Consistency Rule Calculator

The formulas

compliant when: best day ≤ rule × total profit
minimum total = best day ÷ rule
still to earn = max(0, best day ÷ rule − total)

The subtle part is the direction of the constraint. The rule does not limit what you may earn in a day going forward in any direct way; it limits what you may withdraw until your total profit is large enough that no single day dominates it. Every new profitable day helps twice, it raises the total and (unless it becomes the new best day) leaves the numerator alone.

A worked example

A funded trader under a 30% rule has $5,000 of total profit, $2,000 of it from one strong day. That day is 40% of the total, over the limit, so no payout yet. Minimum compliant total is 2,000 ÷ 0.30 = $6,666.67: the trader needs $1,666.67 of further profit, earned without any single new day exceeding the (growing) allowance. The calculator also shows the biggest single day you can currently afford: rule × total ÷ (1 − rule), computed against your future total, because a new best day raises both the numerator and the denominator at once.

That last formula deserves a sentence, because most traders get it wrong by checking a candidate day against today's total. If your total is T and tomorrow you make a day of size D, the check is D ≤ rule × (T + D), which solves to D ≤ rule × T ÷ (1 − rule). Under a 30% rule with $5,000 banked, the biggest safe new day is 0.3 × 5,000 ÷ 0.7 ≈ $2,142.86, noticeably more than the naive 30% × 5,000 = $1,500. A day of exactly that size becomes the new best day at exactly 30% of the new $7,142.86 total, and pulls every earlier day further inside the limit.

Works for any prop firm, at any percentage

Set the percentage and the calculator fits whatever your firm uses, so it covers Apex, TopStep, MyFundedFutures, Funding Pips, Alpha Futures, Take Profit Trader, Tradeify, Lucid, FundedNext and the rest, futures and forex alike. Published thresholds commonly land between 15% and 50%, with 30% and 40% the most frequently seen, but each firm sets its own and revises it from time to time, and programs within a single firm can differ, so the number in your current agreement is the one that counts. Enter that percentage, your best day and your running total, and the pass or fail is the same arithmetic wherever you trade.

Why firms impose it, and what it does to strategy

From the firm's side the rule screens out accounts whose entire profit is one lucky, oversized position, the profile most likely to blow up after funding. From the trader's side it quietly rewards exactly what the drawdown arithmetic rewards: many small, evenly sized days rather than a few heroic ones. If your strategy's returns are naturally lumpy, a few big days among many flat ones, a strict consistency rule is a real structural tax on you specifically, and it belongs in your firm comparison alongside the split and the drawdown type. Model the payout side with the profit split calculator and your pass odds with the profit target simulator.