Position size for futures trading is calculated from three inputs: the dollar amount you are willing to risk on the trade, the tick distance from your entry to your stop loss, and the dollar value per tick of the contract you are trading. The formula is: contracts = dollars at risk divided by (stop distance in ticks times tick value). For NQ at $5 per tick with a 20-tick stop, risking $200 per trade means 200 divided by (20 × 5) = 2 contracts. Most prop firm traders blow accounts because they skip this math and size based on feel instead of numbers.
Most futures traders spend 80% of their learning time on entries and 20% on everything else. This is backwards. Entry timing matters but it is not what makes or breaks your account. Position sizing is. A great entry with bad sizing blows accounts. A mediocre entry with good sizing survives and compounds. The math is not complicated — most of what follows is arithmetic you learned in school — but almost no retail trader actually does it before every trade, and that gap is why most retail traders fail.
This guide walks through the exact math, with worked examples on the most common futures contracts (NQ, ES, MNQ, MES, CL, GC), and shows how position sizing specifically interacts with prop firm drawdown rules to keep you alive during evaluations. If you are about to take your first prop firm evaluation and you have never calculated position size explicitly, read this guide before your first trade. It is the difference between passing in 15 days and blowing up on day 3.
This is the maximum dollar amount you are willing to lose on a single trade if the stop hits. It is not "the max loss if everything goes wrong in the entire world." It is the max loss if the stop does what stops are supposed to do — take you out of the trade.
For prop firm traders, the right way to calculate this is as a percentage of your drawdown buffer, not your account balance. On a $50K Apex account with a $2,500 trailing drawdown, your real capital at risk is $2,500 (that is the amount that can actually be lost before the account dies). Risking 1% of $2,500 per trade means risking $25. Risking 2% means $50. These numbers sound tiny but they are correct given what you can actually afford to lose.
Compare this to the common mistake of risking 1% of the account balance: 1% of $50,000 is $500. At $500 per trade, you can only afford 5 stops before the drawdown is gone. That is one bad session. The "1% rule" that works for retail cash accounts is far too aggressive for prop firm accounts because the real capital at risk is a small fraction of the account size.
This is the number of ticks between your planned entry and your planned stop loss. You should know this number before you enter the trade, not discover it after. If you are trading a setup that has "adaptive" stops that you figure out in the moment, you cannot size the position correctly — you are effectively guessing at your dollar risk.
Typical stop distances by trading style:
This is the dollar value of one tick of movement on the specific contract you are trading. Different futures contracts have very different tick values, and this is the place where traders who switch contracts most commonly miscalculate their sizing.
| Contract | Tick size | Tick value | Point value |
|---|---|---|---|
| NQ (E-mini NASDAQ) | 0.25 | $5.00 | $20 |
| MNQ (Micro NASDAQ) | 0.25 | $0.50 | $2 |
| ES (E-mini S&P 500) | 0.25 | $12.50 | $50 |
| MES (Micro S&P) | 0.25 | $1.25 | $5 |
| RTY (E-mini Russell 2000) | 0.10 | $5.00 | $50 |
| M2K (Micro Russell) | 0.10 | $0.50 | $5 |
| YM (E-mini Dow) | 1.00 | $5.00 | $5 |
| MYM (Micro Dow) | 1.00 | $0.50 | $0.50 |
| CL (Crude Oil) | 0.01 | $10.00 | $1,000 |
| GC (Gold) | 0.10 | $10.00 | $100 |
Notice the huge range: micro contracts (MNQ, MES, MYM, M2K) have tick values of $0.50 to $1.25, while standard contracts (NQ, ES, RTY) have tick values of $5 to $12.50, and commodity contracts (CL, GC) have tick values of $10 each. A trader who mentally sizes "2 contracts" without thinking about which contract they are trading is risking 10 to 25 times as much dollar capital when they accidentally trade NQ instead of MNQ.
Contracts = Dollars at Risk ÷ (Stop Distance in Ticks × Tick Value)
That is it. Three inputs, one calculation, always rounded down to a whole number of contracts (you cannot trade fractional contracts).
Contracts = 50 ÷ (10 × 5) = 50 ÷ 50 = 1 contract
One contract is the correct size for a 10-tick NQ scalp risking $50 on a 50K Apex account. If you tried to trade 2 contracts, you would be risking $100 per trade — 4% of your drawdown — which is too aggressive. After just 5 losing trades you would be halfway to blowing the account.
Contracts = 67.50 ÷ (30 × 5) = 67.50 ÷ 150 = 0.45 contracts
You cannot trade 0.45 contracts. Rounding down gives you 0 — the trade is too big for your risk tolerance on this account. Your options are: reduce the stop distance (take a tighter setup), increase your risk percentage (accept more aggressive sizing), or switch to micro contracts (MNQ instead of NQ).
Switching to MNQ:
Contracts = 67.50 ÷ (30 × 0.50) = 67.50 ÷ 15 = 4.5 contracts, round to 4
4 MNQ contracts is the right size for this setup. This is exactly why micro contracts exist — they let you take the same trade setups with appropriate risk on smaller accounts.
Contracts = 60 ÷ (6 × 12.50) = 60 ÷ 75 = 0.8 contracts
Round down to 0. The trade does not fit within your risk budget. ES's $12.50 tick value is too large for $60 risk on such a tight stop. Solution: switch to MES (tick value $1.25) and you can trade 8 contracts. Or accept a slightly higher dollar risk and take 1 ES contract at $75 risk per trade instead of $60. The math tells you which trade is actually available given your constraints.
