Over 200 trades at a 55% win rate the longest losing streak is typically six, and one record in six reaches eight or more
Our own calculation, 7 November 2026 (UTC), for the article "Is a win due?". Way 1: the exact distribution of the longest losing run, computed by stepping through the trades one at a time and tracking the current run length. Way 2: simulation with a fixed seed (40,000 records of 200 trades, 10,000 of 1,000, 40,000 rows of 100 coin flips). The two agree within simulation noise.
What we found
- 200 trades at 55%: the longest losing streak is 6 in the typical record (median); 9 records in 10 stay at or below 8; a streak of 8 or more has a chance of 16.5% (about one in 6; simulated 16.3%), 9 or more 7.7% (one in 13), 10 or more 3.5% (one in 28; simulated 3.5%), 7 or more 33.4% (about one in three).
- 1,000 trades at 55%: the typical longest streak is 8; 10 or more 17.0% (one in 6; simulated 17.0%); 11 or more 8.0% (one in 12).
- 200 trades at 65%: the typical longest streak is 4; 7 or more 7.8% (one in 13).
- 100 fair coin flips: the longest run of either side is typically 7; a run of 6 or more appears in 80.7% of rows (simulated 80.8%), about four in five; a row with no run longer than 3 has a chance of 2.8 in 10,000, about three in ten thousand.
- The approximation L = ln(n x (1 - q)) / ln(1 / q) gives 5.9 at 200 trades and q = 0.45, against the exact median of 6.
- In 200,000 trades the windows where the last five all lost number about 3,690 ((200,000 - 5) x 0.45^5), about 3,700.
What this cannot tell you: whether a real strategy's edge has changed; the figures assume independent trades at a fixed win rate.
The figures as the article's table states them
| Figure | Value |
|---|---|
| Typical longest losing streak, 200 trades at 55% | 6 losses |
| Longest losing streak that 9 runs in 10 stay at or below, 200 trades at 55% | 8 losses |
| Chance of a streak of 8 or more, 200 trades at 55% | 16.5% |
| Typical longest run of one side, 100 fair flips | 7 |
| Chance a fair coin's next flip is heads after 7 tails | 50% |
- The typical longest losing streak over 200 trades at 55% is 6 losses; 9 runs in 10 stay at or below 8 losses; the chance of a streak of 8 or more is 16.5%; the typical longest run of one side in 100 fair flips is 7.
- The chance a fair coin's next flip is heads after 7 tails is 50%: each flip is independent of the ones before it.