> For the complete documentation index, see [llms.txt](https://futuresdoc.gitbook.io/perp-doc/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://futuresdoc.gitbook.io/perp-doc/english-1/parameters/usds-margined-or-coin-margined-futures-contracts.md).

# USDⓈ-Margined  | Coin-Margined Futures Contracts

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**Note: USDⓈ-margined futures are also called forward contracts, and coin-margined futures are also called reverse contracts. It is difficult to understand reverse contracts, which can be understood by comparing parameters.**
{% endhint %}

## Introduction

### USDⓈ-margined futures contract

USDⓈ-margined futures, also known as forward contracts, is a contracts with stablecoins (such as USDT, BUSD, and USDC) as the quote and settlement currency.

### Coin-margined futures contract

Coin-margined futures, also known as inverse contracts, are contracts that use USD as the quote currency and the underlying currency (such as BTC, ETH, and LTC) as the settlement currency.

## Parameter comparison

<table><thead><tr><th width="189"> </th><th>USDⓈ-M (forward)</th><th>Coin-M (inverse)</th></tr></thead><tbody><tr><td>Contract Name</td><td>BTCUSDT</td><td>BTCUSD</td></tr><tr><td>Underlying Currency</td><td>BTC/USDT</td><td>BTC/USD</td></tr><tr><td>Index Price</td><td>BTC/USDT</td><td>BTC/USD</td></tr><tr><td>Pricing Currency</td><td>USDT</td><td>USD</td></tr><tr><td>Margin Currency</td><td>USDT</td><td>BTC</td></tr><tr><td>Revenue Currency</td><td>USDT</td><td>BTC</td></tr><tr><td>Contract Size</td><td>1 Cont. = 0.0001 BTC</td><td>1 Cont. = 1 USD</td></tr><tr><td>Order Quantity</td><td>n Cont. = 0.000n BTC</td><td>n Cont. = n USD</td></tr><tr><td>Position Value</td><td><p>= Cont. * size * opening price</p><p>Unit：USDT</p></td><td><p>= Cont. * size / opening price</p><p>Unit：BTC</p></td></tr><tr><td>Initial Margin</td><td><p>= Cont. * size * opening price / leverage</p><p>Unit：USDT</p></td><td><p>= Cont. * size / opening price / leverage</p><p>Unit：BTC</p></td></tr><tr><td>Profit Calculation (long positions)</td><td><p>= (Closing price - opening price) * Cont. * size</p><p>Unit：USDT</p></td><td><p>(1/opening price - 1/closing price) * Cont. * size</p><p>Unit：BTC</p></td></tr><tr><td>Profit Calculation (short position)</td><td><p>= (Opening price - closing price) * Cont. * size</p><p>Unit：USDT</p></td><td><p>= (1/closing price - 1/opening price) * Cont. * size</p><p>Unit：BTC</p></td></tr></tbody></table>

## A way of understanding reverse contracts

We can observe that the price in the reverse contract uses 1 / price, which can be understood as the price of USD/BTC, that is, 1 USD = 0.000x BTC.

If we put aside our daily concepts and swap the two currencies, for example, BTC is a fiat currency or stablecoins that people used every day, and USD is a digital currency. In this way, compared with forward contracts, we are trading USD/BTC. The quote currency BTC is used, and the size is also 1 USD. The number of positions opened is n USD, and the profit calculation also uses the forward contract (closing price - opening price) \* Cont. \* size, because the price = USD / BTC = 1 / (BTC/USD).

In this way, we are actually trading the USD/BTC forward contract, but this is not easy for users to understand, so we trade the price of BTC/USD in reverse, that is, the reverse contract.