How the odds work
Every number on the tote board is a price. Once you can read the price, you can see what the game is really offering you, at Crab Derby and anywhere else that posts odds.
The American line
A plus number tells you what a $100 stake wins. Rehoboth Rocket at +250 pays $250 on $100, so you get $350 back. A minus number tells you what you must stake to win $100. Old Bay Betty at -150 needs $150 down to win $100, so $250 back.
The board also shows the same price two other ways: the decimal multiplier (3.50x means every dollar comes back as $3.50 if the crab wins) and the implied chance, which is what the price says about how often that crab should win.
Turning a price into a chance
Decimal odds are the easiest to flip. Divide one by the multiplier. 3.50x becomes 1 divided by 3.5, about 29 percent. 1.60x becomes about 63 percent. That is the share of races the crab would need to win for the bet to break even over time.
| Line | Multiplier | Implied chance |
|---|---|---|
| -200 | 1.50x | 67% |
| -110 | 1.91x | 52% |
| +100 | 2.00x | 50% |
| +250 | 3.50x | 29% |
| +600 | 7.00x | 14% |
Why the chances add up to more than 100
Add the implied chances of all six crabs on the board and you get about 108 percent. Six crabs cannot win 108 percent of the time. The extra 8 points are the take, the tote's cut. Every price on the board is shaved by that much, so the payout on a winner is always a little less than the true chance would pay.
At Crab Derby the take is a flat 8 percent and we print it on the home page as it adds up. Real tracks run between about 15 and 25 percent on exotic bets. Sportsbooks hide theirs inside the -110 on both sides of a coin flip, which works out to about 4.5 percent per bet. Prediction markets charge a fee on winnings instead, which lands in the same place.
Why the take beats your picks
Picking winners feels like the whole game. It is not. Suppose you are genuinely good and your crab wins exactly as often as the true odds say. You still lose the take on every dollar, race after race, because the price you were paid was shaved before you ever chose. Over a hundred races at $10 a race that is $80 gone to the board whether you picked well or badly.
The only way to come out ahead over time is to find prices that are wrong by more than the take, and the board sets the prices. That is the entire business model of every book, track and casino, and it is why the meter on the home page shows the take and not your win rate.
What this game does with that
The bankroll is play money and resets whenever you like. The odds come from each crab's form plus the tide, with the 8 percent take applied exactly the way a tote does it. The ledger keeps score, and the take meter keeps the honest score. Race as much as you like. It costs nothing, which is the point.