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Prop firm consistency rules: the math, worked out

You hit the profit target. The account still didn't pass. Often the reason is a consistency rule. Here's how it works, with the math done for you.

Beginner guide · 8-minute read · Updated 2026-10-21

What a consistency rule is

A consistency rule limits how much of your total gain can come from one single day.

Firms use it to make sure a pass reflects steady trading, not one lucky, oversized day. The rule shows up in two places:

• In the evaluation, before you can pass.
• In the funded stage, before you can request a payout.

Not every firm has one. Some have it in one stage and not the other. The numbers below are made-up examples to show how the math works, not any real firm's terms. For the rest of the rule sheet, see prop firm rules explained.

The most common form: the best-day rule

It usually reads something like this:

The percent varies. 30%, 40% and 50% are all common examples. The idea is the same.

The one formula you need

That's it. Once you know your best day, you know the smallest total that passes the rule.

A worked example

Evaluation: $50,000 account, $3,000 profit target, 50% consistency rule.

On day 3, the account hit the $3,000 target. It still didn't pass. The best day ($1,800) was 58% of the total.

Using the formula: $1,800 ÷ 0.50 = $3,600. That's the real target once day 1 happened.

Why a big day can hurt more than help

It feels like a big day gets you closer. In money, it does. Under a consistency rule, it can also push the finish line further away.

At a 30% rule, a $2,500 day turns a $3,000 target into more than $8,000. That's a lot more time exposed to the daily limit and the trailing drawdown.

What a losing day does

Losing days make the ratio worse, because they shrink your total while your best day stays the same.

Example: best day $1,500, total $3,200. That's 47%, a pass at 50%. Now you lose $400. Total falls to $2,800. Now it's 54%, and you're below the target too. You need to make it back and then some.

The usual cause: size that changes

Most big days don't come from a better setup. They come from bigger size. Doubling the contracts on one trade doubles the day.

Keeping size fixed is the simplest way to keep days even. Our guide on how much to risk per trade explains a fixed-risk approach. In futures, size from the stop in dollars: the futures tick value calculator does the tick math.

In the funded stage: tied to payouts

In funded accounts, consistency rules usually apply to the gains since your last payout. Before a payout request, your best day may need to be under a set share of that period's total.

If it isn't, you might need to keep trading until the ratio fits. That means more days at risk before any payout. More in prop firm payouts explained.

Other forms you might see

• A daily profit cap. Gains above a set amount in one day don't count toward the target.
• A ratio to the average day. Your best day can't be more than a set multiple of your average day.
• A position-size consistency check. Your size can't jump far above your usual size.

Each one has the same goal: steady trading. Read the exact wording. "Best day" might mean the closing balance change, or the high point during the day.

A 1-minute check you can do daily

1. Write down your best day so far.
2. Divide it by the rule's percent. That's your real target.
3. Compare it with your current total.
4. If the real target is far above the stated one, size down. Don't chase it with a bigger day.

Common mistakes

• Celebrating a huge day on day 1. It often makes the rest of the evaluation longer.
• Trying to "fix" the ratio with one big trade. That makes a new, bigger best day.
• Forgetting the rule in the funded stage. It can delay payouts.
• Not knowing what counts as a "day." Some firms use a trading session that starts the evening before.

Try it today

1. Take your last 20 practice trades, grouped by day. See how to keep a trading journal.
2. Find your best day and your total.
3. Work out your best-day percent.
4. Would it pass a 50% rule? A 30% rule?
5. If not, check whether your best day came from bigger size. Write one sizing rule that would have kept it even.

Questions