How to Calculate Position Size for Trading?

How to Calculate Position Size for Trading

Understanding Position Sizing

Understanding the importance of position sizing in trading requires grasping the concepts of risk management and money management. These principles help us see why position sizing is crucial in trading.

If you fail to calculate the size of your positions in trades, it becomes impossible to accurately measure the level of risk you’re taking on.

Position sizing involves figuring out the right number of shares or units to buy in a trade and the best way to acquire them, all based on managing your money and risks.

The aim of position sizing is to allocate the perfect amount of money to each trade, taking into account factors like your account size, how much risk you’re comfortable with, your trading strategy, and the current market conditions.

Position sizing isn’t just about the quantity of units you buy; it also includes how you make the purchase. This could mean buying all units at once, splitting orders and buying at different prices, or exiting the position in one go or in parts at various price levels.

In this discussion, we’ll focus on simple position sizing methods because more advanced techniques depend on the strategy being used. We’ll cover those advanced methods in detail when we look at different strategies.

In trading, including position sizing, there are different approaches that work best depending on the specific strategies and situations involved. It’s important to understand that one method won’t work for all strategies or assets. Different strategies and situations may need different approaches that work better for them.

Position Sizing Methods

As said earlier, there are many ways to calculate position size for your trades, and here are the most used methods.

Fixed Dollar Amount:

In this method, traders allocate a fixed dollar amount or percentage of their trading capital to each trade. For example, a trader with a $10,000 account may decide to risk 1% ($100) on each trade. This approach ensures consistency in position sizing but may not account for variations in volatility or risk.

Percentage of Capital:

With this method, traders risk a fixed percentage of their trading capital on each trade. For instance, a trader may choose to risk 2% of their account on every trade. As the account size fluctuates, the position size adjusts accordingly, providing a dynamic approach to risk management.

Volatility-Based Position Sizing:

This method takes into account the volatility of the asset being traded. By incorporating measures such as the Average True Range (ATR) or standard deviation, traders adjust their position sizes to reflect the inherent volatility of the market. This approach ensures that position sizes are proportional to the level of risk present in each trade.

Simple Position Sizing for Stocks

This basic approach to position sizing lays a solid foundation. Once you understand this concept, you’re ready to explore more advanced methods.

Though I’ll demonstrate this technique using stocks, it’s worth noting that you can use the same strategy for other assets too.

This strategy revolves around one entry point to start a trade, one exit point to take profits, and another exit point to cut losses if the trade moves against you.

Here’s a step-by-step guide on how to calculate position size:

Determine Your Risk Tolerance:

Before calculating the position size, it’s crucial to establish your risk tolerance.

This is the maximum amount of capital you are willing to risk on a single trade, typically expressed as a percentage of your account balance or a fixed monetary amount.

This is where money management comes in.

Set Your Stop Loss Level:

A stop-loss order is a predetermined price level at which you will exit the trade to limit potential losses.

Determine where you will place your stop-loss order based on your trading strategy, technical analysis, or other risk management considerations.

Stop-loss orders are determined by utilizing both risk management principles and technical analysis.

Calculate the Risk per Trade:

The risk per trade is the maximum amount of capital you are willing to lose if the trade goes against you and hits the stop-loss level. It’s your risk tolerance.

For example, if you’re willing to risk 2% of your $10,000 account, your risk per trade would be $200 (2% * $10,000).

Calculate the Difference Between Entry and Stop Loss Levels:

Determine the difference in price between your entry point and the stop-loss level.

For example, if you enter a trade at $50 per share and set the stop-loss at $45 per share, the difference would be $5 per share.

Calculate the Position Size:

Position Size = (Max loss per trade) / (Amount you can lose per unit)

To calculate the position size, divide the risk per trade by the difference between the entry and stop-loss levels.

This will give you the number of shares, contracts, or units you should trade.

For example, if your risk per trade is $200 and the price difference is $5 per share, your position size would be 40 shares ($200 / $5).

Position Sizing for Forex

When dealing with forex, it is necessary to determine the pip value and then multiply it by the number of pips between your stop-loss level.

Determine the Pip Value:

In Forex, the value of a pip represents the smallest incremental movement in a currency pair.

The pip value varies based on the currency pair and the lot size.

A quick shortcut to determine the pip value in trading is to multiply the number of lots you’re trading by 10. This simple calculation gives you the pip value. but you don’t need this because we gonna use a calculator for this job.

You can refer to a pip calculator or use your trading platform to determine the pip value for the currency pair you are trading. for more information about forex you can check here.

Calculate the Position Size:

To calculate the position size in Forex, divide the risk per trade by the number of pips between your entry point and stop-loss level, adjusted by the pip value. This will give you the lot size for the trade.

For example, if your risk per trade is $200, the number of pips is 50, and the pip value is $10, your position size would be 0.4 lots ($200 / (50 pips * $10)).

There are many online calculators available for determining position sizes in forex trading.

myfxbook position size calculator is one of them. this is the simplest and easiest way to do it.


By accurately calculating the position size, you can determine the precise number of shares or units to buy in order to limit potential losses to your predetermined maximum. Getting your position size right is crucial. It helps you control risk and make the most of your trading opportunities. Buying too many shares could result in greater losses than intended, while buying too few shares may mean missing out on optimal opportunities.