The arithmetic is trivial. The point is elsewhere.
daily limit = balance × daily %
room left = daily limit − lost so far
trades left = room left ÷ risk per trade
A $25,000 account with a 1% per-trade risk and a 3% daily cap has $750 for the day and $250 a trade — three full-size trades before the day is over.
That number is the whole product. Not the percentage, not the philosophy: the count of trades remaining, visible before the session rather than reconstructed after it.
Why the limit needs to exist before the day starts
A per-trade limit protects against one bad decision. A daily limit protects against the sequence that follows one, and the sequence is where accounts actually die.
The pattern is consistent enough to be predictable: two losses, then a larger position to recover them, then a third loss that is bigger than the first two combined. Nothing in that chain violates a per-trade rule — each trade can be exactly 1% — and the day still ends down 8%.
The limit works by being decided when nothing is at stake. Its entire purpose is to bind the version of you that has lost three in a row and can see precisely how to get it back.
The moment the rule gets rounded up
There is a specific state the calculator warns about: what remains is smaller than one full-size trade.
$180 left against a $250 normal position. The choices are a reduced position, which is inside the rule, or a normal one, which is not — and the second requires only a small mental adjustment that nobody would notice.
This is where daily limits are actually broken. Not by ignoring them, but by treating $180 as "basically $250" while already down for the day.
Choosing the numbers
Conventions rather than laws, and the internal consistency matters more than the exact figures:
- Daily limit at 2–3× the per-trade risk. At 1% a trade, a 3% day means three losses stops you.
- Weekly limit at roughly 2× the daily, so one bad day does not become a bad week.
- Monthly at 2× the weekly, as the point where the method itself gets reviewed rather than the sizing.
If the daily limit is ten times the per-trade risk, it is not a limit — it is a number that will never be reached before the damage is done.
On a funded account this stops being a preference. The firm's daily loss limit is a hard boundary that closes the account, and its rules on how it is measured — including whether open positions count — are covered on the prop drawdown calculator.