Traders who open contracts often encounter a question: should they choose cross margin or isolated margin? These two modes seem simple, but in reality, they differ greatly and directly impact your risk control and profit potential.

First, let's talk about the concept of margin. The money needed to open a position is called the initial margin, and the minimum amount to maintain the position is called the maintenance margin. Many beginners can't distinguish these two; in fact, it's the difference between opening and holding a position.

In cross margin mode, all available balance in your account can be used as margin. If the position incurs a loss, the system will automatically top up from your account, continuously adding as long as there is money. This sounds good, but the problem is: if the market moves sharply, your entire account could be wiped out.

Isolated margin is different. The margin for each position is independent, and losses only affect that position. The system won't automatically add funds unless you do it manually. This means your maximum loss is limited to the margin of that position and won't affect other funds. That's why many cautious traders prefer the isolated margin mode.

Here's a real example. Suppose you and a friend each have $2,000, and both open a 10x leveraged long position on BTC. You choose isolated margin, and he chooses cross margin.

If the market drops to the liquidation price, your $1,000 is liquidated, losing $1,000, leaving your account with $1,000. He, using cross margin, also loses $1,000, but the system automatically tops up, so his position remains. If BTC rebounds, he can turn losses into gains; but if it continues to fall, he might lose all $2,000.

This is the core difference between cross and isolated margin. Cross margin has stronger loss resistance and is easier to operate, but during major market moves, the risk is enormous. Isolated margin risk is controllable, but you need to manage your margin actively and can't be lazy.

The formulas for calculating liquidation risk are also different. For isolated margin, it's the maintenance margin divided by the position margin times 100%. For cross margin, it's the maintenance margin divided by available balance plus position margin times 100%. When risk reaches 70%, a warning is issued; exceeding 100% results in immediate liquidation.

The calculation method for position margin is: position value divided by leverage plus additional margin minus reduced margin plus unrealized profit and loss. It looks complicated, but exchanges will calculate it automatically; you just need to understand the logic.

Generally, if a beginner has limited risk tolerance, isolated margin is a safer choice because a single position's liquidation won't affect other funds. Experienced traders might choose cross margin based on market conditions to improve capital efficiency. But regardless of the mode, strict stop-loss and risk management are always the top priorities. Some platforms default to cross margin, but both modes can reach up to 100x leverage. When placing orders, remember not to switch modes or change leverage.