What makes a side bet progressive
Most side bets pay fixed multiples of the stake. A progressive jackpot side bet pays at least one prize that changes. Part of each stake, often a small fixed amount, goes into a shared meter, and the meter grows until someone hits the qualifying hand. When that happens the player is paid all or part of the meter, and the meter resets to a seed amount. On a live table the meter is often shared across many tables or players, and in online games it can span a whole network.
The qualifying hand is typically a rare combination built from the first few cards, such as a very specific suited sequence. Tables also pay smaller, fixed prizes for less rare outcomes. Details differ widely, so the actual rules for the game in front of you matter more than anything described in general terms here.
Why the prize grows
The meter has two sources. A seed amount sets the starting figure, and then a slice of every qualifying stake is added. Because the slice typically comes out of the money players wager on the bet, the growth is not free money. It is the same stake being routed to a different pot.
That is the first thing to see in the maths. The portion that goes to the meter is not available to pay the ordinary prizes. So the base pay table of a progressive side bet is usually leaner than that of a comparable non-progressive bet, with part of the expected return pushed into the rare jackpot.
The arithmetic of a jackpot
Think of the expected return in two parts: the ordinary prizes, and the jackpot. The jackpot’s contribution to your average return per unit staked equals the chance of hitting it times its size, in units of your stake.
Here is an invented example. Suppose the jackpot hand occurs once in a million bets, and the meter currently holds 500,000 times the stake. The jackpot adds 500,000 ÷ 1,000,000 = 0.5 units per unit staked, on average. If the ordinary prizes return 0.4 units per unit staked, the total return is 0.9, which leaves an edge of 10%. If the meter held only 200,000 times the stake, the jackpot would add 0.2, and the total would be 0.6, an edge of 40%.
The same bet is therefore worth quite different amounts depending on the meter. To break even, the jackpot would need to supply the difference between the ordinary return and one: with ordinary prizes returning 0.4, the meter would need to hold 600,000 times the stake at a one-in-a-million hit rate, since 0.6 × 1,000,000 = 600,000. The hit rate and pay table here are made up for illustration, and real ones are set by each game.
Why a big meter is not a signal to play
A large meter tempts people to think the bet has turned in their favour. A few cautions apply.
- Even where the arithmetic comes close to break-even, a bet that wins once per million tries leaves almost every player with a long run of losses. The jackpot is real, but the realistic outcome for nearly everyone is losing the stakes.
- Several players can share a pot, or the prize can be split on ties, so the amount you receive may be less than the figure displayed.
- The meter resets after a hit, and the number on the sign is not a reason in itself to place the bet.
- Rules can tie the full jackpot to a particular stake size, so smaller stakes may win only a fraction of the meter.
No figure on a display turns a game with a negative expected value into a sound plan for making money. Results in the short term are uncertain, and the chance of walking away with the jackpot remains tiny.
Volatility
Progressive side bets are about the most volatile wagers in the game. Almost all of the return is delivered through events that happen very rarely, so the standard deviation of your results is large relative to your stake. Ordinary swings in a session can be much bigger than the average cost suggests. For that reason, a short experience with the bet, positive or negative, tells you very little. In a session of a few hundred hands, even a bet with a hit rate of one in a thousand will fail to land more often than not, since the chance of no hit in 300 attempts is about 74%.
Check: (1 − 0.001) raised to the 300th power is about e to the power of −0.3, which is roughly 0.74.
Responsible play
Large prizes can make people stake more than they intended. A sensible approach is to decide beforehand what the bet is worth to you as entertainment and stop there. Avoid chasing losses or increasing side stakes to catch a hit that feels due. A prize that has not landed for a long time is not overdue, and the gamblers fallacy applies to jackpots as much as anything else. If gambling is becoming a concern, local support services can offer free, confidential help.