Set it before the open
A loss limit decided during the session is not a limit. It is a negotiation with yourself, and the version of you that has just lost twice always wins it. Set the number before 9:30 and lock it.
Size it to survive three bad days
A useful limit is one you can hit three days in a row and still trade on Thursday. For a $5,000 account that is usually 1 to 2 percent a day, so $50 to $100. If that feels small, that is the point. Practice is where you learn to accept small.
What the limit is not
It is not a target. It is not a signal to size up to win it back. It is the line where the day ends.
Let the platform enforce it
The rule needs teeth. On Day Trading Demo you set the limit before the open. When your closed and open losses reach it, the demo closes your positions and ends the day. You do not get to click through it.
The day is then scored by rules kept, not by dollars. A green day where you broke the limit scores as a broken rule, because that is the day that eventually takes the account.
What to do after you hit it
- Write one sentence in the journal on what the losing trades had in common.
- Close the platform. Reviewing charts after a stop-out turns into revenge planning.
- Come back tomorrow with the same limit. Changing it after a loss is the same negotiation in different clothes.
Why this transfers to real money
Traders who moved from a demo to a live account describe the same thing: the sim let them trade through losses, so the first real losing streak had no rule attached to it. Practising the stop is the practice.