How Long a Losing Streak Should You Expect? The Math by Win Rate
At a 50% win rate, the longest losing streak in 100 trades is usually 6. About 1 trader in 23 with that same edge will see 10 or more in a row over those 100 trades, and nothing will be wrong with their strategy. Drop the win rate to 40% and the usual longest streak becomes 7, with 12 or more in about 1 journal in 13.
These numbers come from exact probability math for independent trades. The tables below cover win rates from 30% to 70% and samples from 50 to 500 trades, so you can look up what normal looks like for your own numbers before a streak starts, while you can still think about it calmly.
The short version
• Losing streaks are longer than they feel. At a 50% win rate, 5 losses in a row starting from any given trade is a 1 in 32 event, but over 100 trades the chance of seeing at least one run of 5 is 81.0%.
• The longest streak grows with the number of trades. At a 45% win rate it’s usually 6 over 100 trades and 8 over 200.
• A quick formula gets within one trade of the exact answer: longest streak ≈ ln(trades × win rate) ÷ ln(1 ÷ loss rate).
• Size your risk for the rare streak. At a 45% win rate over 200 trades, 12 losses in a row costs 11.4% of the account at 1% risk per trade.
• A streak past the rare line in the table is a reason to review your trades. It doesn’t prove the edge is gone.
Longest losing streak by win rate
Each cell has two numbers. The first is the typical longest streak: half of all journals with that win rate and trade count have a longest streak at least this long. The second is the rare line: 95% of journals stay at or under it, so at most 1 in 20 goes past it.
| Win rate | 50 trades | 100 trades | 200 trades | 500 trades |
| 30% | 8 / 15 | 10 / 17 | 12 / 19 | 15 / 22 |
| 35% | 7 / 13 | 9 / 14 | 10 / 16 | 12 / 18 |
| 40% | 6 / 11 | 7 / 12 | 9 / 14 | 11 / 16 |
| 45% | 5 / 9 | 6 / 11 | 8 / 12 | 9 / 13 |
| 50% | 5 / 8 | 6 / 9 | 7 / 10 | 8 / 12 |
| 55% | 4 / 7 | 5 / 8 | 6 / 9 | 7 / 10 |
| 60% | 4 / 6 | 4 / 7 | 5 / 8 | 6 / 9 |
| 65% | 3 / 6 | 4 / 6 | 4 / 7 | 5 / 8 |
| 70% | 3 / 5 | 3 / 5 | 4 / 6 | 5 / 7 |
Going from 100 to 500 trades adds only 1 to 5 losses to the typical streak, because the longest streak grows with the logarithm of the trade count. And a low win rate stretches everything: at 30%, a 10-loss run is the typical longest streak in 100 trades.
The table assumes every trade is a win or a loss and that each trade is independent of the ones before it. The limits section covers what happens when that’s not true.
Why streaks run longer than they feel
Most traders judge a streak trade by trade. After 4 losses, the next one feels like it has to win. At a 50% win rate the chance of 5 losses in a row starting from a given trade is 3.12%, about 1 in 32, so a run of 5 feels rare.
The journal view is different. Over 100 trades there are close to 100 places a streak can start, and the question becomes whether any of them turns into a run. That’s much more likely:
| At least this many losses in a row | 40% win rate | 50% win rate | 60% win rate |
| 4 | 99.9% | 97.3% | 80.1% |
| 5 | 97.6% | 81.0% | 45.9% |
| 6 | 87.3% | 54.6% | 21.2% |
| 7 | 68.9% | 31.8% | 8.9% |
| 8 | 49.0% | 17.0% | 3.6% |
| 10 | 20.5% | 4.4% | 0.6% |
| 12 | 7.7% | 1.1% | 0.1% |
Chance of at least one streak that long within 100 trades.
A 60% trader still has close to even odds (45.9%) of hitting 5 losses in a row within 100 trades. At 40%, a run of 8 is a coin flip.
A quick formula
If your numbers aren’t in the table, this estimate gets within one trade of the exact typical figure in every cell above:
longest losing streak ≈ ln(N × W) ÷ ln(1 ÷ (1 − W))
N is the number of trades and W is your win rate as a decimal. At a 50% win rate over 100 trades: ln(50) ÷ ln(2) = 5.6, against an exact typical value of 6. In Excel or Google Sheets, with trades in A1 and win rate in B1:
=LN(A1*B1)/LN(1/(1-B1))
The formula gives the typical streak only. For the rare line, use the table or the risk of ruin calculator, which simulates 5,000 runs of your win rate, reward-to-risk and position size and reports the losing streak along with the drawdown.
Worked example: a 45% win rate over 200 trades
Take a hypothetical trader with a 45% win rate who places 200 trades over a quarter, about 3 trades a trading day. The math for that journal:
• Typical longest losing streak: 8. The chance of at least 8 in a row somewhere in the 200 trades is 53.0%.
• At least 6 in a row: 93.0%. At least 10: 19.9%. At least 12: 6.4%. At least 14: 1.9%.
• 95% of journals stay at or under 12 losses in a row, and 99% stay at or under 15.
• On average, the 200 trades contain 4.5 separate streaks of 5 or more losses. A streak of 8 or more shows up 0.7 times on average.
