Most cryptocurrency wallets and exchanges set optimal fees for your transfers. To calculate fees, use a third-party service https://bitcoinfees.earn.com The above service calculates the recommended commissions based on historical data for the last hour of work and makes an assumption about the actual commissions at the current moment. Sometimes there are circumstances when the state of the network changes dramatically and the historical data is very different from the current one. In such cases, the specified commission may not be enough to get a quick confirmation, i.e. Your transaction will not be accepted into the next block as intended. Accordingly, confirmation may be delayed until the next blocks, it will take longer than expected. Commission information is for guidance only!