How is the liquidation price of a perpetual contract calculated? Understand isolated and cross margin modes in one article

The biggest fear when trading futures is sudden liquidation. But actually, the liquidation price has a formula. As long as you calculate this number clearly, you’ll have a better grasp of your risk. Today, let’s break down the logic behind it.

When will you be liquidated?

Simply put: when your margin is insufficient to maintain your position, the system will automatically close your position. For example, if you go long 1 BTC at 20,000 USDT using 50x leverage, and BTC drops to 19,700 USDT, you’ll be liquidated.

Isolated Margin Mode (More Controllable Risk)

In this mode, each position’s margin is independent. The most you can lose is the margin you put into that position, and it won’t affect your entire account.

Long position liquidation price formula: Liquidation Price = Entry Price - [(Initial Margin - Maintenance Margin) / Contract Quantity]

Example:

• You go long 1 BTC at 20,000 USDT with 50x leverage
• Initial Margin = 20,000 ÷ 50 = 400 USDT
• Maintenance Margin = 20,000 × 0.5% = 100 USDT
• Liquidation Price = 20,000 - (400 - 100) = 19,700 USDT

If you add an extra 3,000 USDT margin midway, your liquidation price becomes much safer.

Cross Margin Mode (Flexible but Risky)

In this mode, all positions share your account balance. Losses in one position can eat into the margin of other positions, and risks are interconnected.

Core Logic: Liquidation Price = Entry Price ± [(Available Balance + Initial Margin - Maintenance Margin) / Net Position]

Real-world scenario: Suppose you have 2,000 USDT available balance and go long 2 BTC at 10,000 USDT using 100x leverage.

• Initial Margin = (2 × 10,000) ÷ 100 = 200 USDT
• Available balance becomes 1,800 USDT
• Maximum loss you can bear = 1,800 - 100 (Maintenance Margin) = 1,700 USDT
• Loss per BTC = 1,700 ÷ 2 = 850 USDT/BTC
• Liquidation Price = 10,000 - 850 = 9,150 USDT

Key Trap: Liquidation Price Changes with Multiple Positions

Suppose you hold:

• BTC long: 1 BTC, entry at 20,000, losing 500 USDT
• ETH short: 10 ETH, entry at 2,000, gaining 100 USDT
• Account balance: 3,000 USDT

BTC’s liquidation price is not only affected by the BTC position but also by losses on ETH. Whenever one position’s loss increases, the liquidation prices of other positions get closer. This is the “chain reaction” of cross margin.

Three Tips to Avoid Pitfalls

1. Use isolated margin for high-risk trades — Losses won’t affect other positions
2. Keep enough backup funds in cross margin — Prevent one position’s crash from causing chain liquidations
3. Calculate your liquidation price — Work it out before placing an order, not after it’s too late