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Risk a fixed fraction
Pros risk a small, constant slice of equity per trade — typically 0.5–2%. The calculator turns that rule into an exact number of units so a single bad trade can never sink you.
Size every bot trade with precise risk & compounding math
Before your automated strategy fires a single order, work out the exact position size, dollar risk and reward-to-risk ratio — then project where disciplined compounding actually takes your account. Two correct calculators, zero fluff.
Risk & Position Size
Size each trade by the dollars you can afford to lose
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Position Size
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Notional $
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Risk $
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Reward : Risk
Compounding Projector
Where a repeatable edge takes your equity
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Final Equity
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Net Profit
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Total Growth
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Monthly Rate
Educational tool — not financial advice. Position sizing uses the standard fixed-fractional formula; the projector compounds a constant per-trade return and assumes the edge never fails — a best-case illustration, not a prediction. Real automated trading carries a genuine risk of loss from slippage, fees, gaps and drawdowns. Review SEC investor.gov and CFTC guidance before trading.
Why these two numbers decide everything
Strategy choice gets the headlines, but position size and compounding are what actually keep an automated account alive — and growing.
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Demand a real edge
The reward-to-risk ratio tells you the win rate you must clear to break even. A 2:1 trade only needs to be right 34% of the time — sizing and R:R are joined at the hip.
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Let math do the work
A modest, repeatable edge compounds into serious numbers — but only if drawdowns stay small. The projector shows the curve so you can feel the trade-off.
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Units & dollars
You get both the share/coin/contract count and the dollar notional, plus whether that notional needs leverage above your cash balance.
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Fully private
Everything runs in your browser. No account, no upload, no tracking of your numbers. Refresh and it's gone.
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Wire it into a bot
Use these formulas directly in your bot's order-sizing function. Our build guide shows the Python.
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In-browser
More free trading-bot calculators
Single-purpose tools for the rest of the risk-and-sizing toolkit. Each runs in your browser, shows its formula, and stores nothing.
Bot building & operations guides
Practical, original guides on planning, building and running automated strategies — written without the hype.
Risk, sizing & validation
The methodology that separates a bot that survives a bad month from one that blows up.
Frequently asked questions
How is position size calculated?
Position size equals your dollar risk divided by the per-unit risk. Dollar risk is account × risk%; per-unit risk is the absolute distance between entry and stop. So size = (account × risk%) ÷ |entry − stop|. The notional value is that size times the entry price — if it exceeds your cash, you'd need margin or leverage.
What reward-to-risk ratio should I aim for?
There's no single answer — it trades off against win rate. A 1:1 trade needs to win more than 50% of the time to profit; a 2:1 trade only needs ~34%; a 3:1 needs ~25%. The calculator shows the break-even win rate for whatever target you enter. Read more in risk management.
Why does my compounding projection look unrealistic?
Because it assumes a constant positive return on every trade with no losing streaks, fees or slippage. That never happens. Use it to understand the shape of compounding and to sanity-check a target, not as a forecast. Validate any edge with forward testing first.
Is anything saved or sent to a server?
No. Both calculators are pure client-side JavaScript. Your numbers never leave the page, and nothing is stored. Close the tab and it's gone.