What is Position Sizing?
Quick answer
Position sizing is deciding how much to put into a single trade, usually based on your account size and how much you are willing to risk. Done well, it caps the loss on any one trade to a small, planned share of your account, which is what keeps a losing streak from doing lasting damage. In copy trading, a sizing multiplier scales a trader’s position to fit your account.
Position sizing is the quiet decision behind every trade, and it matters more than picking winners. It answers a simple question: how much of your account goes into this one trade?
How position sizing works
A common approach ties the size of a trade to a fixed percentage of your account that you are willing to risk, along with the distance to your stop-loss. Risking a small, consistent fraction per trade means no single loss can do outsized damage, and it keeps your risk steady as your account grows or shrinks. A free position size calculator can turn your account size, risk percentage, entry, and stop into a share count.
Why position sizing matters in copy trading
When you copy a trader, you do not want to mirror their share count blindly, because their account is probably a different size than yours. Copy trading uses a sizing multiplier to scale each copied position to your account, plus hard limits like a maximum dollar per trade and total exposure caps. That is what lets a small account follow a large trader without being forced into oversized positions.
Frequently asked questions
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