What does Even Money mean in blackjack?

Even money means a 1:1 payout — you win the same amount you staked. The phrase has a specific use in blackjack: when you hold a natural (an Ace plus a ten-value card) and the dealer's up-card is an Ace, the dealer offers to settle your bet immediately at 1:1, rather than risk a push if the dealer also makes blackjack. It feels safe, but it is statistically the worse choice. Worked example: you bet £100 and hold a natural; the dealer shows an Ace. Take even money and you bank £100 for certain. Decline, and the only way you fail to collect 3:2 is if the dealer completes blackjack. Holding one ten-value card yourself, 15 of the 49 unseen cards are ten-values, so the dealer makes blackjack about 30.6% of the time. Your expected return from declining is therefore 0.694 × £150 = about £104, against the £100 guaranteed by even money. This matters because even money is mathematically identical to taking Insurance, which is a negative-EV side bet. Over many hands, routinely accepting it costs you roughly £4 per £100 natural. The common mistake is choosing the certain payout for emotional comfort. Unless you are card counting and the remaining deck is unusually rich in tens, decline even money. See also Blackjack, Insurance, Expected Value and House Edge.