Position sizing with 1R: turn a stop into a contract count

How to set a fixed risk unit, convert any stop into a contract count for MES or MNQ, round down, include costs, and skip trades that do not fit.

Many new futures traders pick a contract count first and figure out the stop afterwards. That order is backwards, and it is how one bad day undoes a month of careful work. Sizing from a fixed risk unit flips it: decide what one loss may cost, find the stop the chart needs, and let a short formula give the contract count, using Micro E-mini S&P 500 (MES) and Micro E-mini Nasdaq-100 (MNQ) examples, including the case where the answer is zero.

What 1R means

1R is the amount of money you accept losing if a trade reaches its planned stop. It is set before the session, as a fixed percentage of the account, and it does not change because a setup looks especially good or because the last trade lost.

A percentage scales automatically: when the account shrinks, each loss shrinks with it, which slows a drawdown; when it grows, risk grows in proportion rather than in jumps driven by confidence.

Many self-directed traders use 0.25% to 1% per trade. There is no official number: pick one you could lose ten times in a row without abandoning the plan.

Illustrative example: a $25,000 account with 1R set at 0.5% has 1R = $125. Every trade in that account is planned so that a stop-out costs about $125, all-in.

The contract specs you need

The formula only needs two numbers per contract: the tick size and the dollar value of one tick. For the two equity micros used here, CME Group lists the following (check the current MES contract specs and the Micro E-mini equity overview before relying on them, as exchanges can amend contracts):

Micro E-mini specs used in this guide (source: cmegroup.com)

Contract	Multiplier	Tick size	Tick value	Value of 1 index point
MES (Micro E-mini S&P 500)	$5 x index	0.25 index points	$1.25	$5.00 (4 ticks)
MNQ (Micro E-mini Nasdaq-100)	$2 x index	0.25 index points	$0.50	$2.00 (4 ticks)

Both contracts tick in quarter points, so index points x 4 = ticks. The trap is the tick value: the same 10-point stop costs $50 per MES contract but $20 per MNQ contract, and MNQ stops are usually wider in points because the Nasdaq-100 tends to move more points per session. More contract detail is on the futures topic page.

The formula

Once 1R is fixed and the stop is placed where the setup is proven wrong, the contract count is:

contracts = floor( risk $ / (stop ticks x tick value) )

Always round down. Rounding up means every trade risks more than 1R, and over a losing streak those small overages compound into a much larger drawdown than you planned for. If the division gives 2.9, the answer is 2. If it gives 0.8, the answer is 0.

The steps, in order:

1. Write down 1R in dollars for today.
2. Choose the stop from the chart: below the level that invalidates the idea, not at a distance picked to allow more contracts.
3. Measure the stop in index points, then multiply by 4 to get ticks.
4. Multiply ticks by the tick value to get dollar risk per contract.
5. Add round-trip costs per contract (see below).
6. Divide 1R by the all-in risk per contract and round down.

Worked examples

MES

Illustrative example: account $25,000, 1R = $125. The setup needs a stop 8 index points from entry.

• Stop ticks: 8 x 4 = 32 ticks
• Risk per contract: 32 x $1.25 = $40.00
• Illustrative costs per contract: $1.50 round-trip commissions and fees plus 1 tick of slippage on the stop ($1.25) = $2.75
• All-in risk per contract: $42.75
• Contracts: $125 / $42.75 = 2.92, rounded down to 2

Planned loss at the stop is 2 x $42.75 = $85.50, about 0.68R. Trading slightly under 1R is the normal result of rounding down; trading over it is a mistake.

MNQ

Illustrative example: same account, same 1R of $125. The MNQ setup needs a 40-point stop.

• Stop ticks: 40 x 4 = 160 ticks
• Risk per contract: 160 x $0.50 = $80.00
• Illustrative costs per contract: $1.50 round-trip plus 2 ticks of slippage ($1.00) = $2.50
• All-in risk per contract: $82.50
• Contracts: $125 / $82.50 = 1.52, rounded down to 1

Planned loss is $82.50, about 0.66R. The wider point stop still fits because each MNQ point is worth less.

A quick sizing table

The table below uses the $125 1R from the examples and ignores costs to keep the arithmetic visible. With costs added, a row near a boundary can drop by one contract, so always run the full calculation for the actual trade.

