Ask ten traders how much they risk per trade and you'll get ten answers, most of them some version of “it depends on the setup.” That answer feels like discretion. More often it's just the absence of a rule — and the absence of a rule is what turns one bad week into an account that never recovers. The question has a boring, checkable answer, and the arithmetic behind it takes about two minutes.
Start with a percentage, not a dollar amount
The standard answer is fixed-fractional sizing: risk a fixed percentage of your account on each trade, commonly somewhere between 0.5% and 2%. The percentage matters less than the fact that it's fixed. A fixed dollar risk — “I always risk $200” — quietly gets more dangerous as the account shrinks and more timid as it grows, which is exactly backwards. A fixed percentage does the opposite automatically: it scales down after losses, when you can least afford another full-size hit, and scales up after gains, when the money at risk is profit rather than original capital.
The reason to keep that percentage small is not caution for its own sake. It's that losing streaks are longer than intuition suggests. A strategy that wins 50% of the time will still throw seven losses in a row reasonably often across a few hundred trades. At 1% risk, that streak costs you about 7% and you keep trading. At 5%, it costs you about a third of the account, and now you need a 50% gain just to get back to flat. That asymmetry — the fact that recovering from a drawdown takes more than the drawdown itself — is the whole argument, and it's what risk of ruin formalizes.
Percentage of what balance?
Here's the step most sizing advice skips. “1% of your account” is only meaningful if you know what your account balance actually is — and a surprising number of traders don't, because their journal computes balance as starting capital plus cumulative P&L and never accounts for deposits or withdrawals. If that figure has drifted from your broker's, every position size you derive from it is wrong by the same margin, in the same direction, on every trade. Worth reconciling that number before you build a sizing rule on top of it.
Turning a percentage into contracts
A percentage is a dollar figure; a position is a contract count. Bridging the two is where futures traders lose people, because the conversion runs through tick value, not price.
The chain is: your risk budget in dollars, divided by the dollar risk of one contract, rounded down. The dollar risk of one contract is your stop distance measured in ticks, multiplied by that instrument's tick value. On a $25,000 account risking 1%, your budget is $250. If you're trading MES with a 20-point stop, that's 80 ticks at $1.25 per tick, or $100 of risk per contract — so two contracts, with change left over. The same 20-point stop on full-size ES is $1,000 per contract, which doesn't fit the budget at all. Same trade idea, same stop, entirely different answer, purely because of contract specification.
This is arithmetic you should never be doing in your head mid-session. Our free position size calculator has the tick values for ES, MES, NQ, MNQ, RTY, CL, GC and the rest built in — enter your balance, your risk percentage, and your stop distance, and it gives you the contract count directly.
Two details that trip people up. Round down, always — rounding 2.4 contracts up to 3 silently turns a 1% rule into a 1.25% rule. And size off your actual stop, the one your invalidation level implies, not a stop reverse-engineered to justify the contract count you wanted. Widening a stop to fit a bigger position is the most common way a sizing rule gets broken while appearing to be followed.
If you trade a funded account, the math has a ceiling
Prop and evaluation accounts change the problem. The binding constraint usually isn't ruin — it's a drawdown rule that ends your account long before your capital runs out. A $50,000 evaluation with a $2,000 trailing drawdown gives you 4% of headroom, total. A 1% risk rule sounds conservative right up until you notice it allows four consecutive losses to breach the account entirely.
Under a rule like that, the right risk figure is derived from the firm's limit, not from a generic percentage. Ask how many consecutive losses you want to survive, then divide your available drawdown by that number. Want to survive eight straight? Risk a quarter of a percent. The daily loss limit constrains you the same way from the other direction — and watch out for what “daily” means to your firm, because a futures session doesn't start at midnight. A position opened Sunday evening belongs to Monday's trading day, which is its own source of confusion when you're counting a day's losses against a limit.
ExpectancyIQ stores those constraints per account — drawdown rule, daily loss limit, profit target, max loss — and evaluates every imported trade against them, so a breach shows up as a fact rather than a surprise. For the forward-looking version of the question, the risk simulator bootstraps your own R-multiple history to estimate the probability of hitting your target before you hit your drawdown limit, at a given size. That's the number an evaluation account actually needs answered.
The Kelly temptation
Sooner or later someone will point you at the Kelly criterion, which computes a mathematically optimal fraction from your win rate and payoff ratio. It is genuinely correct — under assumptions traders can't meet. Kelly assumes you know your true edge exactly. You don't; you have an estimate from a finite sample, and a small sample can be off by a lot. Overestimate your edge and full Kelly sizes aggressively enough to be ruinous. Traders who use it at all use a fraction of it — half or quarter Kelly — which usually lands back in the same 0.5–2% neighborhood the simple rule started at.
The failure mode isn't choosing wrong — it's drifting
Most traders don't blow up because they picked 1.5% instead of 1%. They blow up because the number moved without them noticing. Size creeps up after a good run, when conviction is highest and four wins in a row feel like evidence rather than variance. Or it doubles after a loss, chasing it back. Both are invisible in the moment and obvious in the data.
Which is the practical reason to track risk per trade in a journal at all, rather than just deciding on a rule and trusting yourself to follow it. Recorded as R-multiples — each trade's result expressed in units of the risk you took on it — position sizing stops being a policy you intended to follow and becomes something you can see. A run of trades where planned risk quietly went from 1R to 2.5R shows up immediately on a chart, and not at all in your memory.
A rule you can actually check
- Pick a fixed percentage, small enough that eight consecutive losses would be survivable and uninteresting.
- If you're on a funded account, derive it from the firm's drawdown headroom instead — that limit binds first.
- Convert to contracts through tick value, off your real invalidation stop, rounding down.
- Log the risk you actually took on every trade, and review it as a series — the drift is the thing worth catching, not any single trade.
Want to see whether your own risk per trade has been holding steady? Import your trade history into ExpectancyIQ for free and check your R-multiples against the rule you thought you were following.