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

# Underlying Balance

The user's underlying balance, representing their assets in the protocol, is equal to the user's aToken balance multiplied by the [Exchange Rate](/atokens/exchange-rate.md).

**SErc20 / SEther**

```
function balanceOfUnderlying(address account) returns (uint)
```

* `account`: The account to get the underlying balance of.
* `RETURN`: The amount of underlying currently owned by the account.

**Solidity**

```
SErc20 aToken = SToken(0x3FDA...);
uint tokens = aToken.balanceOfUnderlying(msg.caller);
```

**Web3 1.0**

```
const aToken = SEther.at(0x3FDB...);
const tokens = await aToken.methods.balanceOfUnderlying(account).call();
```