A big blind is a predetermined amount that the player who’s sitting in the second position to the dealer’s left places before any of the cards are dealt.
As the dealer button moves clockwise with every round, every player must eventually pay the big blind during a poker game.
Big blinds are most often the same amount as the minimum bet you can bet, making a small percentage of your overall stack.
Let’s say that you’re playing at a $5/$10 table, so the small blind is $5, and the big blind is $10. You’re guaranteed to pay $15 for every round the dealer makes around the table, plus the big blind ante, if it’s an ante game.