Perpetual Futures Explained: How Crypto Perps Work

Perpetual futures, often called perps, are derivative contracts that track the price of a crypto asset but never expire, letting traders hold leveraged long or short positions indefinitely. A recurring payment between longs and shorts, called the funding rate, keeps the contract's price close to the spot price of the asset.

Perpetuals are the most heavily traded products in crypto by volume, offered on both centralized exchanges and decentralized platforms. They are powerful tools for hedging and speculation, but leverage and liquidation make them easy to misuse. This guide explains the mechanics step by step.

Where Perpetual Futures Came From

Traditional futures contracts expire on a fixed date, at which point they settle and traders must roll into a new contract. Crypto exchange BitMEX introduced the perpetual swap in 2016 as a contract without expiry, combining the simplicity of spot trading with the leverage of futures. The design spread across almost every major crypto exchange and later to decentralized exchanges.

How Perpetual Futures Work

Opening a position

You choose a market, such as BTC-USDT perpetual, decide long or short, set your position size and post margin. If you open a $5,000 position with $500 margin, you are using 10x leverage.

Profit and loss

Your profit or loss tracks the change in price. A long position gains when the price rises; a short position gains when it falls. Unrealized profit and loss is calculated using the mark price.

Margin types

Maintenance margin and liquidation

Each position needs a minimum amount of margin to stay open, called maintenance margin. If losses push your margin below that level, the exchange closes the position. With high leverage, the liquidation price can be very close to your entry price. Learn more in leverage in crypto trading.

The Funding Rate

Because perps never expire, nothing forces their price to converge with spot. The funding rate solves this:

• When the perp trades above spot, funding is usually positive: longs pay shorts. This encourages shorting and discourages longs, pulling the price down toward spot.
• When the perp trades below spot, funding is usually negative: shorts pay longs.

Funding is exchanged directly between traders, not paid to the exchange. Many exchanges apply it every eight hours, though intervals vary. Funding can look small per period but adds up over days and weeks. See funding rates explained for worked examples.

Traders also watch funding as a sentiment indicator: persistently high positive funding suggests many traders are leveraged long.

Mark Price, Index Price and Last Price

Using a mark price instead of the last trade helps protect traders from liquidations caused by brief spikes or manipulation on one exchange.

Example: A Leveraged Long

1. 1Bitcoin trades at $60,000 (illustrative).
2. 2You open a $6,000 long with $600 margin at 10x leverage.
3. 3If bitcoin rises 5%, your position gains about $300, a 50% return on margin before fees and funding.
4. 4If bitcoin falls 5%, you lose about $300, half your margin.
5. 5If it falls further toward roughly 9–10%, you approach liquidation, depending on the exchange's maintenance margin.

The leverage that doubles profits is the same leverage that wipes out margin.

Centralized vs Decentralized Perps

Perpetuals trade on large centralized exchanges and on decentralized perpetual exchanges that run on blockchains. Decentralized versions let you keep custody until you deposit margin into a smart contract, but they add smart-contract and oracle risk. Read decentralized perpetual exchanges explained.

Risks of Perpetual Futures

1. 1Liquidation. High leverage leaves little room for normal volatility.
2. 2Funding costs. Holding a crowded position for long periods can be expensive.
3. 3Liquidation cascades. Forced selling in crowded markets can push prices sharply, triggering more liquidations. See liquidation cascades.
4. 4Auto-deleveraging. In extreme conditions, some exchanges reduce profitable traders' positions to cover losses that the insurance fund cannot.
5. 5Platform risk. Funds on an exchange are exposed to hacks, outages and insolvency.
6. 6Legal restrictions. Many countries restrict retail access to leveraged crypto derivatives.

Open Interest and What It Tells You

Open interest is the total number of perpetual contracts outstanding at a given time. Rising open interest means new positions are being opened, while falling open interest means positions are being closed or liquidated. Traders often look at open interest together with funding rates and price to judge how crowded a market is.

For example, rising prices with rising open interest and strongly positive funding suggests many traders are leveraged long, which can make the market vulnerable to a sharp drop if sentiment turns. Read open interest explained for more.

Practical Safety Rules

• Know your liquidation price before entering.
• Use low leverage, or none, while learning.
• Prefer isolated margin to cap losses per trade.
• Check funding before holding positions for days.
• Never add margin to a losing trade without a clear plan.
• Use only platforms permitted in your country.

Bottom line

Perpetual futures give traders leveraged exposure to crypto prices without an expiry date, with funding payments keeping prices near spot. They are efficient tools for hedging and short-term trading, but leverage, liquidation and funding make them unforgiving. If you are new, learn spot trading and risk management first, and treat perps as an advanced instrument.