Position Size Calculator

Account, risk budget and stop distance → position notional and account exposure

What is the Position Size Calculator?

The Position Size Calculator works risk-first: given account size, per-trade risk (1–2% recommended) and stop distance, it derives the maximum position you should open.

How do I use the Position Size Calculator?

The correct order: set the stop first (from technical structure), then let the tool size the position — never the reverse. At ≤2% risk per trade, even ten consecutive stops cost only ~18%, keeping the account alive.

What should I watch out for?

Slippage and wicks in fast markets can push real losses past the planned risk, and leverage scales position size, not win rate. Of every tool on this site, this is the one to use before every single trade.

How the Position Size Calculator works

Works backward from risk: given your account size, the share you are willing to lose on one trade, and your entry and stop prices, it calculates position notional and coin quantity. Built for traders who set the stop before choosing size.

What you enter

  • Account size (USD), default 10,000
  • Risk per trade (%), 0 to 100, default 2
  • Entry price (USD), default 50,000
  • Stop price (USD), default 48,000; below entry implies a long, above entry a short

What it shows

  • Position notional (USD) and coin units, labeled Long or Short
  • Planned stop loss in USD, before costs
  • Stop distance (%)
  • Notional / account (exposure multiple)
  • Capital required at 1×

How to use it

  1. Enter your account size in USD.
  2. Set risk per trade (%), for example 1 or 2.
  3. Enter your planned entry price.
  4. Enter the stop price taken from your chart structure.
  5. Read the position notional and units; the inputs are stored in the URL so you can share the result.

Formula

Risk USD = account × risk % / 100; units = risk USD / |entry − stop|; notional = units × entry; stop distance % = |entry − stop| / entry × 100; exposure = notional / account.

Worked example

Account 10,000 USD, 2% risk, entry 50,000 USD, stop 48,000 USD. Risk = 10,000 × 0.02 = 200 USD. Units = 200 / 2,000 = 0.1 BTC. Notional = 0.1 × 50,000 = 5,000 USD. Stop distance = 2,000 / 50,000 = 4%. Exposure = 5,000 / 10,000 = 0.5×.

How to read the result

  • Notional does not depend on leverage; leverage only changes the margin you post.
  • A tighter stop gives a larger notional for the same dollar risk.
  • Exposure above 1× means you need leverage to open the calculated size.

Limits and cautions

  • Fees, slippage and funding are excluded; a stop can fill worse than planned.
  • Gaps and wicks can make the actual loss exceed the planned risk.
  • If you use leverage, make sure the liquidation price sits beyond your stop.

Common questions

How do you calculate position size in crypto?

Divide the dollar amount you will risk (account × risk %) by the distance from entry to stop. That gives the quantity; multiply it by the entry price for the notional.

What risk per trade should I use?

Many traders use 1% to 2% of the account per trade. At 2%, ten full losses in a row leave about 0.98^10 ≈ 81.7% of the account.

Does leverage change position size?

No. The risk-based notional is the same; leverage only reduces the margin needed to hold it and moves the liquidation price closer.

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