Real-time currency conversion for major fiat currencies like USD, plus popular cryptocurrencies like BTC and ETH — rates refresh automatically each time you open the page.
This tool supports 10 fiat currencies (TWD, USD, JPY, EUR, CNY, HKD, GBP, KRW, AUD, CAD) and 16 major cryptocurrencies (BTC, ETH, USDT, USDC, BNB, SOL, XRP, DOGE, ADA, TRX, TON, DOT, LTC, SHIB, AVAX, LINK). These two groups come from two entirely separate external APIs: fiat rates are fetched from open.er-api.com (USD-based), while crypto prices come from CoinGecko's live pricing API (also priced in USD). Behind the scenes, the tool merges both datasets into a single USD-anchored rate table, so when you convert between a fiat currency and a crypto asset — say, BTC to TWD — it's effectively doing a two-step conversion (BTC → USD → TWD) in one calculation. That's also why crypto conversions display up to 8 decimal places: a single Bitcoin is worth tens of thousands of dollars, so converting it into smaller-denomination currencies needs finer precision to stay accurate.
Many converters give the impression that rates update continuously, but in reality most free tools — this one included — fetch data once, when the page loads, and then hold it fixed until you reload. Nothing updates automatically in the background, even if the tab stays open for hours. This matters little for fiat pairs, which rarely move much within a day, but it matters a lot for crypto: a 5–10% swing in Bitcoin or Ethereum within a single day is not unusual. If you're making an actual trading decision, always check your exchange's live quote rather than relying on a snapshot this tool fetched minutes or hours ago.
Suppose the page fetched 1 BTC = 65,000 USD and 1 USD = 32 TWD. The conversion happens in two steps: first, 0.5 BTC × 65,000 USD = 32,500 USD; second, 32,500 USD × 32 = 1,040,000 TWD. Internally, the tool actually does this in one pass using its unified rate table — it converts the input amount to a USD-equivalent value (0.5 ÷ (1/65000) = 32,500 USD), then multiplies by the target currency's USD rate (32,500 × 32 = 1,040,000) — mathematically identical, just without you doing the two steps by hand. Alongside the result, the tool also shows BTC's 24-hour price change (e.g. "📈 BTC 24h change: +3.2%"), also sourced from CoinGecko, so you get a quick read on recent momentum while converting.
This tool depends entirely on external APIs to function. If open.er-api.com — the fiat rate source — times out (the tool enforces a 10-second timeout) or returns malformed data, the whole converter fails and shows an error message. But if only the CoinGecko crypto request fails, fiat-to-fiat conversion still works fine; the crypto currencies simply don't appear in the dropdown. This is a deliberate fallback design, so one data source going down doesn't take down the other.
No, it's not live. Rates are fetched exactly once, when you open or reload the page, and then stay fixed — there's no background updating. To see the latest rates, just reload the page and it fetches fresh data.
The actual conversion math runs entirely in your browser — the amount you type is never sent anywhere. That said, to be fully transparent: this page does make outbound network requests to two third-party APIs on load (open.er-api.com for fiat rates, CoinGecko for crypto prices) to fetch current rate data. That's different from the loan and retirement calculators, which are 100% local with zero network calls. Those requests only download a rate table — they never transmit any amount or personal data you entered.
Crypto prices come from a separate API (CoinGecko). If that request fails, times out, or gets rate-limited, the tool silently skips crypto data without breaking fiat-to-fiat conversion — you'll just see a "Fiat Currencies" group in the dropdown with no "Cryptocurrencies" group. This usually resolves itself if you reload the page or try again shortly after.
This is intentional: when the converted result's absolute value is less than 1 (e.g. converting into a very small unit, or a low-priced token), it displays up to 8 decimal places to preserve precision; otherwise it displays 2 decimal places, matching normal currency conventions. This only affects the displayed rounding — the underlying calculation always uses full precision.
It's a rolling 24-hour price change, also sourced from CoinGecko, and only shown for cryptocurrencies (fiat pairs don't display a change figure). It reflects the 24 hours ending at the moment the data was fetched, not a fixed daily close — treat it as a reference only and check your exchange for the live figure before trading.