Contracts = 50 ÷ (5 × 10) = 50 ÷ 50 = 1 contract
One CL contract fits. This shows how commodity contracts with high tick values ($10) still work for scalpers as long as the stop is tight. If you tried to take a 20-tick CL swing on the same account, the math would require $200 of risk (20 × $10 × 1 contract), which is far too much.
The examples above assume your drawdown buffer is full — that is, you just started the evaluation and have the entire $2,500 (or $3,000, or $4,500) to work with. But during the evaluation, your actual buffer shrinks and grows based on your P&L. A good position sizing system scales down when the buffer is thin and scales up when the buffer is healthy.
Recalculate your dollars-at-risk based on your current buffer, not your original buffer. If your original buffer was $2,500 and you are now sitting on $1,500 of remaining buffer (because you lost $1,000 over the last few sessions), your new 2% risk is 2% of $1,500 = $30, not $50.
| Remaining buffer | Risk % | Dollars at risk | NQ 10-tick contracts |
|---|---|---|---|
| $2,500 (full) | 2% | $50 | 1 NQ |
| $2,000 | 2% | $40 | Less than 1 NQ — switch to MNQ |
| $1,500 | 2% | $30 | MNQ only, 6 contracts |
| $1,000 | 2% | $20 | MNQ only, 4 contracts |
| $500 | 2% | $10 | Stop trading — buffer too thin |
This is the single most important insight in position sizing: your size should shrink as your buffer shrinks. Traders who keep the same size regardless of buffer state blow through the account because they are effectively risking a larger percentage of their real capital with every losing trade.
The single most common mistake. A trader takes "2 contracts because that feels right for this trade" with no calculation of what 2 contracts actually costs on the current setup. Sometimes they get lucky with small stops and survive. Sometimes they get unlucky with big stops and blow through the drawdown in one trade. Over many trades, feel-based sizing is mathematically equivalent to randomized sizing, which is equivalent to flipping coins with your drawdown buffer.
A trader feels "very confident" about a setup and sizes up from 1 to 3 contracts. The setup fails like 40% of setups do. Now the loss is 3x normal on a losing trade. Over time, conviction-based sizing loses money because your conviction is not well-calibrated to actual win probabilities. Nobody's is. The market does not care how confident you are. Size the same regardless of how sure you feel, and let the math determine outcomes.
Three wins in a row. Trader feels unstoppable. Sizes up from 1 to 4 contracts. The fourth trade is a normal-probability trade but now it is losing 4x the normal amount. One loss wipes out the previous three wins. This is called "risk drift" and it is one of the most reliable ways to give back profits. The fix: never change size mid-evaluation regardless of how many wins or losses you have had.
After two losses, a trader drops from 2 contracts to 1 to "reduce risk." The next 5 trades are winners. But they only won 1 contract each instead of 2, so the wins do not cover the earlier losses. The math worked against them because fear-based sizing cuts your upside during exactly the periods you need upside most. The fix: same as mistake 3 — never change size mid-session.
On micro contracts especially, commissions and exchange fees can be a meaningful percentage of the tick value. A $0.50 MNQ tick with $1 round-trip commission per contract means you need to clear 2 ticks of profit before you break even on each contract. Traders who do not account for this think their setups work when they do not. Always include commissions in your position sizing math if you are trading micros. On standard contracts (NQ, ES) the commission impact is smaller relative to the tick value but still real.
The calculation above looks like work. Nobody wants to do arithmetic before every trade. The practical solution is one of three approaches.
Before you start trading, work out the correct size for every setup you might take based on your current drawdown buffer. For example: "On a 10-tick NQ scalp, I take 1 contract. On a 20-tick NQ setup, I take micros only. On an ES 8-tick scalp, I take 1 contract at $100 risk." Tape this list next to your monitor. You never have to do math during the session — you just look at your list.
Many traders use a simple spreadsheet or web-based calculator where they input the dollars-at-risk and stop distance and get the contract count back. This works but requires you to stop and calculate before every trade, which can be slow during fast-moving markets.
The best approach is to use a tool that automatically calculates the correct position size based on your current drawdown buffer and intended stop. Tradecovex's per-account risk management does exactly this — you configure your risk rules once (e.g. "2% of current drawdown buffer, always") and the tool enforces the correct size on every order. You never have to do math during the session, and you cannot accidentally oversize because the system stops you.
This is specifically why integrated copier plus risk management tools exist. Manual sizing is too error-prone during fast-moving sessions. Automated sizing based on current account state is the only reliable solution for traders running multiple prop firm accounts under 2026 rules.
Position sizing is arithmetic, not strategy. The formula is the same for every trade: dollars at risk divided by stop distance in ticks times tick value. The only inputs that change are your current drawdown buffer (which determines your dollar risk) and the specific setup (which determines the stop distance).
Traders who do this math on every trade consistently survive evaluations because they never take positions that are too big for the account. Traders who skip it consistently blow up because sooner or later they take one trade that is 5 to 10 times oversized for the buffer, hit the stop, and lose most of the drawdown on one trade.
The good news: once you automate or pre-calculate your sizing, this stops being a conscious decision. It becomes part of the infrastructure that keeps you alive. The 30 minutes you spend setting up your sizing rules is probably the highest-ROI 30 minutes in your entire prop firm career.