Prop Firm Drawdown Calculator

The formulas

static floor = start × (1 − maxDD)
trailing floor = equity high − start × maxDD
max risk to survive N losses = 1 − (floor ÷ equity)^1/N

The daily floor is today's starting balance minus the daily loss allowance (daily% × account size, the convention most firms use; some compute it on the day's starting equity instead, which is why both inputs are separate). Your effective breach level is whichever floor is higher, that is the one you hit first on the way down, and the calculator flags which constraint is binding right now.

Survivable consecutive losses assume fixed-fractional sizing: each loss multiplies equity by (1 − risk), so the streak that breaches is the smallest n with equity × (1 − risk)ⁿ at or below the floor, n = ln(floor/equity) ÷ ln(1 − risk). The inverse of that formula answers the more useful planning question: given the streak length you want to survive, what is the biggest risk per trade you can afford?

A worked example

Assume you take an initial evaluation of $100,000 with a 10 percent maximum trailing drawdown and for some reason your trading has increased the value of your account from its peak of $104,000 down to $101,000. Static will place the floor at $90,000. Trailing will place it at 104,000 − 10,000 = $94,000. Your space is $7,000 (6.9% of your equity) or less than the 10 percent stated in the rules. At one percent fixed-fractional risk this space can absorb seven losses in succession (101,000 × 0.99⁷ ≈ $94,139, which is greater than the floor; eight losses will breach at approximately $93,197). To ensure that you survive ten straight losses you would be forced to reduce your risk to 1 − (94,000/101,000)^1/10 ≈ 0.72% on each trade. The math behind this is what creates trailing drawdown as the "silent killer" of funded accounts: profit given back to your broker works to move both sides of the equation against you.

And on most days none of that is your real constraint. With a 5% daily limit measured from a $101,000 day start, today's floor is $96,000, higher than the trailing floor, so the daily rule binds first. Traders who plan only around the max drawdown routinely fail on a daily breach with the "big" cushion untouched.

EOD versus intraday trailing, and comparing firms

How harsh a trailing rule is depends on when the floor updates. An intraday trailing floor follows your highest equity tick, so an unrealized peak you never banked still lifts it, the version the equity-high input above models. An end-of-day (EOD) trailing floor updates only on your closing balance each day, so intraday spikes do not count against you; it sits between static and intraday trailing in severity. Firms mix these freely: Apex, TopStep, Uprofit, Maven, Take Profit Trader and the rest each pick a combination of drawdown size, trailing type and reset time, which is exactly why a headline "$3,000 drawdown" or "6% drawdown" tells you almost nothing on its own. Put each firm's real numbers in here and compare the floor and the room they actually leave, not the percentage on the marketing page.

Why trailing rules punish scaling up

Under a static rule, early profit is a genuine cushion: every dollar earned is a dollar further from the floor. Under a trailing rule, early profit converts one-for-one into floor height until the limit locks (if it ever does). The practical consequence is that risk per trade should be at its smallest right after a new equity high under a trailing rule, exactly when overconfidence says to size up. Running your own numbers here after each trading day, thirty seconds of admin, keeps the floor visible while it moves. Pair it with the risk-of-ruin simulator to see how often your strategy's losing streaks reach the lengths that matter, and with the profit target calculator to see the pass probability these constraints leave you.