Quote from: iensu on March 08, 2017, 09:52:52 AM

oh, so even if I'd use another client for creating these transactions, that would be the same and it's not fault of blockchain.info

that is correct.
although different wallets may use different ways of suggesting appropriate fee but they usually are in the same range. you can also always use this website for more information: https://bitcoinfees.21.co/

Quote

thanks for enlightening me!

But is there any tool to see the size of the transaction before sending it?

your wallet should do that for you. it automatically makes a guess of transaction size then makes an estimate of current fee and gives you final result to make it easy for the end user.
although they usually have an advance section to show you the size and fee in satoshi/byte
i know electrum allows you to set it with an slider and if you preview the transaction before signing it shows you size of the transaction also.