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The Arithmetic of a Challengewhat the fee has to buy before any of this is worth doing

Evidence: ModerateProfessionalProp firm · Expectancy

Before a single trade, a challenge is a purchase. You pay a fee for the option to trade someone else's capital under constraints, and whether that is a good purchase is a calculation you can do in advance.

The calculation needs three numbers: the fee, your honest probability of passing, and what you expect to earn from a funded account before it ends. Two of those three are estimates and one of them is usually wildly optimistic.

This page is not an argument against challenges. It is the arithmetic, so the decision is made with numbers rather than with hope.

Nothing here states any firm's rules. Firms differ and they change their terms — read your own rulebook and write the numbers into the bot. Every page assumes you have done that.

Applies to
The decision to buy an evaluation at all
Timeframe
Any — the decision is made before a timeframe is chosen
The calculation
expected value = P(pass) × expected funded earnings − fee, repeated across retries
The hard input
P(pass) — no firm publishes it and your own estimate will be too high
Tools
Your own strategy's return distribution · the firm's target, floor and time limit · the fee

Valid setup

PF-05 · THE ARITHMETIC OF A CHALLENGE — ONE RESAMPLED PATH one of thousands of sequences built from your own trade record · the estimate is what fraction of them reach the target first SIMULATION 92.3 95.2 98.2 101.1 104.0 107.0 109.9 the corridor every simulated path has to stay inside TARGET — reached, in this path start closest approach to the floor in this path FLOOR — the paths that touch this are the ones that decide P(pass) 1 2 3 108.0 100.0 97.0 94.0 ① This path came close to the floor and survived ② Thousands of others do not — that ratio is P(pass) ③ It must be simulated at the size you will actually trade ④ Target reached here, on this sequence ⑤ Multiply by expected funded earnings, subtract the fee ⑥ No trade record means no estimate is possible

Exact rules

Entry

  • Estimate P(pass) by simulation, not by feeling: take your strategy's own historical trade outcomes, resample them into many sequences, and count how many reach the target before the floor at your chosen size.
  • Do that at the exact size you intend to trade. Halving the size changes the answer in both directions — less chance of breaching, less chance of reaching the target in time.
  • Include the retry cost. Most people who pass have paid for more than one attempt, and the honest calculation is over the total spent.
  • If you have no trade record to resample, you cannot estimate P(pass), and neither can anyone else. That is the answer, and it is a useful one.

Stop loss

  • Treat the fee as a full loss at risk. It is spent whether you pass or not.
  • Cap total spend on evaluation fees the way you would cap trading risk — a fixed fraction of what you can lose, decided in advance.
  • Repeated retries after failures is the same behaviour as increasing size after losses, in a different costume, and it should be governed by a written rule.

Take profit / exit

  • Expected funded earnings must account for the account ending. Funded accounts do not run forever and the calculation has to include how long yours realistically lasts.
  • Compare the result honestly against trading the fee as your own capital. Sometimes the challenge wins that comparison, because the leverage on offer is genuinely large — and sometimes it does not.
  • Do the calculation once, write down the answer, and revisit it only when one of the inputs actually changes.

Build The Arithmetic of a Challenge

Reading this page is free and always will be. Taking it is what costs — the complete MQL5 for the rules above, yours to keep, permanently. Five of them cost $10 and they never expire.

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Trading carries risk and most retail accounts lose money. Nothing on this page is financial advice or a recommendation to trade. The chart is an illustration of the rules on constructed candles — it is not a record of a trade and not a backtest.