31 Betting System: How to Read the Chart and Cap Losses

The 31 system is a betting system in which two wins in a row within one cycle are enough to lock in a profit for that cycle. It takes its name from the fact that the total amount bet in a single cycle comes to no more than 31 units.

Its drawbacks are that you need to prepare a chart showing the betting sequence in advance, and that adjusting your bet according to a fixed set of rules takes some effort.

What You Will Learn

• With the 31 system, two wins in a row within a cycle put you in profit at that point.
• Each cycle has a clear end point, so you do not have to decide for yourself when to stop.
• It is used on even-money bets that pay 1 to 1 (a $10 bet wins $10), and the loss in one cycle is capped at 31 units.

This article takes about 15 minutes to read.

What Kind of Betting System Is the 31 System?

The 31 system is one of the betting systems used in casinos. It is played on even-money bets in games such as roulette and baccarat, where a win pays 1 to 1 and a loss costs your stake, and you raise your bet according to a chart as you win or lose.

The Martingale system, for example, also raises the bet after a loss. A single win always puts you ahead, but nine losses in a row cost a total of 511 units. If your first bet is $1, nine straight losses mean a loss of $511.

With the 31 system, by contrast, the loss is limited to $31 even if all nine bets in a cycle lose. The system suits players who want to set a cap on how much they can lose per cycle in advance.

Casino Games That Work Well with the 31 System

The 31 system can be used on bets that pay 1 to 1, where a $10 bet wins $10 and you get $20 back in total. For this reason, it is usually played on bets that win about 50% of the time, such as the following.

• Red/black, odd/even and high/low in roulette
• The Player bet in baccarat
• Big/Small in Sic Bo

In many money wheel games, even the segments that pay 1 to 1 come up far less than 50% of the time, so these games do not fit the assumptions of the 31 system. We also do not recommend using it in blackjack, because actions such as doubling down and splitting can require additional bets.

Under standard rules, a commission is deducted from winning Banker bets in baccarat, so the bet pays 0.95 to 1 (19 to 20) and a $10 bet wins $9.50 (returning $19.50 in total), which no longer matches the 31 system chart. In no-commission baccarat, a Banker win on 6 usually pays half (1 to 2), which also breaks the assumption that a win pays 1 to 1. If you use the system in baccarat, choose the Player bet.

How to Bet with the 31 System: Step by Step

The 31 system is played in cycles of up to nine rounds. A cycle ends in success as soon as you win twice in a row, but keep in mind that every cycle ends after nine rounds at most, whether it succeeds or fails.

It helps to picture the sequence 1, 1, 1, 2, 2, 4, 4, 8, 8. This is the order of your bets and shows how much to bet after a loss or a win. Adding up every number in the sequence gives 1 + 1 + 1 + 2 + 2 + 4 + 4 + 8 + 8 = 31, which is where the name “31 system” comes from.

Suppose your first bet is $1. Then:

• If you lose → bet the next amount in the sequence, $1
• If you win → skip ahead to the start of the next group in the sequence and bet $2
• If you win twice in a row → the cycle succeeds. Reset your bet and start the next cycle

That is the basic process.

Step (1): Choose a Game and Your Unit Size

First, decide how much one unit is worth. The 31 system uses up to 31 units per cycle, so you need a bankroll of at least 31 units. If you bring exactly 31 units, however, a single failed cycle will wipe out your bankroll. As a guideline, keep one unit to about 0.5% of your total bankroll (so the maximum loss in one cycle is about 16% of the bankroll), a level at which you can keep playing even after several failed cycles in a row. In the examples below, one unit equals $1.

Next, choose a game that meets the conditions described above.

Step (2): Prepare the Chart and Follow It

Prepare the chart shown above. It sets out the order in which you bet with the 31 system. In text form, it looks like this.

You bet your way through the chart starting from the top left.

For the first bet, the number in the top-left cell (A-(1)) is 1, so you bet $1. The number stands for one unit, so if you set one unit at $10, bet $10.

After a loss, move one cell to the right for the next bet (A-(2)). This cell is also 1, so you bet $1. When there is no number to the right, such as after a loss on A-(3), move to the leftmost cell of the next row. In the event of a tie, repeat the same bet on the next round.

After a win, move to the leftmost cell of the next row (B-(1)). That cell shows 2, so your next bet is $2. Row D, the bottom row, has no row below it, so after a win on D-(1) you simply bet on D-(2).

