What is the Lot Size Calculator?
The Lot Size Calculator is a free online tool that helps you lot size from risk %, stop in pips It runs entirely in your browser, gives an instant result, and needs no sign-up, download or spreadsheet.
A pip is the standard unit a currency pair moves, and its cash value depends on your lot size — which is exactly why position sizing in forex starts with pip value.
Whether you trade stocks, forex, options, crypto or futures, the lot size is the same calculation — so this tool works for any market. Use it before you place a trade to base your decision on real numbers instead of a guess.
How to use the Lot Size Calculator
Using the lot size calculator takes only a few seconds:
- Enter your figures in the lot size calculator above — the fields are filled with an example you can replace.
- Read the highlighted result; it updates instantly as you type.
- Add your broker’s fees or commissions where relevant for a true net figure.
- Change any input to compare scenarios before you commit to the trade.
Lot Size formula & example
The lot size formula is: Lot size = risk amount ÷ (stop in pips × pip value).
One pip ≈ $1.00 per 0.1 lot. A 35-pip move on 0.1 lot = 35 × $1.00 = $35.00.
When to use the Lot Size Calculator
Reach for the lot size calculator whenever you’re planning a trade and need to know your lot size in advance. Running the number first keeps your decisions consistent and stops a single trade from doing outsized damage to your account. Traders who make this a habit — checking before every entry — are the ones who protect their capital over the long run.
Why use a lot size calculator?
Doing lot size by hand is slow and error-prone — a misplaced decimal or a forgotten fee can turn a winning plan into a losing one. The lot size calculator removes that risk: it applies the correct formula every time, updates the moment you change an input, and lets you test several scenarios in seconds.
That speed matters in live markets. When a setup appears you can size it, check the reward against the risk, and act before the opportunity passes — without second-guessing your arithmetic.
- Instant, accurate lot size with no spreadsheet
- Free, with no account, login or download
- Works on mobile and desktop, right in your browser
- Useful for stocks, forex, options, crypto and futures
Tips for accurate lot size
- Use your real entry, exit and size — not round-number guesses.
- Include fees and spread; small costs add up across many trades.
- Recalculate whenever your price, size or stop changes.
- Round against yourself to leave a margin for slippage.