Position Sizer
Turn your risk limit and your stop into a share count, contract count or FX lot size.
Comes with: Free for everyone. The attach-to-plan and duplicate-exposure checks come with any ITPM course (Core Workbench).
you entercalculated
Using the Position Sizer
Instrument
Risk choice
Trade levels
Position sizing is free for everyone. The rest of the Workbench comes with a course enrolment made through this site. See what else is in the Workbench.
Turn your risk limit into a position size: the number of shares, contracts or lots whose planned loss at your stop stays within the amount you chose.
Steps
- 1
Set your risk FIRST: either a % of your book size, or a direct £/$ amount. You choose the path. There is no pre-filled default.
- 2
Pick the mode that matches what you are sizing: Stocks, Options, or FX.
- 3
Stocks: enter your entry and stop. The sizer floors to a whole number of shares, keeping the planned loss at your stop within the amount you set.
- 4
Options: enter the max loss of ONE contract of your defined-risk structure, already the whole-contract £/$ figure. The sizer floors to a whole number of contracts.
- 5
FX: enter the pair, lot type and stop distance in pips. The sizer floors your lot size down to 2 decimal places, keeping the planned loss at your stop within the amount you set.
- 6
Read the result against your risk limit, not the other way round. If the size looks too big or too small for the trade, change your stop or your risk setting. Do not chase a round number.
Definitions for every number
- riskAmount
Definition: The £/$ amount you decided to risk on this trade, whichever way you set it: a % of your book, or typed directly.
Use: This is the number every size in this tool is built to stay at or under.
Limit: Not a target to hit, and not a recommendation of how much you should risk. That limit is yours to set.
- riskPct
Definition: The risk amount expressed as a percentage of the book size you entered.
Use: Compare it to the per-trade limit you already hold yourself to.
Limit: This is not a suggested figure. The field ships blank on purpose; there is no default percentage anywhere in this tool.
- entry
Definition: The price you intend to enter at.
Use: Used with your stop to work out the risk per share.
Limit: Not a live quote, and not a prediction. It is the price you plan to use.
- stop
Definition: The price at which this idea is wrong and you would exit for a loss.
Use: The distance between entry and stop is your risk per share; a tighter stop buys you a bigger position for the same £/$ risk.
Limit: Not a suggested level. It is the number you have already decided on.
- shares
Definition: The number of shares your risk amount buys you at this entry/stop, floored down to a whole share.
Use: Multiply by your entry price to see the capital this deploys.
Limit: It is not advice to take this position size, or to take the trade at all.
- positionValue
Definition: The total capital this position ties up: shares × entry price.
Use: Compare it to your book size. A small risk can still deploy a large chunk of capital when the stop is tight.
Limit: This is not the amount at risk; that is riskAtRoundedSize, which is usually much smaller.
- pctDeployed
Definition: Position value as a percentage of the book size you entered.
Use: A useful sanity check alongside % risked: capital deployed and capital at risk are two different limits.
Limit: Leave book size blank and this figure is not shown at all.
- maxLossPerContract
Definition: The worst-case £/$ loss on ONE contract of the defined-risk options structure you are sizing, already scaled for the standard 100-share contract multiplier.
Use: Take it straight from your structure’s max-loss line (e.g. the net debit paid on a debit spread, ×100).
Limit: This is not a per-share figure. Do not enter the max loss before multiplying by 100, or the size will be 100x too big.
- contracts
Definition: The number of contracts your risk amount buys at this max loss per contract, floored down to a whole contract.
Use: Multiply by the max loss per contract to see your actual risk at this size.
Limit: No advice here on which structure to use. That judgement is the course’s Options Structure Lab territory.
- pair
Definition: The currency pair you plan to trade, e.g. EUR/USD.
Use: Used to detect the quote currency, which sets the pip size.
Limit: The pair is not validated against a live symbol list. Typos will silently mis-detect JPY pairs, so check the pip size shown looks right.
- stopPips
Definition: Your stop distance in pips.
Use: Combined with pip value per lot to work out how many lots fit your risk amount.
Limit: Not a suggested distance. It is the stop you have already set.
- pipSize
Definition: The price movement one pip represents for this pair: 0.0001 normally, 0.01 when the quote currency is JPY.
Use: Detected automatically from the pair you typed. Check it against your broker if the pair is unusual.
Limit: This one is not editable. It is derived, not a setting.
- pipValue
Definition: How much one pip of movement is worth, in your account currency, for one whole lot of the size you chose.
Use: pipValue = lot units × pip size × your quote-to-account conversion rate.
Limit: The conversion rate is whatever you entered (default 1, labelled indicative). Enter your broker’s actual rate for an accurate figure. This is not a live FX quote.
- lots
Definition: The lot size your risk amount buys at this stop distance, rounded DOWN to 2 decimal places.
Use: Rounding down keeps the planned loss at your stop within your risk amount rather than a fraction above it.
Limit: Rounding here does not follow your broker’s minimum lot step. Check they allow the size shown.
- riskAtRoundedSize
Definition: The planned loss at your stop once your size is rounded down to a whole share, contract, or 2dp lot. It sits at or below the risk amount you set.
Use: The gap between this and your risk amount is the small "left on the table" from rounding down, on purpose, keeping the planned loss at your stop within the amount you chose.
Limit: Not your risk amount restated. If the two numbers differ, rounding is why.