Spot Position Size Calculator

Free tool · Spot trading

Spot position size calculator

Enter your balance, your risk and your stop. Get exactly how much to buy, with trading fees included and a cap so you never size beyond your balance.

Your trade

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Spot trading is long only: you buy first and sell higher. Shorting needs margin or futures, which this calculator does not cover. For education and risk planning only. Not financial advice or a buy or sell signal.

How the spot calculation works

Position size comes from how much you are willing to lose, not how much you want to own. Fees on both the buy and the sell are included, because they make a stop-out cost slightly more than the price distance alone.

Loss per unit = Entry x (1 + fee) – Stop x (1 – fee)
Position size = Risk amount / Loss per unit
Capped at: Balance / (Entry x (1 + fee))

Why a cap?

In spot trading you cannot buy more than your balance. A tight stop can imply a position larger than your account. The calculator then caps the size and shows your real, smaller risk.

Why fees matter

A 0.1% fee on each side is 0.2% round trip, which adds to every loss and shrinks every gain. It matters most on tight stops and small targets.

What is R?

1R is the amount you risk on the trade. A target at 2R pays twice what you risk. The table of R targets shows the price needed for each.

Want the theory behind it? Read our risk guides on position sizing, stop placement and losing streaks.