Betting maths and calculators
How can a four-leg accumulator lose if three selections win?
Direct answer
Every included leg must win for a standard accumulator to pay; one losing leg defeats the combined wager.
How to use this answer
This answer is based on the mathematical principle or published rule identified in the source below. If the question involves a live betting market, confirm its settlement definition before applying it to a specific bet.
Use the precise stake, decimal odds, market terms and outcome probabilities when calculating the result. Expected value measures an average over hypothetical repetitions, not a guaranteed profit.