Streak Betting Calculator
Win or loss streak probability.
How to Use This Calculator
- Input your single-bet win probability as a percentage (e.g., 55)
- Input the streak length you want to assess
- Input the total number of bets
- Read streak probability and expected longest run
Formula
P(streak of N wins) = p ^ N
P(streak of N losses) = (1 − p) ^ N
Expected Longest Run (approx) = log(N · (1 − p)) / log(1 / p)
P(≥ 1 winning streak of length N in M bets) ≈ 1 − (1 − p^N)^(M − N + 1)
Frequently Asked Questions
Why is my expected longest streak so long?
Variance scales logarithmically with sample size. Across 1000 coin flips you typically see a run of 9-10 heads. Long streaks feel startling yet are mathematically expected — most bettors misread them as hot/cold phases instead of ordinary variance.
How does streak length bear on bankroll management?
Even a 60% win rate routinely throws up 5+ losing streaks. Bankroll management (Kelly fractions, flat staking) has to absorb these without ruin. Run this calculator at a streak length of 5-7 to gauge how often those losing runs hit, then size your unit accordingly.
Do sports streaks predict anything?
Largely no. Independent events (coin-flip-like markets) generate streaks by pure chance. Small predictive effects exist (injury cascades, team morale) but are usually overstated. Treat past streaks as variance unless you have concrete model-based reasons not to.
What is the math behind 'expected longest run'?
For independent Bernoulli trials with success probability p over N trials, the expected longest run of successes converges to log(N(1−p))/log(1/p). This logarithmic approximation is accurate for large N and yields the typical longest streak you would observe.