Position Sizing: Calculating Lot Size and Risk per Trade
Originally published 2025-05-27. Translation and editorial review: 14 October 2026. Market figures refer to the original reporting period.
What is Position Size? Why is it important for professional traders?
One of the keys to survival in the Forex market is not finding the most accurate trade entry signals But it is risk management — And the heart of risk management is calculating the appropriate Position Size.
What is Position Size?
Position Size is the number of “lots” you open a market order for. which has a direct effect on
Size of profit/loss per price movement
Risk to the portfolio on each trade.
Simple example: If you open a Buy EURUSD order with 1.00 Lot (Standard Lot) → 1 pip movement = 10 USD profit/loss, but if 0.10 Lot → 1 pip = 1 USD.
Simple formula for calculating Position Size.
Position Size (lot)= Risk Money/(Stop Loss (pip)×Pip Value)
Original reference figure. Read it with the translated explanation and the original reporting date.
Description:
Risk Money = The amount you are willing to lose per stick (e.g. 2% of the portfolio).
Stop Loss (pip) = Your planned stop loss point in pips.
Pip Value = Value of 1 pip per 1 lot of the currency pair you trade.
Example of actual calculation
Information:
Port: 1000 USD
Allow 2% loss per trade → Risk Money = 20 USD
Stop Loss = 50 pips
Trade EURUSD → 1 Lot = 10 USD/pip
Import formula:
Lot= 20/(50×10)=0.04 Lot
You should open an order for only 0.04 Lot only.
3 Position Size mistakes that beginners often make.
❌ Open orders with the same lot size every time without looking at Stop Loss.
❌ Don't think that "big lot = big risk"
❌ Don't use a formula — trade based on your feelings or others.
Summary: Position Size controls the risk game.
Even if your trading system is not 100% accurate, if you can control your Position Size professionally, you will be in the market for a long time and still have the opportunity for continued growth.
"Risk control is more important than market predictions" — a maxim that world-class traders use every day.
Don't worry if the calculations are difficult. Our website has free calculating tools. Go to the Calculating Tools page. You can get it on this website. Reference
Share this post with your fellow traders. And don't forget to ask yourself:
Have you calculated your Position Size before trading today?
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