There is no universal number. The right risk per trade is the one whose worst case you can hold, and your own trade history defines that worst case: your loss streaks and drawdown profile scale with the risk you choose. Size from the worst runs, not the average ones, then test the level against your trades before trading it.
Your strategy's worst runs and your capacity to sit through them. The common defaults, 1% or 2% of the account per trade, are starting points rather than answers, because the same 1% produces a mild drawdown on a smooth system and a brutal one on a streaky system. The deciding inputs are yours: the loss streak distribution, the drawdown profile, and the floor you cannot cross, whether that floor is a prop firm limit or your own tolerance.
Sizing from averages is the common mistake. The average month never breaks an account. The worst stretch does, so the worst stretch is what the risk level has to survive.
No edge survives being oversized.
Directly. Expressed in R, your trade history is fixed: a 25R drawdown is a 25R drawdown at any size. The risk per trade converts it to money. At 0.5% risk that run costs roughly 12% of the account; at 2% it costs roughly half, with compounding bending the exact figure. Same strategy, same trades, and the difference between an annoyance and an account on the floor is the sizing dial alone.
This is why the sizing question comes after the drawdown question. Reading whether a drawdown is normal tells you the range in R your strategy produces; the risk per trade decides what that range does to your balance. Set the dial so the deep end of the range lands somewhere you can stand.
They separate the strategy from the sizing. One R is the amount risked on a trade, so a log in R multiples records the quality of the decisions with the size stripped out. A 2R winner means the trade paid twice what it risked, at any account size. That makes histories comparable across accounts, keeps the math honest, and lets you test the same trade record at different risk levels without rebuilding anything.
Quantprove reads R multiple logs natively, and the getting started guide covers the format. The whole sizing exercise in this article is an R exercise: the trades stay fixed while the percentage risked per R changes underneath them.
Run your own trades through a simulation at that level. Quantprove's prop firm simulator takes your history, sets a risk per trade, and reports the probability of hitting a target without breaching a loss floor across thousands of resampled runs, which is the sizing question in its sharpest form. The personal account view runs the same resampling without challenge rules and reports final capital and total return at the size you chose.
The pattern worth watching is asymmetry. Raising risk speeds the good paths a little and deepens the bad paths a lot, because breach floors and deep drawdowns cut compounding short. Watching the pass probability fall as the risk dial rises, on your own trades, teaches the limit faster than any rule of thumb. The prop firm guide walks the full challenge version.
More risk buys speed on credit, and drawdowns collect the interest.
Because streaks are where sizing fails. A 70% win rate produces a six loss streak often enough to matter over a few hundred trades, and the drawdown wrapped around a streak runs deeper than the streak alone. At 1% risk, six straight losses cost about 6% plus the surrounding bleed. At 3%, the same ordinary streak approaches 20%, and a prop account is gone before the strategy gets to be right.
Your loss streak distribution turns this from worry into arithmetic. Take the streak length your history produces routinely, multiply by candidate risk levels, add room for the deeper drawdown around it, and check each result against your floor. The level that keeps an ordinary worst stretch comfortably above the floor is the one your data supports.
Every consequence scales from one number. The table reads your fixed trade history at different risk levels.
| Risk per trade | What it does | Fits |
|---|---|---|
| 0.25% to 0.5% | Shallow drawdowns, slow compounding, wide margin to any floor | Thin track records, prop challenges, streaky systems |
| 1% | The common default; moderate drawdowns on most profiles | Validated systems with known streak behavior |
| 2% | Drawdowns double the 1% case; ordinary streaks bite | Smooth, proven profiles with real margin |
| 3% and up | Routine streaks threaten the account or the limit | Rarely survives contact with a normal worst run |
Bands are illustrative; your own loss streaks and floor set the real boundaries. The deeper question underneath the dial is the probability that an account ever reaches its floor at all. That number has a name, risk of ruin, and it is the single statistic that ties win rate, payoff, and sizing into one survival number.