# WHMCS\UsageBilling\Contracts\Metrics\UsageInterface

`Interface`

UsageInterface

## Methods

### collectedAt

```php
public function collectedAt()
```

**Returns** `Carbon`

### startAt

```php
public function startAt()
```

**Returns** `null\|Carbon`

### endAt

```php
public function endAt()
```

**Returns** `null\|Carbon`

### value

```php
public function value()
```

**Returns** `float`