The 1% Rule in Trading: How Much to Risk Per Trade

What the 1% rule actually means

The 1% rule says you should never risk more than 1% of your account balance on a single trade. Not 1% of your position size. Not 1% of your buying power. 1% of the money you'd actually lose if your stop loss gets hit.

If your account is $10,000, that means your maximum acceptable loss on any one trade is $100. Your position size then gets built backward from that number: entry price, stop loss distance, and the size that makes those two numbers line up so the loss equals $100, not a cent more.

This is the single most misunderstood rule in retail trading. Most beginners hear "risk 1%" and think it means something vague about being careful. It's not vague. It's an exact dollar figure you calculate before every trade, and it doesn't move once you're in the position.

Why the number is 1% and not 5%, or 10%

The 1% rule exists because of how losing streaks compound. Every strategy, even a genuinely good one, goes through stretches of consecutive losses. That's not a sign something is broken. It's just what a series of independent probabilistic outcomes looks like.

The problem is that the math of risk isn't a straight line. Risking 2% per trade instead of 1% doesn't just mean "twice the risk." A string of losses at 2% per trade erodes your account far faster than the same string at 1%, because each loss is taken from an already-smaller balance, and the percentage gain required to recover gets steeper the deeper the hole gets. A 20% drawdown needs a 25% gain to recover. A 50% drawdown needs a 100% gain. That asymmetry is brutal, and it's the entire reason position sizing discipline matters more than which strategy you use.

At 1% risk per trade, even ten losses in a row (rare, but it happens) leaves you down roughly 10%, a setback, not a crisis. At 5% per trade, ten straight losses can wipe out well over half the account. The rule isn't about being timid. It's about staying solvent long enough for your actual edge to play out over a large enough sample of trades.

How to calculate it correctly

Three inputs, every time:

• Account balance: the real number in your account right now, not what it was last month.
• Risk percentage: 1%, or less if you're newer or the strategy is untested.
• Stop loss distance: the price difference between your entry and where you're proven wrong.

Risk amount is balance multiplied by risk percentage. Position size is risk amount divided by stop loss distance. That's it. If a $10,000 account risks 1% ($100) and the stop is $2 away from entry, the position size is 50 units. Not 5,000 units. Not "however much feels right." Fifty.

If you want to skip the arithmetic, the Risk/Reward Ratio Calculator does the entry/stop/target math for you, and pairs naturally with this rule since risk sizing and risk/reward are two halves of the same decision.

The mistakes that quietly break the rule

Moving the stop loss after entry. The moment you widen a stop because the trade is "about to turn around," the 1% you calculated is no longer accurate. You're now risking more than you decided, after you decided it, which defeats the entire purpose.

Confusing position size with risk. A bigger position isn't automatically more dangerous if the stop is proportionally tighter, and a small position isn't automatically safe if the stop is far away. The dollar amount at risk is what matters, not the number of units or lots.

Sizing up after a loss to "win it back." This is revenge trading wearing a math costume. The 1% rule has to apply identically whether your last trade won, lost, or you haven't traded today at all. The moment your risk percentage depends on your mood or your recent results, it's not a rule anymore.

Treating 1% as mandatory rather than a ceiling. For newer traders, or strategies without a real track record yet, 0.5% or even 0.25% is a reasonable starting point. The rule caps how much you can risk. It doesn't require you to use the full amount every time.

Is 1% always the right number

Not necessarily, but it's a sound default for a reason: it survives bad stretches without requiring you to be right about when the bad stretch will end. Some prop firm evaluations enforce tighter daily or per-trade limits than 1%, in which case their rules take priority over the general guideline. Traders with a long, verified track record sometimes size slightly larger. But if you're not certain which category you're in, 1% (or less) is the number that keeps you in the game long enough to find out.