Round Betting Calculator for Boxing: Implied Chance by Round and Group

Using the calculator

The calculator reads a round market the way a bookmaker builds one: as a list of outcomes, exactly one of which will happen if the fight takes place. Start with the Market menu. “Group betting” is the default and lists each boxer to win by KO, TKO or DQ in each block of three rounds, each boxer on points, and the draw. “Exact round” lists every scheduled round for each boxer instead. “Custom outcomes” gives you between 2 and 30 blank rows, each with its own name, for any market the presets do not cover.

Next, set the scheduled rounds. The choice is 12, 10, 8, 6 or 4, and the board rebuilds to match. Groups are cut in threes and the last one is shortened, so a ten-round fight has rounds 1–⁠3, 4–⁠6, 7–⁠9 and round 10, and an eight-round fight ends with rounds 7–⁠8. Group betting is not offered below eight rounds, because two groups add little to the fight result. If you have already typed prices, the tool asks before it clears them.

The two corner names are optional and only change the labels; they default to Red and Blue, and nothing is pre-filled with a real boxer. Then type a price into each row. The boxes accept fractions such as 9/2 or 9-2, the word Evs, or decimals such as 5.50. A price the tool cannot read is marked with “Use a price like 9/2, Evs or 5.50.”, and a decimal of 1.00 or less is refused, because it would mean no return at all. Neither kind of error enters the total. The Example prices button reloads the market shown on this page.

The last control is the checkbox This is the full market. It matters because the margin is only meaningful across every outcome. On the group and exact-round presets the board already lists every outcome, so the box ticks itself once every row holds a valid price; untick it if the bookmaker’s market is missing an outcome. On a custom list you tick it yourself once every outcome of the market is entered. With it unticked, or with any row empty, the result panel shows the share of the book covered so far and leaves out the words margin and fair odds.

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Implied probability round by round

Every price hides a percentage. The calculator converts each fraction to a decimal by adding one, so 9/2 becomes 5.50, and then divides one by that decimal: 1 ÷ 5.50 is 18.18%. That is the implied chance, the probability at which the price would be exactly fair if there were no margin. The board shows it next to every row, so you can read a long list of fractions as a list of chances instead.

In the example, the red corner is the clear favourite. The four red groups are priced 9/2, 4/1, 5/1 and 8/1, which imply 18.18%, 20.00%, 16.67% and 11.11%, and red on points at 3/1 implies 25.00%. The blue corner’s groups run from 14/1 to 20/1, between 4.76% and 6.67% each, blue on points at 7/1 implies 12.50%, and the draw at 25/1 implies 3.85%. Adding the red rows gives a sense of how the whole book sees the fight, but only after the margin is taken out does the split add up to 100%.

The fair column does exactly that. It divides each implied chance by the book total, so red on points becomes 25.00% ÷ 131.28%, or 19.04%, and its fair decimal price is 4.00 × 1.3128, or about 5.25, which the table shows as ≈ 9/2, the nearest price on the UK ladder. On those fair numbers, the red corner stopping the opponent in one of the four groups comes to 50.24%, the blue corner doing so comes to 18.26%, and the fight going the distance, whether on points for either boxer or a draw, comes to 31.49%.

Which group of rounds is shortest

The result panel names the shortest price, the row with the highest implied chance, and labels it “most likely in this book”. In the example it is red on points at 3/1, 25.00%, and among the stoppage groups it is red in rounds 4–⁠6 at 4/1, 20.00%. That tells you how the bookmaker has spread its view across the fight, and it helps to read the groups as a set as well: in the example the four red groups together imply 65.96% against 25.00% for red on points, so this book sees a stoppage as the likelier way for the favourite to take the fight.

What the shortest price does not tell you is whether it is worth taking. It is the most likely outcome in this book, not the best bet, and the calculator never uses words such as value. A shorter group simply covers more of the chance the bookmaker gives that boxer; whether that chance is right is a question about styles, durability and the scheduled distance, which our boxing betting tips guide covers.

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The margin in a round market

Add up every implied chance in a full market and you get the book. In a market with no margin it would come to exactly 100%. In the example it comes to 131.28%, so the margin is 31.28%: for every 100% of real chance, the prices add up to 131.28%. The headline in the result panel shows that figure to two decimal places, and the fair-price table underneath adds back up to 100.00%.

That margin is large, and it is typical of round markets. The same example fight priced as a simple three-way result in our three-way margin calculator carries 10.36%. The difference comes from the number of outcomes: a bookmaker trims a little from each of eleven group prices, or twenty-seven exact-round prices, and the trims add up. It is the main reason group and exact-round prices look generous one by one and less so as a set.

If a full market ever adds up to less than 100%, the tool still shows the result, with a negative margin and the note “Below 100% — check that every price is for the same fight and the same market.” In practice that almost always means a price from another market, another bookmaker or an old screen has slipped into the list.

A worked example with a missing price

Load the example prices, then delete the 25/1 on the draw. The board still shows the decimal and implied chance for the ten remaining rows, and the line under it reads “Fill in the 1 empty price to see the margin.” The result panel switches to “Share of the book covered: 127.44%”, the sum of the ten prices entered, and names red on points as the shortest price so far. Type 25/1 back in and the full result returns: book 131.28%, margin 31.28%, shortest price red on points. The same check is a quick way to confirm you have copied every row of a long exact-round market before you read its margin.

What the calculator does not do

The tool reads prices; it does not settle bets. Most UK bookmakers count a boxer who does not come out for the next round as stopped in the previous round, and a fight changed from twelve rounds to ten after you bet usually voids round markets, but the wording differs from book to book. It removes the margin in proportion to each implied chance, which is the most common method; other methods move more of the margin onto the long prices and give slightly different fair odds. It does not fetch live prices or compare bookmakers on a round market, and it takes no stake and shows no return. Everything runs in your browser and nothing is stored. For the full picture of how these markets work, read our guide to round and group-round bets, and find the other calculators on our tools page or the guides from the homepage.