# 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](https://docs.agilefi.org/atokens/exchange-rate).

**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();
```