Your Square payout is smaller than your gross sales because Square deducts its processing fee before it sends you the money. That is the single fact that drives the whole reconciliation: the fee is netted out at the source, so it never shows up as a separate withdrawal on your bank statement — it is simply missing from the deposit. If you book the deposit as your sales figure, you have understated revenue by exactly the fee, and you have no expense line recording what that fee cost you.
The fee is not the only thing sitting between the two numbers. Tips a customer adds on the card reader arrive inside the payout but are owed back to staff, so they are not your income. Refunds you issued reduce the payout, because Square hands the money back to the customer and takes it out of what it transfers to you. And timing pulls the dates apart: a sale rung up on one date can settle into your bank on another, depending on your transfer settings. Each of those is a specific, recordable piece — and when all of them are broken out, the deposit and the sales finally agree. We never quote what Square charges, because Square sets its own pricing and it varies by card type and plan; we read the actual fee Square reported on each batch and record that.