Position Size Calculator

Work out exactly how many shares to buy based on your account size, risk tolerance, and stop-loss. The single most important calculation most traders skip.

Your trade

Currency

Account size ($)

Risk per trade (%)

Most professionals risk 1–2% of their account on any single trade.

Entry price ($)

Stop-loss price ($)

Result

Shares to buy

long position

Amount risked: $100.00
Risk per share: $2.00
Position value: $2,500.00
% of account: 25%
Loss if stopped out: -$100.00

Free share worth up to £100 when you sign up

Ready to put this into practice?

Trading 212 — Commission-free stocks & ETFs with fractional shares. Open an account in minutes and start applying what you learned here.

Zero-commission stock & ETF investing
Fractional shares from $1
Built-in Pies for automated portfolio rebalancing

Get started with Trading 212

Referral link · capital at risk

Related guides

Risk6 min read

How to Calculate Position Size (the 1% Rule Explained)

The formula pros use to size positions so one bad trade doesn't wreck your account.

Read guide