last week.
Exchange rates move constantly during the trading day as banks, funds, and travelers buy and sell currency. A converter that hard-codes a rate becomes wrong within hours. That's why a currency calculator is only useful if it pulls live data — in this case, USD as the base against nine other major currencies (EUR, GBP, CAD, AUD, JPY, CHF, CNY, MXN, INR).
For example, if you're planning a trip and want to know what $500 is worth in euros, you'd enter 500, set USD as the source and EUR as the target, and read off both the converted amount and the exact rate used — so you know precisely what number you're working from, not just a rounded headline figure.
Good to know: a "swap" button lets you flip source and target instantly (useful for going EUR → USD instead of USD → EUR), and a refresh button re-fetches the latest rate on demand rather than relying on a cached page load.
Checking live Bitcoin & Ethereum prices
Short answerLive prices for Bitcoin, Ethereum, Solana, and Dogecoin are fetched from CoinGecko's public market-data API, showing the current US-dollar price and the 24-hour percentage change for each coin, alongside a converter for coin-to-coin or coin-to-USD amounts.
Crypto prices are far more volatile than currency exchange rates — a coin's dollar price can move several percentage points within an hour. A useful crypto reference needs to be live at the moment you check it, not a static snapshot.
Example: say you want to know what 0.75 ETH is worth in dollars, or what 2 SOL would get you in ETH. Instead of doing the cross-rate math by hand (looking up both coins' USD prices and dividing), a converter that fetches both live prices and computes the cross rate for you saves a step and avoids arithmetic mistakes — particularly useful when comparing small holdings across several coins at once.
Calculating gold value from spot price
Short answerGold value = weight in grams × (spot price ÷ 31.1035) × purity fraction, where 31.1035 grams is one troy ounce and the purity fraction depends on karat: 24K = 0.999, 22K = 0.9167, 18K = 0.75, 14K = 0.5833, 10K = 0.4167.
Unlike currency and crypto, there's no free, reliable, no-signup live feed for gold and silver spot prices. Rather than showing a stale or made-up number, the honest approach is to ask you to check today's spot price yourself — from your bank, a bullion dealer, or a market-data site you trust — and enter it manually. From that one number, all the gram-to-troy-ounce and karat-purity math can be done instantly.
Worked example (hypothetical figures, not a live quote): suppose today's gold spot price is $2,400 per troy ounce. One gram of pure (24K) gold would be worth about 2400 ÷ 31.1035 ≈ $77.16. If you have a 14K bracelet weighing 10 grams, its melt value would be roughly 10 × 77.16 × 0.5833 ≈ $450 — well below the "full gold" price, because a 14K item is only about 58.3% gold by weight.
Example only — illustrative, at a hypothetical $2,400/oz gold spot price
| Karat | Purity | Value per gram | Value per 10g |
|---|
| 24K | 0.999 | $77.08 | $770.80 |
| 22K | 0.9167 | $70.74 | $707.40 |
| 18K | 0.750 | $57.87 | $578.70 |
| 14K | 0.5833 | $45.00 | $450.00 |
| 10K | 0.4167 | $32.15 | $321.50 |
The same math applies to silver: swap the gold spot price for the silver spot price, and use silver purities instead — fine silver (.999), sterling silver (.925, the common purity for jewelry and flatware), or coin silver (.900).
Gold coin melt value (Krugerrand, Eagle, and more)
Short answerCoin melt value = gross weight in grams × purity fraction × (gold spot price ÷ 31.1035) — and named bullion coins differ in both gross weight and purity, so the same "1 oz" label doesn't always mean the same gross weight.
This trips people up: a 1 oz American Eagle and 1 oz Krugerrand are both 22K (.9167 purity) with a gross weight around 33.93 grams — heavier than a pure ounce, because the "1 oz" refers to the pure gold content, with the rest made up of alloy metals for durability. A 1 oz Canadian Maple Leaf or Britannia, by contrast, is .9999 fine and weighs closer to 31.10 grams, since there's almost no alloy to add. A British Sovereign is a different case again — smaller, 22K, at about 7.988 grams gross.
Because of these differences, a coin melt-value calculator needs each coin's actual gross weight and purity built in, rather than assuming every "1 oz" coin weighs the same. Pick the coin, enter a quantity, and the pure-gold content and dollar melt value are computed from whatever spot price you entered above.
Frequently asked questions
How do you calculate the value of gold from its spot price?
Gold value = weight in grams x (spot price / 31.1035) x purity fraction, where 31.1035 grams is one troy ounce and the purity fraction reflects the karat (24K = 0.999, 22K = 0.9167, 18K = 0.75, 14K = 0.5833, 10K = 0.4167). For example, if gold spot is $2,400 per ounce, one gram of 24K gold is worth about 2400 / 31.1035 = $77.16, and 10 grams of 14K gold would be worth about 10 x 77.16 x 0.5833 = $450.
Why do I have to enter the gold and silver spot price myself?
There is no free, reliable, no-signup API that provides live gold and silver spot prices, unlike currency and crypto markets. Rather than showing a stale or inaccurate number, the tool asks you to check today's spot price from a source you trust (your bank, a bullion dealer, or a market-data site) and enter it manually. It then handles all the gram, troy-ounce, and karat math for you.
How do you calculate the melt value of a gold coin like a Krugerrand or American Eagle?
Melt value = coin's gross weight in grams x purity fraction x (gold spot price / 31.1035). A 1 oz American Eagle and 1 oz Krugerrand are 22K (.9167 purity) with a gross weight around 33.93 grams, so each contains exactly 1 troy ounce of pure gold, while a 1 oz Canadian Maple Leaf or Britannia is .9999 fine and weighs about 31.10 grams. A British Sovereign is smaller and 22K, at about 7.988 grams gross.
Are the currency and crypto prices live, and is the gold price live too?
Currency conversion uses Frankfurter, which republishes European Central Bank reference exchange rates, and cryptocurrency prices come from CoinGecko's public market-data API — both fetched live in your browser. Gold and silver spot prices are the one exception: since no free, reliable live metals feed exists, you enter today's spot price yourself and the tool does the gram/troy-ounce/karat math instantly.
Is this gold and currency calculator financial advice?
No. It performs standard currency, crypto, and precious-metal math for informational purposes only. Exchange rates, crypto prices, and metal values shown can differ from what you actually get from a bank, exchange, or dealer once fees and spreads are included. Always confirm current rates with your financial institution before making a transaction.
Related guides
Methodology note: currency figures use live rates from Frankfurter (ECB reference rates) and crypto prices from CoinGecko's public API, both fetched at the time of viewing. Gold and silver examples in this article use a hypothetical $2,400/oz spot price purely to illustrate the karat math — always check a live spot price before using these figures for any real transaction. This article is for informational purposes only and is not financial advice.