The surrender rule makes you give up 50% of your
bet. In the long run, you should only put the play into action when you are dealt two cards that, based on percentages, will lose approximately 75% of the time.
If the dealer's up card is 9 through Ace, always surrender when your first two cards equal fifteen or sixteen.
If the dealer's up card is 10 through Ace, surrender when your first two cards equal four, five, six, or seven. (Exception: Take a hit if one card is an Ace.)
This is a very broad base for surrender moves. There is a lot of controversy among so‑called
Blackjack
experts about surrendering the four through seven hands, but I have found that by throwing in these very weak hands against the dealer's strong cards, losses are reduced.