Futures position size calculator
How many contracts your stop and your risk actually allow, and what taking one more would really cost.
- Risk budget
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- This stop costs, per contract
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- Exact size the maths gives
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- Risk at this size
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- Stop in ticks
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- Stop in points
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What to put in the first box
On an account that is yours, the balance. On an evaluation or funded account, not the balance: put in the distance between where you are and the floor that ends the account. A $50,000 evaluation with the floor at $47,500 has $2,500 of room, and sizing 1% of $50,000 is really 20% of the number that can actually end you.
That is why the field says risk base rather than account. The arithmetic above does not care which one you typed, and it has no way of knowing, so the choice is the part you have to get right. The guide to sizing against a drawdown limit works through both shapes of floor and what a trailing one does to the number.
Round down, always
The arithmetic rarely lands on a whole number. Wanting 2.4 contracts and taking 3 is not a small liberty: it is a 25% risk overrun on every trade, taken quietly, and every loss in the session costs a quarter more than the one you planned. The calculator prices that explicitly rather than leaving it as a rounding detail, because it is the single most common way a plan on paper becomes a different plan in practice.
When the answer is zero
Sometimes one contract already risks more than the budget allows. That is not a calculator failure, it is the honest answer, and it has exactly three fixes: a smaller contract, a tighter stop, or a larger account. Trading it anyway is a fourth option that is really just a decision to run a different risk than the one you chose.
What percentage is right
This page will not tell you. What it will do is show you the consequences: pair it with the risk of ruin calculator and watch what happens to the probability of a blown account as risk per trade climbs, holding your edge constant. The number that matters is not the one that feels brave, it is the one that survives a losing streak you will certainly have.
Your own numbers beat any calculator. Drop a NinjaTrader export on the Trade Lab and it works these figures out from the trades you actually took. It reads the file in your browser and nothing uploads.