Two margin modes, fundamentally different risk profiles
Every perpetual futures platform offers two margin modes: isolated and cross. The choice between them determines the maximum amount you can lose on any single position — and whether a losing trade can cascade into losses on your other positions or your entire account balance.
This is not a minor technical setting. It is one of the most consequential decisions a perpetual futures trader makes — and most new traders leave it at the platform default without understanding what it means.
New to perps? Start here → What Are Perpetual Futures?
Isolated margin — how it works
In isolated margin mode, you allocate a specific, fixed amount of margin to each position when you open it. That allocated margin is the only collateral supporting that position.
If the position moves against you and the allocated margin is exhausted, the position is liquidated. The liquidation stops there. Your other positions and the rest of your account balance are untouched.
Example: $10,000 account, isolated margin, $500 allocated to a BTC long at 10x leverage.
- ·Position size: $5,000 notional
- ·Maximum loss: $500 (the isolated margin)
- ·If BTC drops 10% and the position liquidates: lose $500, keep $9,500
- ·Other open positions: unaffected
The tradeoff: because the position only has access to its allocated margin, it is more likely to be liquidated during a volatile move. There is no buffer from the rest of your account. If you want to give a position more room, you must manually add margin to it.
Cross margin — how it works
In cross margin mode, all open positions share your entire account balance as collateral. When a position moves against you, the exchange draws from your total available balance — not just the margin originally allocated to that position.
This means a position that would have been liquidated under isolated margin can survive longer under cross margin, because the exchange pulls additional funds from your account to keep it open.
Example: $10,000 account, cross margin, BTC long position moving against you.
- ·Position moves against you — losses exceed initial margin allocation
- ·Exchange draws from remaining $9,500 account balance to keep position open
- ·If losses continue: entire account balance can be consumed before liquidation
- ·Worst case: total account wipeout from a single position
Cross margin also creates cascading risk across positions. If you are long BTC and short ETH simultaneously in cross margin, a large adverse move in BTC draws from the same pool of collateral supporting the ETH position. Both positions can be at risk from a move in one asset.
Direct comparison
- ·Maximum loss per position: Isolated — allocated margin only · Cross — entire account balance
- ·Liquidation trigger: Isolated — when allocated margin exhausted · Cross — when total account balance exhausted
- ·Impact on other positions: Isolated — none · Cross — draws from shared collateral
- ·Cascading risk: Isolated — impossible · Cross — a move in one asset affects all positions
- ·Position survival in volatile moves: Isolated — lower (less buffer) · Cross — higher (more buffer, but more dangerous)
- ·Account wipeout from single trade: Isolated — impossible · Cross — possible
- ·Best for: Isolated — most retail traders, systematic strategies · Cross — experienced traders managing hedged portfolios
When cross margin makes sense
Cross margin is not always wrong. There are legitimate use cases — primarily for experienced traders with specific hedging strategies.
- ·Hedged positions: if you are long spot BTC and short BTC perpetuals as a hedge, cross margin allows the hedge to absorb adverse moves without triggering isolated liquidations on either side.
- ·Market-making strategies: traders simultaneously managing many positions on both sides of the book may use cross margin to avoid constant isolated margin management.
- ·Portfolio-level risk management: when the entire account is managed as one integrated position rather than individual trades.
In all of these cases, the trader understands cross margin mechanics deeply and is actively managing the risk. These are not beginner use cases.
The default for most retail traders: isolated margin
For the vast majority of retail perpetual futures traders — especially those following a systematic strategy — isolated margin is the correct default. Every time.
The reasons are straightforward:
- ·Hard loss cap per trade. Combined with a stop loss, isolated margin creates two independent layers of protection. The stop loss closes the position at your defined exit. If the stop fails to fill (slippage in a fast market), isolated margin caps the loss at your allocated margin. Cross margin removes this second layer.
- ·No cascade risk. A losing trade in isolated margin cannot affect other open positions. In cross margin, an unexpected large loss in one position can push other positions toward liquidation simultaneously.
- ·Clear risk accounting. With isolated margin, you know exactly what you stand to lose before you open the trade. With cross margin, the answer is "up to my entire account balance" — which is not a risk you can plan around.
- ·Psychological discipline. Isolated margin prevents the "let it recover" response. When the allocated margin is exhausted, the position closes. The decision is made by the rules, not by emotion in the moment.
Switching margin modes
Most exchanges allow you to switch between isolated and cross margin — but only when no position is open in that contract. You cannot switch margin modes on an existing open position.
Check your margin mode before opening every position — especially if you use an exchange where cross margin is the default. Platforms vary:
- ·Some exchanges default to cross margin — verify before your first trade
- ·Some exchanges remember your last setting per contract — a cross margin session yesterday may have left cross as the default today
- ·Some exchanges apply margin mode per contract — BTC perp and ETH perp can have different margin modes simultaneously
The check takes five seconds. Make it a pre-trade habit — every session, every contract.
The complete pre-trade risk checklist → Perpetual Futures Risk Management
How liquidation is calculated → The Math of Perpetual Futures Liquidation