Isolated vs Cross Margin: The Setting That Saves Accounts

One dropdown on the order panel decides whether a bad trade costs you a position or an account. Margin mode is the least glamorous setting in futures trading and one of the most consequential. Here is exactly what each mode does, with the failure cases spelled out.

Isolated Margin: The Firewall

In isolated mode, you assign a specific amount of margin to a position, and that amount is the absolute maximum the trade can lose. If the market blows through every level and the position is liquidated, you lose the assigned margin and nothing else. Your remaining balance sits untouched, ready for the next trade.

The cost of the firewall is rigidity: because only the assigned margin defends the position, the liquidation price sits closer than it would in cross mode with the same account. You can add margin manually to push liquidation away, but that is a deliberate action, not an automatic drain.

Cross Margin: The Shared Pool

In cross mode, your entire available balance backs all cross positions collectively. A losing position automatically pulls from the shared pool to avoid liquidation, which keeps it alive through deeper drawdowns. That sounds like a feature until you follow the logic to its end: the position stays alive by consuming the account. When cross liquidation finally hits, it does not take one trade's margin. It takes everything backing the pool.

Side by Side

The Failure Story Worth Internalizing

The classic cross margin disaster goes like this. A trader opens a long with 10 percent of their account, on cross without thinking about it. The market drops. Instead of dying at the isolated liquidation point, the position keeps borrowing from the balance, and the trader, seeing the position still alive, holds. The drop continues. By the time liquidation triggers, the position has consumed the full balance. A trade that should have cost 10 percent cost 100. Nothing about the market changed between those outcomes; only the margin mode did.

Our Recommendation

• Default to isolated margin on every directional trade, at any experience level.
• Decide margin per position with the sizing formula from the leverage guide: risk about 1 percent of the account per trade.
• Reserve cross margin for the day you run genuinely hedged positions and can explain exactly why the shared pool helps you.
• Whichever mode you use, the stop loss is your real exit. Liquidation mechanics, covered in the liquidation guide, are the backstop you never intend to touch.

When Cross Margin Actually Makes Sense

Cross margin earns its place in exactly one situation: positions that offset each other. A trader who is long ETH and short BTC as a relative value pair wants profits on one leg to support margin on the other automatically; forcing each leg into its own isolated wall would require constant manual rebalancing. The same logic applies to hedging a spot portfolio with a short perpetual. Notice what these cases share: the positions are designed as a set, total exposure is capped by construction, and the trader monitors the book as one unit. A single directional bet on cross margin shares none of those properties; it is just an account sized stop loss you never agreed to.

How Margin Mode Interacts with Position Sizing

Isolated margin makes the risk formula honest. When you assign 200 USDT to an isolated position, the worst case is exactly 200 USDT, so risking 1 percent of a 10,000 USDT account means the assigned margin, not some estimate, obeys the limit. On cross, your true risk per trade is a function of every other open position and the balance behind them, which makes per trade risk accounting nearly impossible for a discretionary trader. If you follow the sizing method in our risk management rules, isolated margin is what makes the numbers mean what you think they mean.

Changing Margin Mode in Practice

On Bitunix and most major exchanges, margin mode and leverage sit together above the order panel: select the contract, tap the isolated or cross selector, set leverage, and the choice applies to new positions on that contract. Two habits worth building from day one: verify the mode before every entry on a contract you have not traded recently, since settings persist per market, and never switch an underwater position to cross to postpone liquidation. That move converts a contained loss into an account level bet at the exact moment your judgment is worst.