Complete guide
Position Size Calculator: formula, example and decision guide
Calculate units that place a selected account amount at risk between entry and stop prices. The result updates instantly and keeps every assumption visible.
What the Position Size Calculator measures
Calculate units that place a selected account amount at risk between entry and stop prices.
Use the result to compare scenarios built from the same definitions and time period.
Formula and variables
The calculator applies units = (account × risk percentage − fees) ÷ |entry − stop|. Each variable is entered in a labeled field and remains visible beside the answer.
units = (account × risk percentage − fees) ÷ |entry − stop|Worked example
A $25,000 account risking 1% with a $5 stop distance and $10 fees permits 48 units.
Change one input at a time to see which assumption has the greatest effect on the result.
How to interpret the result
Read the main result together with the detailed rows; the headline number alone does not describe every cost, unit or assumption.
Save comparable scenarios with the copy, link, CSV or PDF controls.
Assumptions and limitations
Stops can gap or fail to execute at the selected price; liquidity, slippage, leverage and fees can increase loss.
Real contracts, measurements, platform rules and professional standards can add inputs that this general-purpose model does not infer.
Accuracy checklist
Confirm units, time periods, fees and source figures before relying on the output.
Round the displayed answer only after the calculation; intermediate values retain full precision.
Calculation audit
| Item | What to review |
|---|---|
| Inputs | Account value, Risk per trade (%), Entry price, Stop price, Estimated round-trip fees |
| Equation | units = (account × risk percentage − fees) ÷ |entry − stop| |
| Example | A $25,000 account risking 1% with a $5 stop distance and $10 fees permits 48 units. |
| Limit | Stops can gap or fail to execute at the selected price; liquidity, slippage, leverage and fees can increase loss. |
Frequently asked questions
What does this Position Size Calculator calculate?
Calculate units that place a selected account amount at risk between entry and stop prices.
Which formula does it use?
units = (account × risk percentage − fees) ÷ |entry − stop|
Does it calculate while I type?
Yes. Valid changes update the result automatically without reloading the page.
Which inputs should I verify?
Verify every unit, period, rate and fee against the source you are modeling.
Is the result exact?
Stops can gap or fail to execute at the selected price; liquidity, slippage, leverage and fees can increase loss.
Can I save or share the result?
Yes. Copy, native sharing, WhatsApp, PDF/Print, CSV, comparison and parameterized links are available.
What to keep in mind
Stops can gap or fail to execute at the selected price; liquidity, slippage, leverage and fees can increase loss.
Results display up to 8 decimal places; exported numbers preserve calculation precision. This is a calculation summary, not an official certificate.