Blackjack Side Bets: What Each One Pays and How Much It Costs

We calculated each figure ourselves from the number of cards in a six-deck shoe and checked it against the published tables.^{1 (source)2 (source)} The worked examples are in the sections below. Pay tables differ between casinos and between online games, so the help screen or the felt is what tells you which row applies.

Side bets are popular because they pay on a single event and sometimes pay big, and because they add something to watch while the main hand is dealt. None of that changes the price. A £5 side bet on every hand costs more, on average, than the £10 main bet next to it.

The calculation is short. Whatever your first card is, a six-deck shoe has 311 cards left. Five of them are the same rank and suit (the other five copies across six decks), six are the same rank in the other suit of that colour, and twelve are the same rank in the two suits of the other colour.

Multiply each chance by its payout: 25 × 5 + 12 × 6 + 6 × 12 = 269 units won for every 311 hands. The 288 no-pair hands lose one unit each. The net is −19 units per 311 hands, a house edge of 6.11%. The same method gives 5.79% for the 30/10/5 table and 9.97% for 25/12/5, matching the published figures.^{1 (source)}

More decks make pairs slightly more likely, so an eight-deck game is a little cheaper: 4.10% on the 25/12/6 table.^{1 (source)} A two-deck game is far dearer, which is why the bet is rarely found there.

Out of every 1,000 three-card hands dealt from a six-deck shoe, about 97 make one of the paying hands. We counted them exactly: there are 5,013,320 ways to take three cards from 312, and 485,096 of them are a flush, straight or three of a kind (straight flushes and suited trips counted once). That is a 9.68% chance of winning. At 9:1 the bet returns 10 × 9.68% = 96.76% of each stake, a house edge of 3.24%.^{2 (source)}

Many games use a tiered table instead, paying 5:1 for a flush and up to 100:1 for suited three of a kind. These look more generous at the top, but the most common winning hand, the flush, pays less, and the overall edge is usually higher. One such table, 100/40/30/10/5, comes out at 3.70% on eight decks; the “Xtreme” 30/20/10/5 table at 13.39% on six.^{2 (source)}

The arithmetic is the same as for any side bet. The insurance wins only if the dealer’s next card is worth ten, and 4 of the 13 ranks are. So the bet wins 2 units with a chance of 4/13 and loses 1 unit with a chance of 9/13: 8/13 − 9/13 = −1/13, a loss of 7.69% per pound insured.

Even money, the offer to take a guaranteed 1:1 on your own blackjack when the dealer shows an Ace, is insurance in another form and carries the same cost. Taking it gives up the 3:2 payout in the hands where the dealer does not have blackjack. The blackjack rules page explains how insurance fits into a round.

With one deck there are no identical cards at all, so a perfect pair is impossible; with six decks there are five more copies of every card. The 25/12/6 Perfect Pairs table goes from 22.33% on two decks to 6.11% on six and 4.10% on eight.^{1 (source)} 21+3 follows the same pattern: 7.26% on two decks, 3.24% on six.^{2 (source)}

The main game moves the other way: fewer decks are slightly better for the player there. That contrast is worth knowing when a table advertises a single-deck game with a side bet attached.

The figures are simple products: stake × house edge. The side bets are half the size of the main bet and still cost three to six times as much per hand. Over an evening of a few hundred hands those small amounts add up, which is the real reason casinos promote them.

A £5 Perfect Pairs bet at 25/12/6 costs about 30.6p on average, against under 3p for the same £5 on the main hand; our house edge guide compares these figures with every other game in the casino.

Looking for a licensed site that shows its side-bet pay tables? Our UK casino comparison lists the licensed UK sites. 18+