Daily drawdown is the most misunderstood rule in prop trading, and breaching it is one of the most common reasons challenges fail. It caps how much an account can lose within a single trading day, reset at a fixed time regardless of your open positions.
Two Calculation Methods
Firms typically calculate the daily limit from one of two reference points, and this distinction matters enormously for how much real risk you can take.
| Method | Reference point | Effect |
|---|---|---|
| Balance-based | Start-of-day closed balance | Floating losses during the day don't tighten the limit further |
| Equity-based | Start-of-day balance including any open floating P/L | Open losing trades can bring you closer to the limit in real time |
Under an equity-based daily drawdown, an open floating loss counts against your limit even before you close the trade. A large open drawdown can breach the rule intraday even if you never realize the loss. Always confirm which method your firm uses.
Example
Say you have a $100,000 account with a 5% daily drawdown limit ($5,000). Under balance-based calculation, the limit is fixed at the previous day's close regardless of intraday swings. Under equity-based calculation, if you're already down $3,000 in floating losses, you only have $2,000 of additional room before breach — even if none of it is realized.
Daily Drawdown Limit = Reference Balance × Daily Loss %When Does the Day Reset?
The 'trading day' cutoff is defined by the firm's server time, not your local time zone — commonly a fixed time such as 00:00 platform time. Trades open across that boundary are typically counted toward the next day using the new reference balance. Always check the exact reset time and timezone in your firm's rules.
Practical Ways to Avoid Breaching It
- ▸Size positions so that a full stop-loss hit on all open trades stays well under the daily limit — not just under, but with a buffer.
- ▸Know whether your firm uses balance- or equity-based calculation before you size any trade.
- ▸Set a personal daily loss stop well inside the firm's limit (e.g. half of it) and stop trading for the day once hit.
- ▸Avoid holding large positions across the daily reset boundary if you're unsure how it's treated.
The most reliable way to never breach a daily limit is to never approach it. Treat a fraction of the actual limit — such as 50%—as your real ceiling for the day, and stop trading once you touch it.