Prop firm rules, decoded and computed

Prop-Firm Rules, Decoded.

A prop challenge isn't only a test of trading skill. It's a rulebook with barriers — and here's the math to run before you pay the fee.

Prop Firm Consistency Rules: Your Best Day Is the Problem.

A consistency rule caps how much of your total profit one day may represent — which means your proudest green day can silently lock your payout and hand you a debt: more profit you now owe on other days before you see a cent. Here's the arithmetic nobody prints (your best day × 3.33 under a 30% cap), four worked examples, and how to size days so the rule never notices you.

Prop Firms Without a Consistency Rule: We Read the Rulebooks.

Some prop firms genuinely publish no consistency rule — but the question hides three qualifiers most lists skip: which product, which stage, which payout path. The same brand can be rule-free in the challenge and capped at the payout desk. Here's what ten firms' own rulebooks say, quoted and linked, checked on one date — plus the five-minute check that beats any list, including this one.

Prop Firm Profit Target: A Trade Count, Not a Deadline.

An 8% target on a $100k challenge isn't 'make $8,000 this month.' At a real edge it's a specific number of trades — 64, in the worked example below — and knowing that number changes how you trade the whole evaluation. Includes the case where the honest answer is: no number exists.

Your Risk of Ruin Isn't Zero.

We computed real ruin probabilities with the same seeded engine behind our free calculator: a trader with a genuine edge, risking a 'standard' 2% per trade, has a 0.6% chance of losing half the account — and a 43% chance of touching the -10% line that fails a prop challenge. The curve doesn't climb. It explodes. Every number regenerates from one command.

Drawdown Recovery: The Math Is Brutal. The Plan Isn't.

Losing 50% means you need +100% just to get back — the asymmetry every trader learns too late. Here's the full recovery table from our public calculator, the three kinds of drawdown and how to tell which one you're in using your own journal, and the honest part: our own EA's backtest once sat 73% below its peak. We publish that number on purpose.

Trailing vs Static Drawdown: The Rule That Moves While You Trade

Two accounts, same drawdown percentage, completely different games: a static floor never moves, a trailing floor climbs behind every new equity peak — which means your best trading day can quietly shrink your cushion. Here's the arithmetic of both floors, the three firm-specific variants that decide everything, and why the dangerous moment is right after you've been winning.

How Much to Risk Per Trade: The Position Sizing Math That Decides Survival

There is an exact, mathematically optimal answer to 'how much should I risk per trade.' It's called the Kelly criterion — and betting it at full strength is one of the fastest ways to blow up a real account. Here's the formula, the trap inside it, and the fraction the pros actually use.