Step (3): Two Wins in a Row Mean Success

The cycle succeeds as soon as you win twice in a row. Reset your bet and start again from A-(1).

Step (4): No Two Wins in a Row by the End Means Failure

If you never manage two wins in a row and lose on D-(2), the 31 system has failed for that cycle. Even if you win on D-(2), the cycle still ends as a failure unless that win completes two in a row. In either case, reset your bet and start again from A-(1).

31 System Simulation Results

In this example, we keep betting on red in roulette with the 31 system, and the results run loss, win, loss, loss, win, win.

The results were three wins and three losses, yet the cycle ended with a profit of $8, a fairly large win for a betting system that starts with a $1 bet.

Unlike the Martingale system or the Cocomo system, however, the 31 system is not designed to recover all earlier losses with a single win, so you can win the last round of a cycle and still be behind overall. Choose your unit size with care.

What the 31 System Can and Cannot Change

Like any betting system, the 31 system can change only the size of the swings in your results (the variance) and the shape of the distribution of wins and losses. It does not change the game’s house edge, expected value or return to player (RTP) in any way.

The 31 system simply reshapes the result of each cycle so that small profits are more common and a failed cycle costs up to 31 units. Over the long run, its expected value is the same as flat betting, in which the bet never changes. If you bet on red, the 2.70% house edge of European roulette applies whether you use the 31 system or not, and the same is true of the 1.24% house edge on the Player bet in baccarat.

With a maximum bet of 8 units per cycle, the 31 system is less likely than many systems to reach the table limit, but the table limit and your bankroll are still finite. If you set a large unit, the 8 units in row D can exceed the table limit, and you will not be able to finish the chart. Before you decide on a unit size, check that 8 units fit within the table limit.

As noted above, the maximum loss in one cycle is 31 units, but the failure rate per cycle is too high to ignore, so base your play on a bankroll you can comfortably afford.

Pros and Cons of the 31 System

Two Wins in a Row Are Enough to Secure a Profit

Because two wins in a row at any point within a cycle of up to nine rounds secure a profit, a relatively high share of cycles end in profit.

Even if you lose the first seven rounds, the cycle ends with a profit as long as the last two rounds are both wins. Success depends not on how many rounds you win but on whether two consecutive wins appear somewhere in the cycle, so a cycle can end in profit even with only a few wins. The system does not, however, raise your chance of winning any individual round.

The Maximum Loss per Cycle Is 31 Units

As the name suggests, even if you lose all nine rounds in a cycle, you lose no more than 31 units.

That 31-unit loss is the maximum, reached only after nine straight losses, not the average loss when a cycle fails. Nine straight losses on red in roulette happen only about 0.25% of the time (roughly once in 400 cycles), but working through the chart without ever winning twice in a row, and failing as a result, happens far more often. Play enough cycles and you will eventually lose the full 31 units in one of them.

A larger unit also means a larger maximum loss. With one unit at $10, for example, the maximum loss per cycle is $310, so be careful not to set your unit too high.

Clear Profit-Taking and Stop-Loss Points

The system tells you to take your profit after two wins in a row and to accept the loss if you have not won twice in a row by the ninth round, so you do not have to decide for yourself when to take profits or cut losses, and you never have to agonize over when to stop. Setting a stop-loss limit does not change the expected value, though. It is a money management rule that caps how much you can lose in one session.

You Lose Money Unless You Win Twice in a Row

An obvious drawback of the 31 system is that a single win is not enough to make a profit.

The 31 system shows a profit only after consecutive wins. Losses naturally mount during a losing streak, but a cycle also fails if, for example, wins and losses alternate (win, loss, win, loss) and you reach the end of the chart without ever winning twice in a row.

The loss on a failed cycle is capped at 31 units ($31 at $1 per unit), but a cap on losses is not the same as having no losses. If cycle after cycle passes without two wins in a row, your bankroll keeps shrinking, 31 units at a time.

Betting Mistakes Can Cost You the Profit

This is not unique to the 31 system, but if you bet incorrectly, the system may fail to produce a profit.

The 31 system in particular calls for different actions after a win, two wins in a row, a loss and a tie, so mistakes are common: failing to reset after two wins in a row and betting the same amount on the next round, or moving down a row after a loss.

Until you are comfortable with the system, we recommend practicing on RNG roulette or RNG baccarat, which have no time limit for placing bets, and moving on to live dealer games once you know the 31 system chart by heart.

