The formula
Always round down. Rounding up quietly raises your risk on every trade.
A worked example
A $25,000 account risking 0.75% per trade has $187.50 to lose on each idea.
Three different markets, three different sizes, one identical risk. That is the whole point: your results then measure your decisions, not how big you happened to trade that day.
Common mistakes
- Assuming every pair pays $10 a pip. That holds for pairs quoted in USD on a USD account. USD/JPY or EUR/GBP pay a different amount, see pip.
- Choosing the size first and the stop second. The stop belongs where the idea is wrong. Size follows from it, never the other way round.
- Sizing up after losses. Doubling size to win it back is how a normal losing streak becomes a blown account.
- Leaving out costs. On a tight stop, commission and spread can add 10% or more to the real risk.
How the RB journal tracks it
The journal has a built-in Position Size Calculator that works out lot size and pip value, and it sits docked beside the chart in the backtester. On accounts with a daily loss limit, a pre-trade daily-loss guard appears when a trade's worst-case loss would burn a meaningful share of that day's loss budget, so oversizing gets caught before the order, not after.
See your own Position Sizing from real trades
Log trades by hand, import a file, or live-sync MT4, MT5 and cTrader through the RBSync EA. The numbers on this page then come from your own history instead of examples.
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