Futures
Futures position sizing, explained
The right number of contracts isn't a guess — it's a function of how much you're willing to risk, how many ticks away your stop is, and what that instrument's tick is worth.
The formula
Contracts = risk budget ÷ (stop distance in ticks × tick value)
Tick value is fixed per contract by the exchange — it's how many dollars one minimum price movement is worth, for one contract. Dividing your total risk budget by what your stop actually costs per contract tells you how many contracts you can take without risking more than you intended.
Worked example
You're willing to risk $300 on a trade. You're trading ES (tick value $12.50 per tick) with a stop 8 ticks away. Risk per contract = 8 × $12.50 = $100. Contracts = $300 ÷ $100 = 3 contracts. Trading MES instead (tick value $1.25) with the same 8-tick stop, risk per contract is $10, so the same $300 budget allows 30 contracts.
Why this matters more in futures than stocks
In stocks, share size scales smoothly with price. In futures, tick value is fixed and unrelated to the contract's price level, and jumps discretely between a full-size contract and its micro (often 10x apart) rather than scaling continuously — sizing off the wrong tick value, or off a full-size contract's tick value when actually trading the micro, is a common and costly mistake.
Track position size against your real risk, automatically
Fillbook flags an oversized position relative to your account's contract limit or your own risk budget — before it becomes a problem.
Start free →Frequently asked questions
Each futures contract has an exchange-specified tick size and point value that together determine tick value (tick size × point value). The futures P&L calculator lists these for 20+ common contracts including their micro versions.
Sizing off a fixed dollar risk budget per trade (rather than a fixed number of contracts) keeps risk consistent even as your stop distance varies from setup to setup — a tighter stop allows more contracts for the same dollar risk, a wider stop allows fewer.
Yes — for prop-firm accounts with contract limits set, Fillbook flags an oversized position relative to the limit before it becomes a problem; see the prop-firm trading journal page for the full account-rule feature set.
See how position sizing fits into the rest of futures-specific journaling on Futures Trading Journal — Fillbook.Calculate the P&L side with the Futures P&L Calculator — Fillbook.