Why this calculator does not know your firm
Most tools like this offer a dropdown of firm names and promise an exact figure. This one asks you to type the numbers yourself, and that is a deliberate choice.
Prop firm rules change, sometimes with short notice and sometimes affecting existing accounts differently from new ones. A tool that quotes a rule from a blog post written months ago will be confidently wrong at exactly the moment it matters. One blown account explained by "your calculator said I still had room" costs more than this page will ever be worth.
So the arithmetic here is honest arithmetic on numbers you supply, and every ambiguity resolves toward the conservative answer. Where a figure is missing, the calculator assumes the version that leaves you less room, not more.
The three drawdown types, and why they are not interchangeable
The words look similar on every firm's rules page. The mechanics are not.
Static. The floor is fixed at the starting balance minus the limit. A $50,000 account with a $2,000 max loss can never go below $48,000, no matter how much it makes first. Profits raise your buffer; the floor never moves.
Trailing (intraday). The floor follows your highest point, including the highest point reached inside a trade. Make $800 on an open position, give it back, and the floor has already moved up $800 — your buffer shrank without a single losing trade being closed. This is the type that surprises people most.
Trailing (end-of-day). The floor follows your closing balance each day rather than your intraday peak. It is more forgiving than intraday trailing, but the label carries a trap of its own.
The end-of-day trap
Some firms trail the drawdown on the end-of-day balance and still monitor the account in real time, counting unrealised losses on open positions. Both statements are in the rules, and read separately they suggest opposite things.
The practical result: a trader reads "end-of-day drawdown", concludes the limit cannot move against them during the session, sizes the day accordingly — and the account fails at two in the afternoon on an open position that was never closed.
"End-of-day" describes when the floor is recalculated, not when you are safe. Whether unrealised losses count against your limit is a separate question with a separate answer, and it is worth finding the exact sentence in your own firm's rules rather than inferring it. If your firm counts open equity, treat the intraday setting above as the honest one.
Balance or equity — the other question that decides the number
The second thing to check is which figure the limit measures.
- Balance counts closed trades only. An open position sitting at −$400 has not moved the number yet.
- Equity counts everything, including floating profit and loss.
Two firms advertising the same "$2,000 maximum loss" can stop you hundreds of dollars apart, purely on this. It also explains the most common confusion in prop trading forums: someone is stopped out while their platform still shows a comfortable balance, because the firm was watching equity.
When your day starts
Daily loss limits reset on the firm's clock, not yours. Futures firms usually anchor the day to the exchange session, and forex firms to a specific timezone that may not be the one you live in.
If your day genuinely begins at 6pm your time and you assume midnight, then everything you trade in that window is measured against yesterday's allowance — which may be nearly used up. The mistake costs an account roughly once per trader, and only once.
What to do with the number
The figure this calculator gives you is a ceiling, not a plan. A working method is to take the smaller of the two remaining amounts and divide it by your normal per-trade risk: that tells you how many losing trades today can hold before the decision is made for you.
If the answer is one, the useful move is to stop, not to be careful.