Set your size once.
On Alertsify, Position sizing sizes every order from the chart for you, by $ Amount, % Account or # Contracts. Work out your number here, set it once, and each order uses it.
Free tool
Position size calculator.
Set your account size, how much you'll risk and where your stop goes. Get the most shares or option contracts you can take without losing more than that at the stop.
Rounds down, always. No sign-up, nothing sent anywhere: the math runs in your browser.
Result
Max shares
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- $ at risk
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- Risk, % of account
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- Position cost
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- Cost, % of account
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The loss at your stop assumes the order fills at the stop price. Gaps, fast markets and wide option spreads can fill worse, so the real loss can be bigger. Ignores commissions and fees. Not financial advice; options carry risk.
How it works
Size from the stop, not the hunch.
Decide what one losing trade may cost you, then let the distance to your stop set the size.
1. Risk budgetAccount size times your risk percent, or the dollar amount you entered.
2. Risk per unitEntry minus stop for a share. For an option, the premium drop times 100 shares per contract.
3. SizeBudget divided by risk per unit, rounded down to a whole share or contract so you never go over.
Example: a $25,000 account risking 1% has a $250 budget. A stock bought at $50 with a stop at $48 risks $2 a share, so the size is 125 shares, costing $6,250.
On the chart
- $ AmountSpend up to a set number of dollars on each order
- % AccountSpend a set share of your buying power
- # ContractsThe same count on every order
FAQ
Position sizing, explained.
How do I calculate position size?
Multiply your account size by the percent you are willing to risk to get a dollar budget. Divide that budget by the distance from your entry to your stop. Round down to a whole number of shares. For options, use the premium drop per share times 100 for each contract.
How much should I risk per trade?
Many traders choose a small fixed percent of the account per trade so that a run of losses does not wipe them out. The right number depends on you; this calculator only does the math for the number you pick.
Why does the calculator round down?
Rounding up would put more than your budget at risk. Rounding down to a whole share or contract keeps the loss at your stop at or under the amount you chose.
How does position sizing work for options?
An option contract covers 100 shares, so a premium drop of $0.80 from entry to stop risks $80 per contract. The calculator divides your budget by that amount. A stop premium of 0 means you are risking the whole premium.
Why does it say my stop is on the wrong side?
For a long trade or a bought option, the stop must be below the entry, because that is where you would be losing. For a short stock trade, the stop must be above the entry.
Can my loss be bigger than the calculator shows?
Yes. The math assumes you exit exactly at the stop. A gap or a fast market can fill your exit at a worse price, and option spreads can be wide. Not financial advice; options carry risk.
Size it here. Trade it from the chart.
Free account. No card needed.
This calculator is an educational tool, not advice. It cannot promise your loss stops at the stop price. Alertsify is a self-directed software tool and is not a registered investment adviser or broker-dealer. All trading involves risk.