Single, accumulator and system bets: how they are calculated

A single bet is one prediction with one stake. An accumulator combines several predictions into one bet: the odds multiply, and every selection has to win. A system bet splits the same selections into several smaller accumulators, so it can still pay when one or two selections lose. The thing all three have in common: every extra selection multiplies the odds and the bookmaker's cut together. This article shows how each type is calculated, with numbers, and which rules on the bet slip matter.

Single bet

A single bet is one outcome and one stake: if the prediction is right, you are paid stake times odds.

EUR 10 on a team at odds of 1.80 returns EUR 18 if the team wins - EUR 8 profit plus the stake back. It is the baseline the other two types are measured against. If odds and stake sizes are new to you, start with our guide to sports betting basics; this article assumes you already bet singles. For choosing a bookmaker in general, see our sports betting hub.

Accumulator

An accumulator is several selections in one bet: the odds are multiplied, and the bet wins only if every selection wins.

Latvian bookmakers call it a combined bet ("kombinētā likme"); you will also see "multi", "parlay" and "express". The arithmetic is simple. Three selections at 1.80, 2.10 and 1.60 give combined odds of 1.80 x 2.10 x 1.60 = 6.05. EUR 10 returns EUR 60.50 if all three win.

The probability multiplies the same way. Four selections that each have a 50% chance of winning give a combined chance of 0.5 x 0.5 x 0.5 x 0.5 = 6.25%, or 1 in 16. One wrong selection loses the whole bet, however good the others were.

If a match in your accumulator is cancelled or postponed, most Latvian bookmakers settle that selection at odds of 1.00 and the rest of the bet stands with the remaining selections. This is written in their rules - for example LVBET's general rules and Laimz's sports rules.

System bet: how it is calculated

A system bet covers every combination of a set size from your selections, and each combination is settled as its own small accumulator.

The notation tells you the size. A "2/3" system takes three selections and makes every possible double from them - 3 doubles. A "2/4" system takes four selections and makes 6 doubles. A "3/4" system takes four selections and makes 4 trebles. A combination wins only if all its selections win; the others lose on their own.

A worked example. A 2/3 system with EUR 1 on each combination (EUR 3 in total), selections at odds of 2.00, 1.80 and 1.50. The three doubles are 2.00 x 1.80 = 3.60, 2.00 x 1.50 = 3.00 and 1.80 x 1.50 = 2.70.

• All three win: every double pays - 3.60 + 3.00 + 2.70 = EUR 9.30 back on EUR 3.
• The 1.50 selection loses: only the 2.00 x 1.80 double pays - EUR 3.60 back, EUR 0.60 profit.
• The 1.80 selection loses: only 2.00 x 1.50 pays - EUR 3.00 back, you break even.
• The 2.00 selection loses: only 1.80 x 1.50 pays - EUR 2.70 back, a loss of EUR 0.30, although two of your three selections won.

For comparison, the same EUR 3 as a straight treble would return 3 x 5.40 = EUR 16.20 if all three won, and nothing if any one lost. A system bet trades the top payout for a cushion - and, as the last line shows, the cushion does not always cover the stake.

Stake per combination or total stake

Before you place a system bet, check what the stake field means: some bookmakers charge it per combination, others split it across all combinations.

This is where the same bet can cost six times more or six times less than you intended. Optibet's help page works an example with four events: EUR 1 on the doubles (6 combinations) plus EUR 1 on the trebles (4 combinations) costs EUR 10 in total, because the stake is per combination. OlyBet's rules do the opposite: EUR 2 on a 2/4 system is split across its 6 combinations, about EUR 0.33 each. In OlyBet's own example, with odds of 1.5, 1.4, 1.3 and 1.8, the bet returns EUR 4.48 if all four selections win.

Neither convention is wrong. The risk is switching between bookmakers and assuming the field means the same thing. The bet slip shows the total stake before you confirm - read that number, not the one you typed.

What each extra selection costs

Each selection carries the bookmaker's margin, and in an accumulator those margins multiply, so the bookmaker's edge grows with every selection you add.

The table below assumes two-way markets priced at 1.90 on both sides, where a fair price would be 2.00 - so every selection pays 95% of fair value. That is a typical margin, used here as an example.

• 1 selection: the bookmaker's edge is 5.0%
• 2 selections: 9.75%
• 3 selections: 14.3%
• 4 selections: 18.5%
• 5 selections: 22.6%
• 8 selections: 33.7%
• 10 selections: 40.1%

A four-selection accumulator at 1.90 each pays 13.03, against a fair 16.00 - almost a fifth of fair value is gone before a ball is kicked. This is the arithmetic behind the line in our beginners' guide that accumulators are the bookmaker's favourite product. Big odds are not a sign of value; they are a sign that many margins have been multiplied.

The rules nobody reads

Every bookmaker publishes limits and settlement rules for combined bets, and a few of them change what you can win.

• Cancelled selection: settled at odds of 1.00, the rest of the bet stands (Laimz, LVBET, OlyBet).
• Number of selections: Laimz allows up to 20 events in one combined bet.
• Maximum odds: Laimz caps the combined odds of one bet at 5000.
• Maximum win: LVBET and OlyBet cap the payout at EUR 100,000 per bet.
• Linked selections: you cannot combine outcomes that affect each other - for example, a team to win and the same team to score first - in one ordinary combined bet. Bookmakers that allow this sell it as a separate product, usually called a bet builder, priced for the link.

Some bookmakers also add a boost to combined bets with enough selections, or refund a combined bet that loses by one selection. These are operator mechanics with their own conditions - minimum odds per selection, a minimum number of selections - so read those conditions before counting on them.

If you see "Trixie" or "Yankee"

UK-style names describe full-cover system bets. No Latvian-licensed bookmaker uses them, but foreign sites do.

• Trixie: 3 selections, 4 bets (3 doubles + 1 treble) - a 2/3 and a 3/3 together.
• Patent: 3 selections, 7 bets (a trixie plus 3 singles).
• Yankee: 4 selections, 11 bets (6 doubles, 4 trebles, 1 fourfold).
• Lucky 15: 4 selections, 15 bets (a yankee plus 4 singles).
• Canadian (Super Yankee): 5 selections, 26 bets.
• Heinz: 6 selections, 57 bets.

The names and compositions are standard; Betfair's bet-type guide lists them all. The multiplying stake matters even more here: EUR 1 on a Heinz is EUR 57. Foreign bookmakers are covered on our offshore sportsbooks page.

Where to bet

Among Latvian-licensed bookmakers, Laimz and LVBet both offer combined and system bets, with the limits described above in their published rules. Betrepublic is an offshore sportsbook - check how its bet slip treats the stake before your first system bet. Winnings may be taxable; our article on tax on gambling winnings explains when.

Combined bets are where losses grow fastest on the sportsbook side. Set a budget before you build a bet slip, and stop when it is spent. Our responsible gambling page lists the tools that help, including Latvia's self-exclusion register. Betting is for adults aged 18 and over.