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Delta-adjusted position size calculator
The plain position sizer assumes your loss equals the stop distance. On an option it does not: a four-point move against a 0.50-delta contract is about two points of premium. Sizing off the underlying alone overstates the loss and leaves you smaller than you intended.
These calculators do arithmetic on numbers you enter. They do not produce recommendations, do not connect to any market feed, and do not know what any instrument is worth — that is never advice, and it is not a substitute for your own judgement or a licensed professional's.
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to use the delta-adjusted position size calculator — and the other 6: Position Size, Risk : Reward, Margin & Leverage, Drawdown, Options Payoff, Monte Carlo
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How this is calculated
No hidden model and nothing fitted to data. Every figure on this page comes out of these lines, applied to the numbers you typed.
risk budget = account size x risk %
delta per lot = |delta| x units per contract
risk per contract = stop distance x delta per lot
contracts = floor( risk budget / risk per contract )
equivalent units = contracts x delta per lot
premium outlay = contracts x premium x units per contractThe other three
Position Size
How many units does my risk budget actually buy?
Risk : Reward
What win rate does this payoff need to break even?
Margin & Leverage
How far can this move against me before maintenance?
Drawdown
What does this decline demand back before it is undone?
Options Payoff
Where does this position break even, and what is the worst case?
Monte Carlo
How different can the same edge look across a thousand runs?
Frequently asked questions
- Why is delta-adjusted sizing different from ordinary position sizing?
- Because the stop and the loss are measured in different things. Your stop is a level in the underlying, but what you actually lose is premium, and an option's premium moves by roughly its delta for each point the underlying moves. Sizing as though a four-point stop costs four points per unit overstates the loss on any option with a delta below 1, and leaves the position smaller than the stated risk allows.
- How accurate is the delta estimate?
- It is a first-order approximation and it is least accurate exactly when it matters most. Delta is not constant: it changes as the underlying moves, which is gamma, and it decays as expiry approaches, which interacts with theta. Over a small move it is close; over the large, fast move that would actually hit your stop, the real premium change can differ substantially.
- Should I use the premium or the stop as my risk?
- They are two different numbers and the calculator shows both, because whichever is larger is what you can actually lose. A long option cannot lose more than the premium paid, however far the underlying runs - so if the premium outlay is smaller than the stop-based risk, the premium is your true maximum. If the option expires worthless, the whole premium is gone regardless of where the stop sat.
- What is delta-equivalent exposure?
- How many units of the underlying the position currently behaves like - contracts multiplied by the contract multiplier and by delta. It is usually the figure that surprises people: a few cheap contracts can behave like a stock position worth many times the premium paid for them, which is what leverage means in this context.
- Does a put's negative delta need a minus sign?
- No, the magnitude is what matters and the sign is ignored. A put with a delta of -0.40 moves 0.40 of a point of premium per point of underlying, exactly as a 0.40-delta call does; the direction is already expressed by which instrument you chose and where your stop sits.
- Are my figures sent anywhere?
- No. The arithmetic runs in your browser as JavaScript on this page. Your account size, risk percentage and stop are never transmitted, never stored and never logged, and closing the tab discards them. A free account unlocks the calculator; it does not send anyone your numbers.
⚠ Important disclaimer
These calculators are provided strictly for educational and informational purposes. They perform arithmetic on figures you enter. Nothing on these pages is financial, investment, trading, legal or tax advice, nor a recommendation to buy, sell or hold any security, derivative, commodity or cryptocurrency.
The creator is not a registered investment adviser, research analyst or broker with the SEC, FINRA, CFTC, NFA, any U.S. state securities regulator, or SEBI (as an Investment Adviser or Research Analyst). Trading involves substantial risk of loss — you can lose some or all of your capital, and with leveraged instruments you can lose more than you deposit.
Contract specifications, lot sizes and margin rates shown here are seeded from published standards, are editable, and may be out of date or wrong for your broker. Exchanges revise lot sizes and margin requirements, and brokers routinely impose more than the regulatory minimum. Verify every figure against your own broker before acting on it. These tools carry no warranty of any kind and may contain errors.
You are solely responsible for your own decisions. Read the full legal disclaimer →