Illustrative contracts per trade at 1R = $125, before costs

Stop (index points)	MES risk per contract	MES contracts	MNQ risk per contract	MNQ contracts
4	$20	6	$8	15
8	$40	3	$16	7
12	$60	2	$24	5
20	$100	1	$40	3
30	$150	0 (skip)	$60	2
60	$300	0 (skip)	$120	1
80	$400	0 (skip)	$160	0 (skip)

The count from the formula is a ceiling, not a target. Margin requirements, liquidity and your own comfort can all argue for fewer contracts, never more. Very tight stops produce large counts, which magnify costs and slippage.

When the stop is too wide for even one contract

If the formula returns zero, the trade does not fit your account at your risk unit. The decision rule is simple: skip the trade.

Illustrative example: a $5,000 account with 1R = 1% = $50. An MES setup needs a 12-point stop, which is 48 ticks x $1.25 = $60 per contract before costs. One contract would risk 1.2R or more. The answer is zero contracts.

Tightening the stop to make it fit puts the stop where the chart says the idea is still valid, so ordinary noise stops you out. Taking one contract anyway means this trade risks more than every other, usually on the volatile days when stops get hit. Switching to MNQ is legitimate only if it is a setup you trade, with its own stop from its own chart and the formula rerun. A skipped trade costs nothing.

Put commissions and slippage inside R

A triggered stop order becomes a market order and can fill a tick or several beyond your price in a fast market, and commissions and fees are charged on every contract. Leave them out and your real loss at the stop is always larger than 1R.

Two habits fix this. Include an estimate of round-trip costs and stop slippage in the per-contract risk, as in the examples above. Then record every closed trade in your journal as net R: the net dollar result, after costs, divided by the 1R you planned. Over time this shows whether your slippage estimate is honest.

Overnight positions and release days add gap risk: price can open beyond your stop, and the fill is wherever the market trades, not your stop price. 1R is a plan, not a cap on what you can lose.

Scaling 1R as the account changes

Recalculate 1R on a fixed schedule, such as the first trading day of each week or month, from the account balance at that time. Do not recalculate it mid-session.

Illustrative example: the $25,000 account falls to $22,000 after a bad month. At 0.5%, 1R becomes $110. The same 8-point MES trade from earlier is now $110 / $42.75 = 2.57, still 2 contracts. Before costs, a 12-point MES stop allowed 2 contracts at $125 ($125 / $60 = 2.08) but allows only 1 at $110 ($110 / $60 = 1.83). This is how percentage risk slows a drawdown without any willpower.

Recalculate after deposits or withdrawals too. Correlated positions share one budget: MES and MNQ opened together on the same idea are often one trade, so their combined risk should fit inside 1R. More on this on the risk topic page.

Common mistakes

• Moving the stop further away after entry. Widening an 8-point MES stop to 16 points on two contracts turns a $85.50 plan into roughly a $165 loss, well over 1R. The size was correct only for the original stop.
• Sizing up after losses (or raising 1R after wins). Doubling contracts to win back a loss makes the next loss twice as large, when judgement is weakest. 1R changes only at the scheduled recalculation.
• Rounding up. In the MES example, turning 2.92 into 3 contracts puts $128.25 at risk against a $125 1R; small on one trade, but across a run of losses the excess adds up.
• Mixing up tick values. Using the MES tick value for an MNQ trade overstates risk; the reverse understates it by a factor of 2.5.

Pre-trade sizing checklist

1. Today's 1R in dollars is written down, and it matches the scheduled recalculation.
2. The stop is placed at the level that invalidates the setup.
3. Stop distance in points is converted to ticks (points x 4 for MES and MNQ).
4. The correct tick value is used: $1.25 for MES, $0.50 for MNQ (confirm on cmegroup.com).
5. Round-trip costs and an honest slippage estimate are added per contract.
6. Contracts = 1R divided by all-in risk per contract, rounded down.
7. If the result is zero, the trade is skipped.
8. Any open position on a correlated contract is counted against the same 1R.
9. The stop order is entered with the position, and it will not be moved further away.

Scheduled releases widen ranges, so check the market news page before you size. Everything above is education, not a recommendation to trade any contract; futures carry a substantial risk of loss, and all examples here are illustrative.

Examples use round, illustrative numbers and are not actual trades or results. Education only — not investment, tax or legal advice.

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