Variations on the 31 System

The 31 system is a flexible betting system, and players use many variations of it. One of them works as follows.

• Use the same chart as the 31 system described above
• After a win, move one cell to the right, just as after a loss, instead of moving down a row (in other words, the bet stays the same)

Put simply, you move one cell to the right on the chart whether you win or lose.

Opinions differ on the correct way to use the 31 system, and some players say this version is the original 31 system.

Simulation Results for the Modified Version

The cycle ended in profit thanks to two wins in a row at the end. Under the standard 31 system, however, a win at A-(1) skips A-(2) and A-(3), so the same sequence of results would never have produced two wins in a row, and the cycle would have failed.

Pros and Cons of the Modified Version

Pros

• Two wins in a row still guarantee a profit

  Even with this change, a cycle is in profit as soon as you win twice in a row, and the cap on losses is unchanged.

• More chances to win twice in a row within a cycle

  The success condition is still two wins in a row, but in the standard 31 system each win reduces the number of rounds left, while the modified version lets you bet up to nine times unless the cycle succeeds first. This gives you more chances to win twice in a row within a cycle. What increases, however, is only the share of cycles that succeed. Each success brings a smaller profit, so the overall expected value is the same as in the standard version.

• Easier for beginners

  In the standard version, you move differently after a win and after a loss. In the modified version, the sequence of bets is the same whether you win or lose, so there is less room for confusion.

Cons

• Two wins in a row bring only a small profit

  Because the bet rises more gradually, you get more chances to win twice in a row within a cycle, but the profit per cycle is smaller. In the modified version, two wins in a row after a run of losses yield a fixed profit of 1 unit (2 units if the first two rounds are both wins). In the standard version, by contrast, the profit grows the further down the chart the wins come. Any single wins earlier in the cycle add to the profit, which is why the simulation above ends at +$7.

• Each cycle takes longer

  The standard version moves down a row after each win, while the modified version continues for up to nine rounds unless it succeeds, so each cycle takes longer to complete.

Other variations exist as well, such as cutting your losses after a loss at D-(1) instead of betting on D-(2). Every variation changes only where a cycle ends, so try the one that suits your preference.

Comparison with Related Betting Systems

Paroli System

The Paroli system (also called the reverse Martingale) is a betting system in which you double your bet after each win. The 31 system also doubles the bet after a win, but while the 31 system ends a cycle after two wins in a row, the Paroli system places no limit on when you take your profit.

You can lock in your profit after five wins in a row or keep going to ten. The longer you let the streak run, the lower your chance of success, but five wins in a row return 32 times your initial stake (a profit of 31 times the stake), and ten wins in a row return 1,024 times (a profit of 1,023 times). A single loss along the way wipes out everything you have built up, however, so with this system you have to decide for yourself where to stop.

Oscar’s Grind

Oscar’s Grind is similar to the 31 system in that consecutive wins can produce a profit even after a run of losses. You keep the same bet while you are losing and raise it by one unit each time you win.

For example, if you start at $1, you keep betting $1 while you are losing, and each time you win while still behind, you raise the bet by $1 (but never so far that the next win would take your profit above one unit). The cycle ends once you are ahead by a total of one unit. This method also depends on consecutive wins, so it is a betting system that takes patience.

D’Alembert System

The D’Alembert system (also called the pyramid system) is a betting system for players who want to change their bets gradually. You set an initial bet, add one unit after a loss and subtract one unit after a win, which keeps the swings in your results small.

Cycles tend to run long, but sudden large swings in your bankroll are less likely, which makes it a system suited to steady, unhurried play.

Summary: The 31 System Is a Money Management Method That Caps Losses per Cycle

The 31 system is a betting system for players who want to cap their losses per cycle. It can be used on bets that pay 1 to 1 (a $10 bet wins $10), such as the Player bet in baccarat or red/black in roulette.

You bet according to a chart that tells you what to do after each win or loss. The system gives each cycle a clear end point: it succeeds once you win twice in a row and fails if you reach the end of the chart without doing so. As a result, you do not have to decide for yourself when to stop.

Even if you lose all nine rounds in a cycle, your loss is limited to 31 units. This only narrows the swings within a cycle, however; it does not change the house edge or the expected value. Treat the system as a money management framework, and choose a unit size your bankroll can comfortably support.