The maths of a challenge - 8% + 5%, daily DD, max DD

A prop challenge is not a competition for profit. It is a survival test. The 8% and 5% targets look harmless, but combined with a 5% daily DD and an 8-10% max DD they form a maths problem with a very narrow corridor. If you do not calculate this before you start, you are leaving it to randomness.

This lesson is a calculator, not motivation.

Lesson goal and what you will measure

By the end of this lesson you will be able to calculate:

• How many losses in a row end a challenge at a given risk % per trade.
• What maximum exposure you can carry under a daily DD.
• What combination of win rate / R:R is needed to make 8%.
• How the trailing DD versus static DD model changes the maths.

Measures: ruin table, risk calculator, expected number of trades to target.

Definitions that decide whether you pass

Daily Drawdown (daily DD): The maximum loss within a single day. The most important rule.

Variant A - balance-based (old FTMO, many firms still use it):

Max_daily_loss = Current_equity - Max(Start_of_day_balance, Start_of_day_equity) must not fall by 5%

So if you start the day with a balance of 100,000 and you have +2,000 floating open, your equity is 102,000. A fall to 97,000 is -5,000 from the start of the day = disqualification, even though you are still positive on balance.

Variant B - equity-based at midnight: More restrictive. The threshold is calculated every day at 00:00 server time.

Max Drawdown (max DD): The maximum slide from the account start. Two types:

• Static: 10% of the initial balance = always 90,000 on a 100k account. It does not rise.
• Trailing on balance (FundedNext, The5ers High Stakes): the max DD follows the highest balance reached, until it locks at the starting level. If you reached 108,000 on a 100k account with an 8% max DD, your threshold is now 100,000, not 92,000. That is considerably harder.

Without knowing the max DD type, you cannot calculate risk.

How many trades does it take to fail? Ruin maths at 8%

Let us assume a 100,000 account, 5,000 daily, 10,000 max static. You risk a constant R per trade.

Losses_to_daily = Daily_DD / (Risk_% * Capital)
Losses_to_max = Max_DD / (Risk_% * Capital)

At 1% per trade, 3 losses in a row plus commissions/spread are enough to bring you close to the daily. With 5 trades a day at 1% risk each, one bad streak ends the day.

That is why professionals in a challenge use 0.25% - 0.5% per setup.

How many trades to the 8% target?

Do you need 8R at R = 1% per trade? No. You need a net result.

A simple formula for the expected number of trades:

Expected_profit_per_trade = (Winrate * Avg_Win_R) - (Lossrate * Avg_Loss_R)
Number_of_trades = Target_R / Expected_profit_per_trade

Example: win rate 45%, avg win 2R, avg loss 1R.

EV = 0.45*2 - 0.55*1 = 0.9 - 0.55 = 0.35R per trade
Target = 8R (if 1R=1%)
Number of trades = 8 / 0.35 = 22.8 trades

At a 35% win rate and 2:1 R:R:

EV = 0.35*2 - 0.65*1 = 0.05R (!) -> 8 / 0.05 = 160 trades -> unrealistic in 30 days

Conclusion: to pass a challenge you need EV >0.25R, otherwise the number of trades grows exponentially and you fall into overtrading.

Table of required effectiveness:

The maths rewards higher R, not a higher win rate.

Daily DD and simultaneous positions

A beginner mistake: they calculate risk per trade but open 3 correlated positions (for example EURUSD, GBPUSD, AUDUSD long).

Portfolio_risk = Sum(Risks) * Correlation_coefficient
3 positions at 0.5% long on a weak USD = ~1.35% total risk, not 0.5%

With a 5% daily that is 25-30% of your buffer used up on a single macro decision.

Limit total exposure: max 1.0-1.5% across all open correlated positions.

When the plan says do not trade

• When you approach 50% of the daily DD on a given day - stop the day. Two more losses = fail.
• When you have 3 losses in a row at 1% risk - stop the session, not the day.
• When you did not calculate before the session: how many losses are left to the daily and to the max.
• When you have swing positions open and there are 3h left to server midnight, and floating equity of +4% raises your daily threshold for tomorrow.
• When the 8% target is “within reach” (7.5%) and a 2% risk tempts you to “finish it off” - this is the most common reason for failing at +7%.

The mistakes that cost the most

1. Raising risk as you approach the target. The maths of revenge: one 2% loss after a streak cancels out 4 wins at 0.5%. A trailing max DD locks you out for good.
2. Calculating DD from balance when the firm calculates it from equity. 70% of people fail the daily without knowing that floating profit raises the base.
3. Not accounting for commission and swap in R. If the stop loss is 20 pips and the spread is 2 pips, your real R is not 1% but 1.1%. Across 30 trades that is 3% of extra DD.
4. Stagnation and chasing the clock. You have 30 days, you make 0% for 20 days, then 8% in 5 days at 2.5% risk - variance kills you. Pace: 0.3-0.5% a day expected.

Measurable exercise

Build your own challenge calculator (spreadsheet)

Columns: Capital | Daily DD | Max DD | Risk/trade | Losses to daily | Losses to max | Phase 1 target (in R) | Historical win rate | Average R | EV | Est. number of trades | Realistic within the day limit?

Fill it in for 3 accounts: 25k, 50k, 100k for FTMO and FundedNext.

Extra task: simulate 100 sequences of 40 trades with a Monte Carlo method using your EV. Count the % of sequences that touch the daily DD before reaching 8R. Use:

import random
def simulate(p_win, avg_win_r, avg_loss_r, risk_pct, daily_dd_pct, target_r, n_sims=5000):
    wins = 0
    for _ in range(n_sims):
        bal = 0
        dd_day = 0
        # simplified logic
        # ...

If >30% of simulations touch the daily DD before the target -> halve your risk.

Test yourself

1. You have a 50k account, 5% equity-based daily, balance 51k, equity 52.5k at the start of the day. How much can you lose on equity without hitting the daily?
2. Why is a trailing max DD on high balance harder than a static one?
3. At a 50% win rate and 1.8 R:R, what is the EV and how many trades are needed for 8R?
4. You open 2 positions at 0.6% each, long EURUSD and GBPUSD. What is the real exposure?
5. You are up 7.2% in phase 1. There are 5 days left. Why is raising risk to 2% a mathematical mistake, not only a psychological one?

Frequently asked questions

What % per day should I make to pass 8% in 30 days? ~0.27% per day on average. But you need a buffer for losses. Aim for 0.4-0.6% of expected profit per day at 0.5% risk per setup, which leaves room for DD.

Is it better to take 20 small trades or 5 large ones? Small ones. The law of large numbers rewards low volatility. 5 large trades = high variance = an 80% chance that you touch the daily before you hit a streak.

Does commission count towards DD? Yes, always. DD is the balance/equity difference after all costs.

What if the firm has a 4% daily rather than 5%? A 1% difference is 20% less room. Cut your risk by 20% and your expected daily profit by the same. The maths does not change.

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Educational material. Not advice. Every firm has a different definition of DD - read the rulebook before every calculation.

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