How do you calculate position size for swing trading?

Divide the dollar amount you are willing to risk by your stop-loss size per share: shares = account risk ($) ÷ (entry price − stop price). For example, risking 0.5% of a $10,000 account ($50) on a trade with a $50 entry and $48 stop ($2 stop size) sizes the position at 25 shares.

What percentage of my account should I risk per trade?

Many swing traders risk between 0.25% and 1% of their account per trade. Risk Calc always shows all three tiers — 0.25%, 0.5%, and 1% — side by side so you can choose position size based on your conviction and experience.

Why set a stop loss at the low of day?

The low of day is a common technical stop for momentum and breakout entries: if price falls back below it, the setup is usually invalidated. Risk Calc can lock your stop to the live low of day, updating your position size in real time as the low moves.

The core calculator is free with no sign-up: live prices, the 1-minute candle chart, the low-of-day stop lock, all three risk tiers on one account, and a ledger for up to three open positions. Risk Calc Pro ($15/month or $149/year) adds unlimited accounts, a 50-position ledger, custom risk presets, a closed-trade journal with R-multiples, portfolio heat, watchlist import, Google sign-in sync across devices, and CSV export.

Risk Calc — Position Size Calculator

Prices

Entry price

Stop price

Lock to low of day

Accounts

Custom risk %

Focus list

Position ledger

Portfolio heat

Trade journal

Free vs Pro

Free

Live price, 1-min candles, low-of-day stop lock
0.25% / 0.5% / 1% risk tiers on one account
Ledger for 3 open positions + tab-title pin
No sign-in required — data stays in your browser

Pro

$15/mo or $149/yr (~2 months free)

Unlimited accounts, 50-position ledger
Custom risk % presets
Closed-trade journal with realized R, win rate
Portfolio heat with cap warnings
Watchlist import (links & screenshots)
Google sync across devices + CSV export

Risk Calc is an educational position-sizing tool. Quotes via Finnhub. Everything here is informational only — not financial, investment, or trading advice, and not a recommendation to buy or sell any security. Trading involves risk of loss. You are responsible for your own decisions.

Help · how position sizing works

How position sizing works

Position sizing answers one question: how many shares can I buy so that if my stop loss hits, I only lose what I planned to lose? The formula is shares = account risk ($) ÷ stop size ($/share), where stop size is the distance between your entry price and your stop price. Risking 0.5% of a $10,000 account ($50) on a trade with a $2 stop size means a 25-share position — no matter how expensive the stock is.

What this tool does

Enter a ticker and Risk Calc streams the live price with a 1-minute candle chart, so you can watch momentum while entering orders at the open. Lock your stop to the low of day and both the stop and your position sizes update in real time as the low moves. The free tier shows 0.25%, 0.5%, and 1% account-risk tiers on one account and tracks up to three open positions in the ledger — no sign-up, everything stays in your browser. Risk Calc Pro sizes across as many accounts as you trade ("IRA", "Webull"), raises the ledger to 50 positions, and adds custom risk presets, a closed-trade R journal, portfolio heat, watchlist import, Google sync across devices, and CSV export.

Guides

Position sizing across multiple accounts — keeping risk consistent when you trade an IRA and a margin account side by side, and how a low-of-day stop drives your share count.

Built by Akuhl Consulting — practical software, systems, and automation. Need a custom tool like this for your business or trading workflow? Get in touch.

Position size calculator for swing trading