One position at a time is not the whole risk
A sizing rule applied position by position answers a narrow question: what one trade costs if its stop is hit. It says nothing about what happens when four of them are open at once. Each may sit at a comfortable 1.5% of the account, and each may be defensible on its own chart, and the account can still be carrying 6% against the market rather than 1.5%. The number that describes the account is the sum: every open position, the distance from its entry to its stop, multiplied by the units held, added together and read as a share of capital.
A fifth position does not dilute the first four, it stacks on top of them. Someone who keeps every trade inside the same per-trade percentage can still arrive at a day where the whole book is exposed at once, because nothing in the per-trade rule ever looked at how many trades were open. This page does that one job: it adds them up and puts the total against a limit typed in by the person using it.
When several positions are really one bet
The arithmetic here treats every position as independent. It adds the risks and stops there, because that is all it can honestly do with entries, stops and unit counts. Real books are rarely that tidy. Four long positions in four different miners, or in four names that move with the same index, are closer to one large bet than to four small ones. If the reason the first stop gets hit is the same reason the other three get hit, the day costs the whole total at once.
There is no formula on this page for that, and there is not one coming, because the honest version of the question is not arithmetic. It is a reading of what the positions have in common: the same sector, the same currency, the same commodity underneath them, the same release on the calendar. Six positions that are genuinely six ideas carry a very different total than six positions that are one idea entered six times, even when both add up to the same percentage here. How we group instruments before deciding whether two ideas are one is part of what our methodology covers.
Where the 6% comes from, and what it is not
The 6 sitting in the limit field is a default, not a recommendation, and it is editable for that reason. It comes from a convention that circulated widely in retail trading education: risk around 1% per trade, hold around six positions, and cap the total open risk near 6% of the account, trimming rather than adding once the cap is reached. Tidy arithmetic, easy to remember, which is much of why it spread.
What it is not is a law derived from anything. It carries no proof, it fits no particular account size, and it says nothing about the strategy the positions belong to. A book of slow trades held for months and a book of trades closed by the bell can both be run carefully at very different totals. The figure that belongs in the field is the one whose worst honest outcome the account can absorb. Anyone unsure what a given total costs once it goes against them can put it through our drawdown and recovery calculator, which turns a loss into the gain needed to get back to where the account started.
How to read each number
The headline is the open risk of the whole book as a percentage of capital: the sum of what every filled row loses at its stop, divided by the account. Money at risk in total is that same sum in currency, and the limit in money is the percentage typed above turned into a figure, so the two compare directly. Room left is the difference, and it goes negative when the book is already past the limit, because that is a real situation and rounding it up to zero would hide it. Each position also gets its own line.
The bar draws those same figures rather than adding new ones. Every block is one position on the scale the limit sets, in the order the rows were typed, and the mark is the limit itself. The color follows the total in three steps: below the limit, close to it, and past it. It restates a subtraction already made in the list.
The second mode runs the arithmetic backwards. Given the book as it stands, plus an entry, a stop and a direction, it returns the units that still fit inside the room left, rounded down to a whole unit. That is what our position size calculator does against a single-trade budget, except the budget here is whatever the rest of the account has not already spent. Where the room is gone the page says so instead of returning a quiet zero.