To see what one journal looks like, the script drew a single seeded run of 200 trades at a 45% win rate. It had 83 wins, a measured win rate of 41.5%, a longest losing streak of 9 and a longest winning streak of 6. The win rate came in 3.5 points under the true 45% by chance alone, and the trader would have seen 9 losses in a row from a strategy that was working exactly as designed.
What a streak costs depends on the risk per trade. With a fixed percent of current equity at risk on each trade, the drawdown from the streak alone is:
| Risk per trade | 8 losses | 12 losses | 15 losses |
| 0.5% | 3.9% | 5.8% | 7.2% |
| 1% | 7.7% | 11.4% | 14.0% |
| 2% | 14.9% | 21.5% | 26.1% |
| 3% | 21.6% | 30.6% | 36.7% |
At 1% risk the rare streak of 12 costs 11.4%, past a 10% maximum drawdown limit. To keep 12 losses in a row inside 10%, the risk per trade has to stay at or under 0.87%. Our post on risk of ruin shows how the chance of hitting a drawdown limit changes as risk per trade goes up.
How to use the table on your own trades
1. Take your win rate from your closed trades. A win rate from 30 trades can be off by 15 points or more, so use at least 100 if you have them. Our guide on how many trades you need before evaluating a strategy covers sample size.
2. Pick the window you want to plan for, such as the number of trades you take in a quarter.
3. Read the typical and rare streaks for that win rate and trade count.
4. Work out the drawdown of the rare streak at your risk per trade: 1 − (1 − risk)^streak. If it breaks a limit you trade under, such as a prop firm’s maximum loss, lower the risk until it fits.
5. Write a review rule at the rare line before the streak happens. For the example trader, that’s 13 losses in a row within a quarter.
6. Count your longest losing streak at each review. A helper column does it: in C2, =IF(B2=”L”,C1+1,0), filled down, then =MAX(C:C), where column B marks each trade W or L.
Use the review rule to check the trades, and leave the strategy as it is until the review is done. Check whether each losing trade followed your plan and whether your position size stayed where it should be. Then compare recent market conditions with the ones your edge was built on. Our drawdown analysis guide has a fuller review routine.
Checking whether your streak is unusual
Say a trader has a 55% win rate and just lost 9 in a row somewhere in their last 150 trades. For that win rate and trade count, the typical longest streak is 5 and the rare line is 9. The chance of at least 9 losses in a row in 150 trades is 5.8%.
That puts the streak right at the edge of normal variance. It’s worth a review. It isn’t enough on its own to say the edge has gone, because about 1 trader in 17 with a working 55% strategy would see the same thing.
Two checks help separate bad luck from a broken strategy:
• Rerun the numbers on the recent trades. Put the current win rate, average win and average loss into the trading expectancy calculator and compare the expectancy per trade with your longer history.
• Compare the win rate with your breakeven. The breakeven win rate calculator shows the win rate your reward-to-risk and costs need. A recent win rate under breakeven on a sample of 50 trades or more is a stronger signal than one long streak.
If the streak came with bigger positions or trades outside your plan, look at your own trading behavior first. Our guide on how to stop revenge trading covers sizing up after losses, and the post on position size creep covers sizing up after wins.
Limits of this math
• It assumes independent trades. Trades can cluster: a strategy can lose several trades in a row in one market condition, and a trader on tilt can turn one loss into four. Clustering makes long streaks more common than the table shows. If your journal keeps beating the rare line, check for it.
• Your win rate is an estimate. A trader with 50 wins in 100 trades has a 95% range of about 40.4% to 59.6% for the true win rate. At 40%, the rare line for 100 trades is 12. At 50% it’s 9. Planning with the lower end of the range is safer.
• Breakeven and scratched trades need a rule. The table counts every trade as a win or a loss. Decide whether a scratch breaks a streak, and apply the same rule every time you count.
• Streak length says nothing about the size of each loss. A streak of 6 losses at 1R each and a streak of 6 where 2 losses ran past the stop to 2R cost different amounts. Track results in R alongside the streak count.
FAQ
Does a losing streak make my next trade more likely to win?
No. If your trades are independent, the chance of winning the next trade is your win rate, however many losses came before it. After 5 losses at a 50% win rate, the sixth trade is still a 50% trade.
What is a normal losing streak for a 50% win rate?
Over 100 trades the typical longest streak is 6, and 95% of journals stay at 9 or fewer. At least 10 losses in a row shows up in 4.4% of 100-trade journals.
How many losses in a row should make me stop and review?
A common choice is the rare line from the table for your win rate and the number of trades in your review window. A rule set lower than that fires during normal variance. The review is a check of the trades and the plan, and it works best when it’s written down before the streak starts.
How do I find my longest losing streak in a spreadsheet?
Mark each closed trade W or L in column B, in the order you took them. In C2 enter =IF(B2=”L”,C1+1,0), fill it down, and take =MAX(C:C). Scratched trades need a rule: count them as losses, as wins, or skip them, and use the same rule every time.
Run it on your own trades
UltraTrader auto-syncs trades from MT4, MT5, cTrader and crypto exchanges over a read-only connection, so your full trade history is in one place without retyping it. The journal shows your win rate and R:R metrics, plus a performance calendar. Try UltraTrader.
The probabilities in this post are exact calculations for independent trades, and the worked example is a hypothetical journal. Results depend on the inputs and are not a prediction of future performance. This is educational content, not financial advice.