The quick answer
Prop firms do not all calculate drawdown the same way. Before trading, identify the daily loss limit, the overall maximum loss, whether they are measured from balance or equity, when any daily limit resets, and whether the limit is static or trailing. Then size each trade so its planned loss fits comfortably inside the rules—not right up against them.
Balance, equity, drawdown and breach level
These terms are related, but they are not interchangeable:
- Balance: account value after closed trades and booked account transactions. It does not normally include the live profit or loss on open positions.
- Equity: balance adjusted for the floating profit or loss of open positions and, depending on the platform and rule definition, commissions, swaps and other charges.
- Daily loss limit: a limit on how far the account may fall during a defined trading day. The reference point and reset time depend on the programme.
- Maximum loss / overall drawdown: the account’s overall loss boundary. It may be fixed from initial capital or trail a balance or equity reference.
- Breach level: the minimum permitted balance or equity under the rule. Some firms can record a breach intraday even if the account recovers later.
Always confirm what value is monitored. A trade can remain open and still affect equity-based loss rules; waiting for the trade to close does not necessarily avoid a breach.
How daily drawdown works
A daily limit restricts losses over the firm's defined daily period. The calculation can use an opening balance, opening equity or another specified reference point. The rule also defines when the day resets—such as a named server time or time zone—and what happens to the limit after profit or loss.
One common form of calculation is:
Daily breach level = defined daily reference value − allowed daily loss amount
The formula is only a framework. Some programmes calculate the loss amount as a percentage of initial capital, while others apply the percentage to a different baseline. Some limits are based on equity and include open-position losses, commissions and swaps. Read the actual rule rather than assuming every “3% daily loss” label means the same thing.
For an example of how a specific firm documents its calculation, see FTMO’s published Trading Objectives. That page describes its own programmes; it is not a universal rule for all prop firms and can change over time.
Static maximum loss versus trailing drawdown
An overall loss limit can behave in several ways. The exact programme terms determine which applies.
| Rule type | How the floor behaves | What to watch |
|---|---|---|
| Static maximum loss | The floor is set from the initial account balance or capital and does not rise when profits are made. | Check which starting value is used and whether the rule is tested against equity or balance. |
| End-of-day trailing | The floor can move up based on a defined end-of-day balance or equity high; it may not move down after a losing day. | Read the reset time and whether open P/L is included in the trailing reference. |
| Intraday trailing | The floor follows a specified high-water mark during the trading session or in real time. | A pullback from a new high can breach the rule even if the account remains above its original starting balance. |
Do not assume that a “maximum loss” rule is static, or that a trailing limit tracks closed balance rather than equity. Those details can materially change the available buffer after a profitable trade.
Worked example: hypothetical $100,000 account
The numbers below are for arithmetic practice only. They are not a recommendation, a promise of eligibility, or a claim about any particular firm’s current rules.
| Item | Hypothetical rule | Calculation |
|---|---|---|
| Initial account size | $100,000 | Starting reference |
| Daily loss amount | 3% of initial capital | $100,000 × 0.03 = $3,000 |
| Daily breach level | Assume the defined day-opening balance is $102,000 and the $3,000 amount is deducted | $102,000 − $3,000 = $99,000 |
| Static overall loss amount | 10% of initial capital | $100,000 × 0.10 = $10,000 |
| Static overall breach level | Initial capital less the stated loss amount | $100,000 − $10,000 = $90,000 |
This example deliberately uses a particular way of defining the daily loss amount. A different programme may calculate the daily floor differently, use another percentage, or apply a trailing overall-loss rule. Charges and floating losses may also count. Your firm’s dashboard and current rulebook take precedence over this example.
How to calculate position size
Lot size should follow the cash amount you are prepared to risk and the distance to the stop-loss—not a fixed lot size chosen before the setup is known.
Cash risk budget = chosen account reference × risk percentage
Position size = cash risk budget ÷ (stop distance × value per unit of price movement per lot)
For forex, traders often express the stop distance in pips and use the pip value per lot. The pip value depends on the currency pair, contract specification and account currency. For indices, metals, futures or crypto CFDs, use the instrument’s relevant point/tick value and contract size instead.
Example: calculate, then round down
Suppose the account reference is $100,000 and a trader chooses a hypothetical 0.25% risk budget. The cash risk budget is $100,000 × 0.0025 = $250.
Assume—only for illustration—that the stop is 40 pips away and one standard lot on the selected symbol has a pip value of $10 per pip in the account currency. The calculated size is:
This is a mathematical illustration, not a universal lot-size answer. Confirm pip/tick value, contract size, lot increments and account-currency conversion in your platform or broker calculator. Account for expected commission and slippage, and round down where needed so the planned loss remains within the budget.
Do not size from the account balance alone
- Measure the actual stop distance from the intended entry price to the stop-loss.
- Use the correct pip, point or tick value for the instrument and account currency.
- Include commissions, spread, swaps where relevant and a realistic slippage allowance.
