Quick Answer
Gross profit equals price change times the contract multiplier times contracts (long: exit minus entry; short: entry minus exit). Net profit subtracts the round-turn commission, charged once per contract. Return on margin equity divides net profit by the initial margin posted, not the full contract value.
The whole calculation-heavy unit on one sheet: turn a price move into gross profit, net out the commission, and measure the return against the margin actually posted.
How Do You Find Gross Profit on a Straight Long or Short?
- Formula: Gross P/L = (exit minus entry) times contract multiplier times number of contracts. A long gains when price rises (exit minus entry); a short gains when price falls, so the subtraction flips to entry minus exit.
- Contract multiplier is a fixed dollar value per unit of price movement: corn is 1 cent per bushel equals $50 per contract; E-mini S&P 500 is 1.00 index point equals $50 per contract. Scale by the number of contracts last.
- Worked: long 420 to 435, 1 contract, is (435 minus 420) times $50, or $750. Short 460 to 448, 3 contracts, is (460 minus 448) times $50 times 3, or $1,800.
How Does a Spread's Profit or Loss Get Calculated?
- Only the change in the spread, the difference between the two legs, turns into profit or loss; a single leg can move a lot while the spread barely changes. Multiply the change in the spread by the multiplier and the number of spreads.
- Worked: July minus 20 under December narrows to minus 8, a 12-cent favorable change; 12 times $50 times 1 spread is $600.
How Do Commissions Turn Gross Profit into Net Profit?
- A round-turn commission covers the complete trade cycle, entry and exit, in one charge. Multiply the rate by the number of contracts and subtract once; charging it on the buy and again on the sell double-counts the cost.
- Net profit = gross profit minus total round-turn commissions, and it always moves the result in the losing direction: it shrinks a gain and enlarges a loss.
- Worked: $750 gross minus a $50 commission is $700 net; a $200 gross loss minus the same $50 commission is a $250 net loss.
How Do You Find the Return on Margin Equity?
- Formula: Return on margin equity = net profit divided by the initial margin deposited, not the full contract value. Margin is a performance bond, not a loan, so no interest is charged on it, unlike securities margin.
- Worked: $700 net divided by $2,000 margin is 35%, versus only about 3.3% against the $21,000 notional value. On 3 contracts, $1,650 net divided by $6,000 margin is 27.5%.
Which Numbers Matter Most?
| Item | Value |
|---|---|
| Corn contract multiplier | 1 cent/bushel = $50/contract (5,000 bushels) |
| E-mini S&P 500 multiplier | 1.00 index point = $50/contract |
| Gross P/L formula | (exit minus entry) x multiplier x contracts; flip for a short |
| Net profit formula | Gross profit minus total round-turn commissions |
| Return on margin equity formula | Net profit divided by initial margin deposited |
| Worked long result | $750 gross, $700 net, 35% return on $2,000 margin |
| Worked short result (3 contracts) | $1,800 gross, $1,650 net, 27.5% return on $6,000 margin |
Which Gotchas Trip Students Up?
- A short profits when price FALLS, not rises. Compute entry minus exit; the opposite instinct is backwards.
- A price change is not dollars until multiplied by the contract multiplier, the most common gross-profit error.
- A round-turn commission is subtracted once for the whole trade, not once per leg, and it makes a loss bigger, never smaller.
- Return on margin equity divides by the margin deposited, not the full contract value, or the answer badly understates the return and misses the point of leverage.
- Futures margin carries no interest deduction, unlike a margined stock position, because it is the trader's own collateral.
One-Breath Recap
Gross profit on a speculative futures trade is the price change times the contract multiplier times the number of contracts, with a long using exit minus entry, a short flipping to entry minus exit, and a spread using only the change in the spread; net profit then subtracts the round-turn commission, charged once per contract for the whole trade, which shrinks a gain and enlarges a loss; and return on margin equity divides that net profit by the initial margin actually deposited, not the full contract value, which is why a modest move posts a large percentage, since futures margin is a performance bond carrying no interest.
Need more than the recap? Read the full Profit and Loss Calculations unit.