Baseball Betting
Stolen Base Probability Calculator
Calculate estimated event probability with user assumptions, a worked example, source checks, and practical limitations.
Values used for estimated event probability
Keep signs, odds formats, percentages, and event periods consistent.
The question behind the result
For Stolen Base Probability, opportunity and conversion are kept separate here: Expected opportunities measures volume, Probability per opportunity measures per-chance success, and Events needed defines the selected event.
Opportunities depend on reaching base, runner intent, pitcher delivery, catcher quality, score, and inning.
Checks the arithmetic cannot perform
A rate from another runner or game state should not be transferred without adjustment.
On this page, a pitcher or lineup change can invalidate a projection before the posted price visibly moves.
How to source the fields
Expected opportunities records number of relevant attempts or chances.
Within this calculation, do not copy a sample default into a live case without checking its source.
After documenting estimated event probability, the First Five Innings Run Line can answer another question.
Calculation method and assumptions
Formula: probability = binomial chance of reaching the event threshold.
For this market, every change can be traced to a visible field or the formula.
Comparing two plausible cases
For rare events, review whether the rate can remain stable and opportunities independent.
To compare pitcher walks allowed separately, open the Pitcher Walks Allowed after saving this baseline.
Worked numbers
- Expected opportunities: 2 opportunities
- Probability per opportunity: 12.96%
- Events needed: 1 event
Applying the Stolen Base Probability rule: probability = binomial chance of reaching the event threshold.
Fair odds is +313. Expected events is 0.26. Probability below threshold is 75.76%.
As a practical check, keep the example separate from the saved market case.
Where the method can break
At this stage, the page cannot determine whether a sportsbook applies a settlement exception.
The home run probability portion belongs in Home Run Probability; the two calculations answer different questions.
What to save with the result
Connecting the inputs to the outcome
This calculator answers the task stated on the page—Estimate the chance of at least one stolen base from opportunities and a per-opportunity rate. It does not automatically answer a staking, payout, or unrelated prop question. Keep Expected opportunities and Probability per opportunity attached to this purpose so the meaning of Estimated event probability does not drift during later comparisons.
If two sources disagree about Probability per opportunity, do not average them automatically. Examine whether they use the same sample, participant role, and event window; then select or preserve separate cases. Apply the same rule to Events needed so Estimated event probability reflects an explainable choice.
A useful audit can be performed without changing the formula. Re-enter Events needed, verify Expected opportunities, and reproduce Estimated event probability from the saved case. Only after the answer matches should new information be introduced, one field at a time, with the original output retained for comparison.