For that use case, a dedicated calculator is probably easier than using an exchange. Paybis has a Bitcoin calculator
https://paybis.com/bitcoin-calculator/ that lets you enter the BTC amount and see the corresponding fiat value. You can find it here: Bitcoin calculator. I like this approach for quick estimates because you can change the amount whenever you want and immediately see the converted figure. Just remember that Bitcoin’s market price changes continuously, so the result is best treated as an estimate at that particular moment. If you’re calculating an actual purchase or sale, the final quote can also include fees or a different execution rate.