- Reduce size if the stop must be wider; do not move the stop closer solely to justify a larger position.
- Consider all simultaneous positions, correlated instruments and exposure that could move together.
Build a practical daily risk plan
A risk plan connects the maximum account limits with the risk of each individual trade. It should make it difficult for a few ordinary losses, open positions or an unexpected execution cost to push equity close to a rule boundary.
- Write down the rule: note the daily reference value, daily breach level, overall breach level, reset time and whether each is tested on balance or equity.
- Set a smaller internal stop: choose a personal daily stop below the firm's maximum. This is a safety buffer, not permission to use the full firm limit.
- Set cash risk before entry: calculate the position from the stop distance and the selected risk budget. Do not increase risk to recover a loss or hit a target faster.
- Count open risk: include floating losses and planned losses on other positions. Several trades on the same or correlated markets can worsen together.
- Recheck after events: after a position closes, before the daily reset, and before holding through a rollover, news release or weekend, check the current rule and remaining buffer.
- Stop when your plan says stop: do not continue trading because the firm’s limit has not been breached yet.
There is no universal “safe” risk percentage. A suitable size depends on the account rules, strategy behaviour, stop distance, expected number of simultaneous positions and the trader’s ability to follow the plan. Backtests and hypothetical examples cannot guarantee live results.
Common mistakes that can cause a breach
- Confusing daily and overall limits: passing one check does not mean you have room under the other.
- Looking at balance only: the rule may monitor equity and include floating losses or trading costs.
- Assuming the reset time: the reset may follow the firm’s server time, a named time zone or a session boundary.
- Ignoring trailing behaviour: a rising floor can reduce the buffer after a new high.
- Using fixed lots on every setup: different stop distances produce different cash risk.
- Adding correlated positions: several separate orders may act like one large combined exposure.
- Chasing losses or a target: changing size under pressure can undermine the risk plan.
- Relying on an indicator to police every rule: check what the software actually monitors; never assume it captures all firm-specific limits and exceptions.
Before your next prop firm trade
- I have read the current rules for the exact account, programme and phase.
- I know the daily reset time and the reference used to calculate the loss limit.
- I know whether the daily and overall limits apply to balance, equity or another metric.
- I know whether floating P/L, commissions, swaps and fees count toward a breach.
- I understand whether maximum loss is static, end-of-day trailing or intraday trailing.
- I have calculated the cash risk from the actual stop distance and correct instrument value.
- I have included open positions, related exposure and a reasonable cost/slippage buffer.
- I have an internal stop for the day and will stop when it is reached.
How a trading tool fits into risk management
PROP FIRM KILLER by WSWFX is a MetaTrader 4/5 indicator and Expert Advisor product. Any trading tool should be evaluated against the rules of your specific account and the way you actually trade. Verify which risk controls the supplied version performs automatically, which values it displays, and which checks remain your responsibility. Never assume a product enforces a prop firm’s entire rulebook unless its documentation confirms the exact behaviour and you have tested it.
Our MT4/MT5 guide explains platform compatibility, indicator versus EA behaviour, backtest quality and how to assess “no repaint” claims.
Read the MT4/MT5 guide ↗ Review PROP FIRM KILLER by WSWFX ↗Frequently asked questions
Are all prop firm daily drawdown rules calculated the same way?
No. Firms and programmes can use different reference values, reset times, percentages and balance/equity definitions. Read the current terms for your exact account.
Can an open trade breach a daily loss limit before it is closed?
Yes, if the programme checks equity or otherwise includes floating losses. Never assume only closed trades count.
Is a 0.25% or 0.5% risk per trade always safe?
No percentage is safe for every strategy or programme. Even small risks can accumulate across correlated or simultaneous positions, and actual losses can exceed a plan because of slippage or gaps.
Does a fixed lot size mean fixed risk?
No. With the same lot size, a wider stop usually risks more cash than a tighter stop. Changes in instrument value, conversion rates, spread and execution can also affect the result.
What is the difference between static and trailing maximum loss?
A static floor is fixed from a defined starting reference. A trailing floor can rise as the account or its defined high-water mark rises. The trailing calculation and whether it uses balance or equity vary by programme.
Can a trading indicator guarantee compliance with prop firm rules?
No. Software features vary, rules can change and execution conditions matter. Confirm what your actual product version monitors and verify the firm's current terms yourself.
Official rule reference and further reading
- FTMO: Trading Objectives — an example of how one provider documents daily loss and maximum-loss calculations. Always check the exact programme and current terms.
- MetaTrader 5 platform — platform information and trading tools.
- PROP FIRM KILLER by WSWFX: MT4/MT5 indicator selection guide — compatibility, testing and product-evaluation checklist.
Risk disclosure: This article is for general educational information, not financial, investment, tax or legal advice. Trading leveraged instruments involves substantial risk and you may lose money. Hypothetical calculations are illustrative and do not represent any specific firm’s current rules unless explicitly stated. Rules, fees, products and programmes can change; always check the current official terms and independently verify calculations before trading.