Please note, these values are loaded from CoinMarketCap when you load the page, and if you leave the page open for too long, the values will be off. You could end up sending the incorrect amount. Please make sure to refresh and get an updated value before sending payment. You can also do the math yourself on CoinMarketCap. Sometimes the calculator errors out, if you see words inside the amount to send, it means the API stopped pulling and you will need to calculate the costs yourself.