CoinSoso

Type to search across the site.

    Press Esc to close

    Tool

    Position Size Calculator

    Decide how large a position your stop-loss distance allows, given the amount of your account you are willing to lose on a single trade.

    Your setup

    $
    %
    $
    $
    Direction

    Long means the stop sits below entry. Short means it sits above.

    The formula

    The position size follows from the loss you are prepared to take and the distance to the stop.

    riskAmount     = balance × (riskPercent ÷ 100)
stopDistance   = |entryPrice − stopPrice|
positionSize   = riskAmount ÷ stopDistance
positionValue  = positionSize × entryPrice
leverageImplied = positionValue ÷ balance

    Assumptions

    • The full amount at risk is lost only if the stop fills exactly at the stop price, with no slippage.
    • Fees, funding payments and spread are excluded, so the real loss on a stopped-out trade is larger.
    • The balance is treated as the whole account. If you keep only part of your capital on the venue, enter that part.
    • Implied leverage is a derived figure. It is not a suggestion to configure your account at that leverage.

    What each field expects

    • Account balance — the capital this trade is allowed to draw on. If you keep only part of your funds on the venue, enter that part rather than your total holdings, because the leverage figure is measured against it.
    • Risk per trade — the percentage of that balance you accept losing if the stop fills. This is a decision, not a calculation: the tool does not choose one for you.
    • Entry price and stop-loss price — the prices you expect to enter and exit at. The distance between them is what converts a risk amount into a quantity.
    • Direction — long means the stop sits below entry, short means it sits above. A stop on the wrong side is rejected rather than producing a negative size.

    Worked example

    A 10,000 balance, 1% risked, entering long at 65,000 with the stop at 63,000:

    riskAmount     = 10000 × (1 ÷ 100)      = 100
stopDistance   = |65000 − 63000|        = 2000
positionSize   = 100 ÷ 2000             = 0.05
positionValue  = 0.05 × 65000           = 3250
leverageImplied = 3250 ÷ 10000          = 0.33×

    So 0.05 of the asset, worth 3,250, puts 100 at risk if the stop fills at 63,000. Moving the stop closer changes the size and not the risk: at a stop of 64,000 the distance halves to 1,000, the size doubles to 0.1, the position value doubles to 6,500 and the implied leverage rises to 0.65×. A tighter stop buys a bigger position for the same loss, which is exactly why it also makes the stop easier to hit.

    Input handling

    A balance of zero or less, a risk percentage outside 0–100%, and non-numeric text are all rejected with a specific message. A stop-loss equal to the entry price is rejected because the risk per unit would be zero and no finite position size exists. If the stop is on the wrong side of the entry for the direction you chose, the tool says so rather than returning a meaningless number.

    Related reading

    This calculator sizes the position but not the cost of running it. The trading fee calculator works out the round-trip fee on the position value shown here, and how to read a crypto exchange fee schedule is where those rates come from.

    A stop is an instruction, not a guarantee

    The amount at risk assumes the stop fills at the price you entered. If the market moves through it quickly the fill can be worse, and fees, funding and slippage add to the real loss — so the figure here is a floor on what a stopped-out trade costs, not a ceiling. Implied leverage is a consequence of your inputs, not a recommendation to set your venue leverage to that number: where a position is margined, liquidation can occur before the stop is reached.

    Frequently asked questions

    Why does the calculator reject my stop-loss price?

    For a long position the stop-loss must sit below the entry price, and for a short position it must sit above it. If the stop is on the wrong side, the position would be closed immediately and the risk per unit would have no meaning, so the tool explains the problem instead of returning a negative or infinite size.

    What is the difference between position size and position value?

    Position size is the quantity of the asset, such as 0.25 BTC. Position value, also called notional, is that quantity multiplied by the entry price. Your stop-loss distance determines the size; the entry price determines the value.

    Does the leverage figure mean I should use that leverage?

    No. It is the leverage implied by the position value divided by the balance you entered. Some venues require you to set leverage explicitly, and liquidation happens before the stop if leverage is set too high or the stop is wide relative to the balance. Treat the figure as a consequence of your inputs, not as a recommendation.

    Does this account for fees and funding?

    No. The risk figure covers the distance from entry to stop only. Fees, funding on perpetuals, and slippage on the exit add to the real loss, so many traders size slightly smaller than the calculated figure.