Position sizing calculator

The most important risk tool in trading. Enter your account size, the risk you'll accept per trade, your entry and your stop — get the exact position size that caps your loss. Works for crypto, stocks and forex. Free, instant, no signup.

Position size (units)
Position value
$ at risk

Implied leverage on this account:

The formula

position sizingunits = (account × risk%) ÷ |entry − stop|

# Example: $10,000 account, 1% risk, entry 42000, stop 40000
risk_amount = 10000 × 0.01 = $100
per_unit    = |42000 − 40000| = 2000
units       = 100 ÷ 2000 = 0.05 units  # worth $2,100

If the stop is hit, you lose exactly $100 — your chosen 1%. This is the same function our build guide wires into a real bot, so your automated system never bets the farm.

Why this matters more than your strategy

You can have a mediocre strategy and survive for years with disciplined 1% sizing. You can have a brilliant strategy and blow up in a week without it. Position sizing is the difference between a hobby and a wipeout.

How to use it with your bot

  1. Decide your fixed risk per trade (1% is a sane default).
  2. For each signal, feed the entry and stop into this formula.
  3. Trade exactly the resulting size — never round up "because you feel good."
  4. Pair with the win-rate profit calculator to project long-run results.
Not financial advice. This content is educational. Automated and algorithmic trading carries a real risk of financial loss. Never trade money you cannot afford to lose. Review the SEC investor.gov and CFTC resources before trading.

Frequently asked questions

How do you calculate position size?

Position size = (account balance × risk percent) ÷ (entry price − stop price). This gives the number of units to buy so that if the stop is hit, you lose exactly your chosen risk percentage of the account.

What risk percent should I use per trade?

Most disciplined traders risk 0.5% to 2% of their account per trade. Risking 1% means it would take many consecutive losses to do serious damage, which keeps you in the game long enough for your edge to play out.

Does position sizing work for crypto and stocks?

Yes. The risk-based formula is asset-agnostic — it works for Bitcoin, stocks, forex or futures. Only the price scale changes; the math is identical.

What is leverage in position sizing?

Leverage is position value divided by account equity. A 3x leverage means your position is three times your account size. Higher leverage magnifies both gains and losses, so beginners should keep it at 1x.

MB

Mustafa Bilgic

Algorithmic trading practitioner · Founder, AITradingBot.us

Mustafa builds and backtests automated trading systems and writes about them without the hype. Every tool on this site is free and runs entirely in your browser.