Guide
How to size a futures position from your account value
If you trade your own money, the question is not what a firm allows. It is how much of your account one trade is allowed to cost. This guide shows the arithmetic step by step, so you can check any number a tool gives you.
Start with the share of your account one trade may cost
Pick the percentage of your current account value that one losing trade is allowed to cost, then multiply. Many traders choose a small single-digit percentage or less, but the right number depends on your account, your edge and how much loss you can tolerate, and nothing here is a recommendation of what it should be. Example: 1% of 20,000 dollars is a 200 dollar budget.
Price your stop in dollars per contract
Count the ticks between your entry and your stop, then multiply by the dollar value of one tick for that contract. A Micro E-mini Nasdaq contract (MNQ) moves in quarter-point ticks worth 0.50 dollars each, so a 40-tick stop costs 20 dollars per contract. Tick size and tick value are fixed for each contract: confirm them with your broker or the exchange.
Divide the budget by the cost per contract
Divide your dollar budget by the stop cost per contract and round down. 200 divided by 20 is 10 contracts. If the answer is below one, the trade does not fit your budget at that stop. A closer stop or a smaller contract is the only way to make it fit, or you skip the trade.
Check the margin, then use the smaller number
Your broker requires margin to hold a position, and the amount differs by broker, by contract and by whether you hold it during the day or overnight. Look up your broker's figure and decide what share of your account you are willing to tie up. The contracts you can hold are the smaller of what the risk budget allows and what your margin limit allows.
Why current account value, and what this leaves out
Your account changes with every trade, deposit and withdrawal. A budget set from the balance you started with becomes too large after a losing run and too small after a good one, so recalculate from the current value. A stop is not a guarantee: slippage, fast markets, gaps and overnight moves can make a trade lose more than the distance to your stop, and fees come on top. Treat the result as a ceiling for planning, not a prediction.
Work it out with your own numbers
Add an own-capital account in Fillbook to see sizing from your account value, using the margin you enter.
See how it worksCommon questions
That is a personal decision and this guide does not give a number. It depends on your account size, your edge, how many trades you take and how much loss you can tolerate. Fillbook lets you enter your own figure.
Yes. A wider stop costs more per contract, so the same dollar budget buys fewer contracts. That is why the stop is chosen first and the size follows from it.
Your broker publishes it and it can change. Fillbook does not supply margin figures: you enter your broker's day and overnight amounts yourself.
Futures trading involves substantial risk of loss and is not suitable for everyone. This guide is general education, not advice, and it cannot account for your situation. Read the full disclosures.
For the daily limit side of risk, read the guide to personal daily loss limits.Trading your own capital? See how Fillbook works for your own capital.