Traders Calculator
Traders calculator works out Profit or loss and Cost basis from Instrument, Quantity bought and Quantity (alternative name). The default figures on this page give position size of 40.000000; change any entry and the result, the working and the sources update together.
Your figures
Updates as you typeHow this is worked out
3 steps
- Risk budget = 20000 x 1% = 200
- Risk per unit = |50 - 45| x 1 = 5
- Position size = 200 / 5 = 40 shares
Its 5 worked examples are re-run on every release, last on 15 September 2026. What changed
Sources and references
2 sources
Keep this result
Save it, change one figure, then compare the two
The calculation stays free. Save this scenario, adjust one assumption, save that too, and put them side by side to see exactly what the change costs you. A free account keeps 5 scenarios and 2 comparisons; Personal makes both unlimited and adds exports and private links. Nothing is saved unless you press Save.
What the traders calculator calculates
Works out the profit or loss on a share, crypto or futures trade from the buy price, sell price, quantity and both sides of commission, and reports the cost basis, gross proceeds, return percentage and the break-even sell price; it can also size a position from the amount of account equity you are willing to risk.
How to use this traders calculator
Enter Instrument, Quantity bought, Quantity (alternative name) and Buy price per unit. Profit or loss updates as you type. Change one figure at a time to see what drives the result.
How the result is worked out
Open “How this is worked out” beside the result for the step-by-step calculation behind Profit or loss, Cost basis and Gross proceeds.
The method follows U.S. Securities and Exchange Commission - Cost Basis for Securities Transactions and Fixed-fractional position sizing: shares = risk budget / risk per share.
What you can compare
Change one input at a time to see how it affects Profit or loss, Cost basis and Gross proceeds. The inputs you can vary are Instrument, Quantity bought, Quantity (alternative name), Buy price per unit, Sell price per unit and Buy-side commission and fees.
Results are general information, not financial, tax, legal, medical or engineering advice. Check any decision that matters with a qualified professional.
See something wrong? Report a problem with this calculator
Frequently asked questions
What information do I need for the traders calculator?
You need Instrument, Quantity bought, Quantity (alternative name), Buy price per unit, Sell price per unit, Buy-side commission and fees, Sell-side commission and fees and Contract multiplier. The page opens with default figures that give position size of 40.000000, so you can see the scale before entering your own.
What does this traders calculator show?
It shows Profit or loss, Cost basis, Gross proceeds, Total commission and fees, Net proceeds after sell-side fees, Return on capital invested, Break-even sell price and Position size, with the working and any warnings for your entries.
Can I check how the traders calculator result was calculated?
Yes. The “How this is worked out” section shows the calculation steps, and the sources section identifies the references used for the method.