Stock & Contract Profit Calculator: How to Measure True ROI, Fees & Slippage

'I bought at $50 and sold at $55, that's 10%.' Almost. Between entry and exit, three silent costs take their cut: commissions, the bid/ask spread and slippage. For a single trade the difference looks small; across a year of trading it decides whether the strategy works at all.

This guide shows the net profit formula, where the hidden costs hide, and how ROI changes completely depending on whether you measure it on the cash invested, the notional controlled or the margin posted. The stock profit calculator and futures calculator run every example below for free.

The net profit formula

The costs that quietly eat your return

• Commissions, the visible one. Flat per trade, per share or per contract; always count both sides (entry and exit).
• Bid/ask spread, you buy at the ask and sell at the bid. On a $0.05 spread, 100 shares lose $5 before the trade starts. Wide spreads on illiquid names are a silent tax.
• Slippage, the gap between the price you clicked and the price you got. Market orders in fast or thin markets slip most; limit orders trade certainty of price for certainty of fill.
• Regulatory & exchange fees, small per-trade charges (SEC/TAF on US stock sales, exchange and NFA fees on futures). Cents each, real money in aggregate.
• Financing & borrow costs, holding leveraged CFD/short positions overnight incurs financing; hard-to-borrow shorts can cost several % a year. Crypto perpetuals pay or receive funding every few hours.

Slippage: the invisible fee you can estimate

Slippage isn't on any broker statement, so most traders never measure it. Estimate it with a simple rule: slippage ≈ half the spread + market impact. Liquid large caps and ES futures in regular hours: often 0–1 ticks. News events, illiquid small caps or thin crypto pairs: many ticks, sometimes more than the planned profit.

Stocks divide profit by the cash you paid. Leveraged products let you pick a denominator, and the choice changes the story. Take 1 ES futures contract at 6,000 ($300,000 notional, ~$1,000 day margin) that gains 10 points:

All three are true; only one is honest for planning. Measuring returns on account equity keeps risk honest, the margin version flatters wins and hides that the same trade could have lost 50% just as easily. Our futures calculator reports net P&L after commissions; divide by your account equity for the return that matters.

Comparing trades fairly: R multiples and expectancy

A $500 win means different things on a $5,000 and a $500,000 account. Two fixes:

• Return on equity (%), net profit ÷ account value. Comparable across time as the account grows or shrinks.
• R multiple, net profit ÷ the risk you planned (entry−stop distance × size). A +2R trade is a +2R trade on any account. The risk/reward calculator shows the R of a plan before entry.

Combine them and you get expectancy, win rate × average win − loss rate × average loss, the single number that says whether a strategy earns at all. Computing it needs every trade's net result, which is why measuring by hand stops working around trade #50 and a synced journal takes over.

Net profit, explained like you're five

Forget the formulas for a minute, all of this fits inside a Saturday card fair.

The trading-card stand

Imagine you buy 100 rare cards for $5 each and sell them for $6 at the fair. Feels like you made $100, right? Not so fast, the fair charges for everything. Three magic terms:

• Gross profit: the $100 you think you made, the price difference before anyone takes their cut.
• Costs: the $10 stand fee, the $4 for card sleeves, and the $2 the change kid kept because your $6 cards actually sold at $5.98.
• Net profit: the $84 that actually lands in your pocket. That's the only number that's real.

Why this is dangerous

Now imagine doing 50 fairs a year and bragging about '$100 per fair'. Two ways that goes wrong:

• The mistake many make: they count the $100 gross in their head and spend it. The fees were small every time, $16 a fair, but that's $800 a year, a whole vacation traded away to costs nobody tracked.
• The reality: the stand that 'wins' $100 can actually lose money if the fees pass $16. A fair with $20 of costs is a losing stand wearing a winning costume.

From one trade to a track record

A calculator is perfect before and after a single trade. But your edge lives in the aggregate: net P&L after all costs, expectancy per setup, and the leaks you can't see one trade at a time, the hour you always lose, the day you oversize. NovaTrade syncs your MT4/MT5, cTrader and exchange trades automatically and turns them into exactly those numbers, start free and let the journal do the math.