Position sizing answers two questions: how big (in lots, contracts, shares) and how much risk (in account % or absolute currency) does this single trade represent? Most disciplined traders work backward from risk: "I'm willing to lose €100 if my stop hits, my stop is 25 pips away, so the position size is whatever makes 25 pips equal €100." The exact lot size becomes the output, not the input.
The opposite — picking lot size first and shrugging at the resulting risk — is how accounts blow up. A 1-lot EURUSD position with a 50-pip stop costs $500. On a $10k account that's 5% risk. On a $50k account it's 1%. Same trade, totally different psychological pressure and survival math.
Account €20,000. Risk per trade 1% = €200. Stop distance 40 pips on EURUSD where 1 pip per standard lot ≈ €9.
Risk-per-trade bands and what they imply: - 0.25-1% risk per trade — institutional / long-survival sizing. Painful streaks are bearable. - 1-2% — typical disciplined retail. Workable if win rate and R:R are honest. - 2-5% — aggressive. Three losses in a row is now ~14% drawdown. You'll feel it. - Above 5% — gambling regime. One unusually bad streak ends the account. - Variable risk — bigger when you "feel sure," smaller when "uncertain" — usually a hidden tilt source. Discipline > gut.
Position Sizing is the difference between two traders with the same setup, same entries, same exits, same win rate — and totally different equity curves. Trader A risks 1% per trade and ends the year up 18%. Trader B risks 4% per trade on the same setups and ends the year flat after a drawdown that briefly hit -30%. Same edge. Different sizing.
In TradeOnyx every trade carries its risk-amount and risk-percentage at the time of entry. The dashboard knows what your account was, what you risked in absolute and relative terms, and whether that matched your declared Risk-per-Trade setting in the Profile tab. Trades that exceeded the declared risk get flagged automatically — both in the Trades-tab list and in the post-trade review.
The Profile-tab presets — `0.5%`, `1%`, `2%`, custom — let you set a guardrail, then the platform measures discipline against the guardrail with no further input from you. After 100 trades you'll have a clear, no-spreadsheet answer to "did I actually size the way I said I would?" Most of the time, the honest answer surprises the trader more than they expect.