The calculation formula is: hashrate per 24h * estimated revenue per 24h.
The estimated revenue can be obtained in Help Center page:
And you can also evaluate it through the calculator in home or the labs page, according to the coin type you mine.
Besides, you can view the “Hot Miner” page, and calculate your mining revenue more specific by considering the miner type, miner price and coin’s network difficulty, etc. https://www.f2pool.com/miners
Tips: The mining difficulty is constantly changing for some coins such as ZEC, ETH, ETC, which will lead to the change of estimated revenue per 24h’s value. Therefore, the calculating result is only for the reference.