A race with a clock and two walls
A challenge asks for a profit target before a time limit, without breaking a daily loss limit or a maximum drawdown. Risk per trade is the one number that moves all three. Smaller risk makes the walls harder to hit and the target slower to reach. Larger risk does the reverse. That is why the answer to "how much should I risk" is not a single rule of thumb.
Firms differ and change their rules, so use the current terms of the firm you trade with. This guide uses no firm's rules, is not affiliated with any prop firm and is for education only. It is not financial advice.
What the simulator shows for one example
The setup is the site's default example: a 45% win rate, 1.5R winners and 1R losers, two trades a day, a 10% profit target, a 5% daily loss limit, a 10% static drawdown, 4 minimum trading days and a 30-day limit. Each row below is 5,000 simulated attempts from the prop firm challenge simulator.
| Risk per trade | Pass | Daily loss breach | Drawdown breach | Out of time | Median days to pass |
|---|---|---|---|---|---|
| 0.25% | under 1% | 0% | 0% | 100% | 29 |
| 0.5% | 15% | 0% | 1% | 84% | 24 |
| 0.75% | 38% | 0% | 4% | 57% | 19 |
| 1% | 56% | 0% | 10% | 33% | 15 |
| 1.5% | 68% | 0% | 21% | 11% | 11 |
| 2% | 69% | 0% | 30% | 1% | 7 |
| 3% | 24% | 76% | 0% | 0% | 4 |
Three things stand out. At the smallest sizes almost every attempt ends because time runs out: 100% at 0.25% and 84% at 0.5%. In the middle the pass rate rises, to 56% at 1% and 68% at 1.5%, and the drawdown starts to claim attempts: 10% at 1%, 21% at 1.5%. At 2% the pass rate is 69%, about the same as 1.5%, but 30% of attempts end on the drawdown. At 3% the daily limit takes over, because two losing trades in a day lose 6%, more than the 5% limit, and 76% of attempts end that way.
Why the daily limit sets a hard ceiling
The number of full losses that fit inside the daily limit is the daily limit divided by the risk per trade. At 1% risk a 5% limit takes 5 losses. At 2% it takes 3 (the third reaches it). At 3% the second does. With several trades a day, a run of losses is not rare, so the risk size has to leave room for it. The daily loss limit calculator turns your own limit into a table: to survive 3 losses in a row with room for a fourth, risk at most the budget divided by 4, which is 1.25% on a fresh 5% day.
The highest pass rate is not always the right size
In this example the best size in the table is 2% (69% pass), but the neighbouring sizes are close and breaches grow quickly past it. A size that wins the table can be one you cannot follow after three losses, which is a practical problem a simulator does not model. Where two sizes pass about equally often, the smaller one usually has fewer breaches.
How to choose a size for your own challenge
- Put in your real rules. Target, daily limit, drawdown type, minimum days and time limit, from your firm's current terms.
- Use an edge you have measured. A win rate and average win and loss from a large number of trades, not from a good month. Then look at the "win rate 5 points lower" line: if the pass rate collapses, the plan is fragile.
- Read the risk sweep. Look for the region where the pass rate is high and neither breach column is large, not for the single best row.
- Check it against the daily limit. The number of losses in a row it allows should be more than you would be comfortable seeing in a day.
- Convert it to size. The prop firm position size calculator turns a dollar risk and a stop distance into contracts or lots, and shows what share of today's budget the trade uses.
Passing is not the same as staying funded afterwards. A risk size chosen to reach a target quickly can be too large to keep. The same exercise is worth repeating for the size you will use after the target is reached.
Try it with your own numbers
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Quick questions
What risk per trade is best for a prop firm challenge?
There is no single best size. In the site's example, 1% to 2% passed most often (56% to 69%), but breaches grew with size and 3% failed on the daily limit. Use the simulator with your own rules and edge.
Is 1% risk too low to pass?
It can be, if the time limit is short. In the example, 1% risk passed 56% of attempts and 33% ran out of time. A longer time limit or more trades per day changes that.
Should I risk more to pass faster?
More risk shortens the race but makes both loss limits easier to hit. The simulated pass rate rose from 1% to 1.5% risk and then flattened at 2%, while drawdown breaches kept growing.
Find setups worth sizing.
A challenge rewards a steady edge. These indicators help you look for setups with room to run and clear invalidation.
Keep reading
Last updated November 2026. For education only. Not financial advice.