Lot Size Calculator

How many lots should you trade?

In forex, position size is measured in lots: a standard lot is 100,000 units of the base currency, a mini lot is 10,000, and a micro lot is 1,000. This calculator works out the lot size that keeps your loss to a fixed percentage of your account if your stop-loss is hit — the core of responsible forex risk management.

The formula

• Amount at risk = balance × risk %.
• Lots = amount at risk ÷ (stop-loss in pips × pip value per standard lot).

For most USD-quoted pairs (EUR/USD, GBP/USD, AUD/USD), one pip on a standard lot is worth about $10. JPY pairs and pairs not quoted in your account currency differ, so adjust the "pip value per standard lot" field to match your broker's figure.

FAQ

What's a pip?

A pip is the standard smallest price move — the 4th decimal for most pairs (0.0001), or the 2nd decimal for JPY pairs (0.01). Your stop-loss distance in pips, times the pip value, times your lots, equals your dollar risk.

How much of my account should I risk per trade?

Many traders cap risk at 1–2% of their account balance per trade, so a single loss is survivable and a losing streak doesn't wipe out the account. Enter your chosen percentage and the calculator sizes the position to keep the loss within that limit if your stop is hit.

What lot size should I use for JPY pairs?

JPY pairs use a pip value that differs from the usual $10 per standard lot because the pip is the 2nd decimal and the yen conversion matters. Replace the "pip value per standard lot" field with the figure your broker shows for that pair so the lot size comes out correct.

Why is my calculated lot size a fraction?

The result is the exact size that matches your risk, which often falls between whole lots — for example 0.27 lots. Most brokers accept two-decimal lot sizes (down to 0.01), so round to the nearest size your platform allows, rounding down to stay within your risk.

Is this calculator free and private?

Yes — it's free with no sign-up, works on mobile, and runs entirely in your browser, so your balance and trade details are never sent anywhere.

Educational tool only — not financial advice. Confirm pip values with your broker.