Why the daily rule ends more challenges than the max rule
The maximum-drawdown rule gives you the whole account's depth to work with; the daily rule resets a much smaller allowance every morning and counts your open positions against it in real time. A $100,000 account with a 5% daily rule has $5,000 of room — two normal-sized losses and a floating position underwater can consume it before lunch. The arithmetic is trivial; the failure mode is not knowing the live number while trading. That's what the headroom output is: the exact dollar figure between you and the line, on the definitions you entered.
Baseline and floating: the two definitions that vary
Firms disagree on two things, and this calculator makes both of them your inputs instead of our assumptions. The baseline: some firms snapshot your balance at the day's start, others your equity — enter whichever your rulebook names. Floating P&L: most firms count open positions against the limit (a trade $2,000 underwater consumes $2,000 of room even if you never close it), a few count only realized losses — set floating to zero if yours is one of them. The formula stays the same either way: headroom equals the limit minus today's combined loss.
Using the number before the next trade
The practical read is the last line of the result: the size of loss that would cross the line right now. If your next trade's worst case — stop distance times position size — is bigger than that number, the trade can end the day regardless of how good the setup is. Either size down until the worst case fits inside the headroom, or stop for the day. For the same buffers computed live from your actual positions on the chart instead of typed inputs, the prop-rules dashboard does this continuously. Nothing you type here leaves your browser.