Why streaks are longer than they feel
A 50% win rate does not mean win, lose, win, lose. It means that over many trades about half are winners, arranged at random. Random arrangements contain long runs. Over 100 trades of a coin-flip strategy, a run of 6 losses somewhere in the sequence is more likely than not, and 1 run in 6 contains 8 or more. Traders who do not know this abandon a sound strategy in the middle of a normal streak, or double their size to "win it back" at the worst moment.
How the calculation works
With win rate p, each trade is a loss with chance q = 1 - p. The calculator walks through the trades one at a time and keeps, for every possible current run of losses, the chance of being there without yet having hit the streak length you asked about. That gives the exact chance that a streak of that length appears at least once, for any number of trades. The cost of k losses in a row at a fixed share r of the current balance is:
Some websites use the shortcut log(trades) / log(1 / q) for the "expected" longest streak. It is only a rough guide: at a 50% win rate over 100 trades it gives 6.6, while the exact typical streak is 6, and a single number hides the spread: 1 run in 6 contains 8 or more.
Example 1: a 50% strategy over 100 trades
Typical longest streak: 6. 9 runs in 10 stay at or under 8; 99 in 100 at or under 12. Ten in a row happens in 4.4% of 100-trade runs. At 1% per trade, 8 losses cost 7.73% of the balance and need an 8.4% gain to recover.
Example 2: a trend follower, 35% over 200 trades
Low win rates are normal for trend strategies that let winners run. Typical longest streak: 10; 9 runs in 10 stay at or under 14; 99 in 100 at or under 20. Ten in a row happens in 61.6% of 200-trade runs. At 1% per trade, 14 losses cost 13.13%. Someone who expects "5 or 6 at most" will quit this strategy long before its edge can show.
Example 3: 60% over 1,000 trades
A high win rate does not protect you over many trades. Typical longest streak: 7, 9 in 10 at or under 9. Ten in a row: 6.1%, about 1 trader in 17.
Example 4: the same streak at 2% risk
45% win rate, 200 trades: 1 run in 5 (19.9%) contains 10 losses in a row. At 1% per trade that costs 9.56%; at 2% it costs 18.29% and needs a 22.4% gain to get back. The streak is the same; the risk per trade decides whether it is an annoyance or a disaster. The risk of ruin calculator gives the chance of a whole drawdown, streaks and wins mixed, and the position size calculator turns your risk per trade into lots.
Why a real streak can run longer
The calculator assumes every trade is independent and has the same chance of winning. Real trading bends both assumptions. A strategy that suits trending markets loses more often while the market ranges, so losses come in clusters. And a win rate measured on 50 trades is only an estimate: 25 wins out of 50 fits a true win rate anywhere from about 36% to 64% (the 95% range). Use the 9 runs in 10 number as the streak you plan for, and a streak beyond the 99 in 100 number as a signal to stop and check whether the strategy still works. The trading statistics guide shows how to tell the two apart.
Questions
- How many losing trades in a row are normal?
- It depends on the win rate and on how many trades you take. At 50% over 100 trades the longest streak is typically 6 and 9 runs in 10 stay at or under 8. At 35% over 200 trades it is typically 10, with 9 in 10 at or under 14.
- Does a losing streak mean my strategy stopped working?
- Not by itself. A streak shorter than the 9-in-10 number is ordinary bad luck. A streak longer than the 99-in-100 number is rare enough to take seriously: check your journal for broken rules, and check whether the market changed.
- Should I raise my size after several losses, because a win is "due"?
- No. With independent trades, the next trade has the same chance after 5 losses as after 5 wins. Raising size during a streak (martingale) makes the long streaks, which will come, far more expensive.
- Why is the drawdown bigger than the streak?
- A drawdown runs from a balance peak to the lowest point after it. A bad stretch of, say, 3 losses, 1 win, 4 losses is two streaks but one drawdown. So plan your risk per trade for a drawdown deeper than your longest streak, not equal to it.