Position Size Calculators

Types of position size calculators

There are two browser-based position size calculators for stocks available on this page, created to help you calculate your position size of your total capital. The calculators are intended for equity traders who trade stocks.

Monetary risk calculator

The monetary risk position size calculator tells you how many shares you should buy, based on your desired monetary risk. Your monetary risk is the number of pounds you are risking on the trade.

Account risk calculator

The account risk calculator gives the number of shares to buy/sell as per your defined account risk. This is discretionary that you should consider for your own personal circumstances and risk/reward potential.

How to use the position size calculators

See the below instructions on how to use each position size calculator.

Monetary risk calculator

1. Enter your monetary risk (for example £500)
2. Input your entry price (for example 15p)
3. Put in your stop loss price which is the price you would close the trade (for example 11p)
4. You will now see the number of shares you should use to position size with (in this example 12,500 shares)

Account risk calculator

1. Enter your account size (for example £100,000)
2. Input your desired account risk (for example 5%)
3. Put in your entry price (for example 50p)
4. Type in your stop loss as defined by your methodology (for example 40p)

Understanding your monetary risk position size

Your position size is the maximum loss that you can take on the trade if the trade was to take a 100% loss.

Retail investor accounts are protected by European Securities & Markets Authority MiFID-II legislation which protects retail accounts from negative equity.

This means that unless you are a professional trader the maximum loss on any leveraged trade is 100% on any given trade.

Shares

The shares refers to the number of shares you trade in order to calculate your position size. This varies according to your trading or investment objectives.

Cost

The cost refers to the entry price of the position. As detailed above, this is the purchase price if you are long or the sale price if you are short selling.

Risk per share

The risk per share is simply the entry price minus the stop price. In the example given, the entry price is 15p and the stop loss is 11p. That means our risk per share is 4p (15p – 11p = 4p).

Understanding your account risk position size

Your account risk is calculated by inputting your total account size and the risk amount of your trading account. To do this, you need to put in your entry price and your stop-loss level.

For example, if your account equity is £100,000 and you are willing to risk 5% of that on a trade, then the account risk calculator will tell you the number of shares to buy for your specific needs.

I have my position size, now what?

Your position size tells you the position you should take on the trade based on your monetary risk. If you decide to change your stop loss price once you have entered the trade then this will change your monetary risk. Please be aware of this when altering stops.

Frequently asked questions

Need additional help? See how to find the relevant metrics for the position size calculators.

What is stock position size?

Your position size is the number of shares that you trade multiplied by the share price. It is the total monetary value in GBP of the position. In forex trading, your position size is the lot size you take on a particular trade. However, this is not a forex position size calculator.

How do you calculate position size?

Position size is calculated by taking the monetary risk on the trade and dividing this by the risk per share. Your risk per share is the entry price of the trade minus the stop loss price.

How do you calculate monetary trade risk?

Monetary trade risk is a part of proper risk management. Any trader should know the maximum amount they are willing to risk on the trade.

This is known as the monetary trade risk.

Calculating this is discretionary and dependent on how much risk you wish to take. Some traders are not comfortable risking more than 1% on the trade. Other traders are happy to take on higher risks. This depends on your own risk tolerance limits.

However, the size of the position will be determined by the monetary trade risk and the risk per share.

Trade risk is not the same as account risk. Account risk is the total position size which will be defined by the number of contracts or shares multiplied by the share price.

The account risk is the total damage that can be done to your trading account’s equity if the position were to go to a 100% loss.

How do you calculate account size?

Your account size is the total equity of your trading account (or fixed dollar amount if you’re US based).

It is the number that you can use which determines how much risk you take in your trades.

How do you calculate account trade risk?

Account trade risk is the percentage of your account size that you’re willing to risk on the trade.

For example, if you wanted to risk 5% of your account on one trade, meaning you can be wrong 20 times before blowing your account, then you would need to put 5% in this box.

How do I find the entry price?

The entry price is the price that you would pay by entering the trade. This is different to the share price.

The share price is the mid-price of the bid-ask spread. When buying, we pay prices towards the asking price (or full ask price), and when shorting we pay prices towards the bid price (or full price).

For example, if you are positioning long, then the entry price would be your purchase price.

How do you calculate stop loss?

The stop loss is the price that you want to exit the trade. Professional traders focus on risk management and have levels they wish to get out of the market at should the price turn against them.

Those who trade without stops eventually stop trading. Not using stop losses (either physical or mental) means the trade takes on a high level of risk.

You should look at the chart and decide where you wish to exit the trade.

Risk disclaimer: This position size calculator is to be used for informational purposes and is a guideline only. It is not investment advice. It is intended for equities and not options trading, spot forex, or any spot currency trading.

This position size calculator cannot be held responsible for any loss of profit and is to be used at your own risk.

There is no guarantee of the accuracy and so you should double-check this before taking a position. Any mistakes (especially with leverage and borrowed money) may see a large potential risk on the trade.

This calculator is for stock investors only and is not intended for currency pair usage although the units may be able to used interchangeably with pips, pip value, standard lot, mini lots, and micro lots.

Any use of leverage (especially a high degree of leverage) should come with a high risk warning.

Remember, all financial products can come with a substantial risk of loss. The past performance of any trading system is never guaranteed no matter the size of the large potential rewards.