> For the complete documentation index, see [llms.txt](https://docs.belugas.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.belugas.io/atokens/borrow.md).

# Borrow

The borrow function transfers an asset from the protocol to the user, and creates a borrow balance which begins accumulating interest based on the [Borrow Rate](/atokens/borrow-rate.md) for the asset. The amount borrowed must be less than the user's [Account Liquidity](/comptroller/get-account-liquidity.md) and the market's available liquidity.

To borrow Ether, the borrower must be 'payable' (solidity).

**BErc20 / CEther**

```
function borrow(uint borrowAmount) returns (uint)
```

* `msg.sender`: The account to which borrowed funds shall be transferred.
* `borrowAmount` : The amount of the underlying asset to be borrowed.
* `RETURN`: 0 on success, otherwise an [Error code](/atokens/error-codes.md)

**Solidity**

```
BErc20 bToken = BErc20(0x3FDA...);
require(bToken.borrow(100) == 0, "got collateral?");
```

**Web3 1.0**

```javascript
const bToken = CEther.at(0x3FDB...);
await bToken.methods.borrow(50).send({from: 0xMyAccount});
```


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://docs.belugas.io/atokens/borrow.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.