> For the complete MongoDB documentation index, see www.mongodb.com/docs/llms.txt

# $toBool (expression operator)

## Definition

Converts a value to a boolean.

[`$toBool`](https://www.mongodb.com/docs/manual/reference/operator/aggregation/tobool.md#mongodb-expression-exp.-toBool) has the following syntax:

```javascript
{
   $toBool: <expression>
}
```

The [`$toBool`](https://www.mongodb.com/docs/manual/reference/operator/aggregation/tobool.md#mongodb-expression-exp.-toBool) takes any valid [expression.](https://www.mongodb.com/docs/manual/reference/mql/expressions.md#std-label-aggregation-expressions)

The [`$toBool`](https://www.mongodb.com/docs/manual/reference/operator/aggregation/tobool.md#mongodb-expression-exp.-toBool) is a shorthand for the following [`$convert`](https://www.mongodb.com/docs/manual/reference/operator/aggregation/convert.md#mongodb-expression-exp.-convert) expression:

```javascript
{ $convert: { input: <expression>, to: "bool" } }
```

**See also:**

[`$convert`](https://www.mongodb.com/docs/manual/reference/operator/aggregation/convert.md#mongodb-expression-exp.-convert)

## Behavior

The following table lists the input types that can be converted to a boolean:

| Input Type | Behavior |
| --- | --- |
| Array | Returns true |
| Binary data | Returns true |
| Boolean | No-op. Returns the boolean value. |
| Code | Returns true |
| Date | Returns true |
| Decimal | Returns true if not zeroReturn false if zero |
| Double | Returns true if not zeroReturn false if zero |
| Integer | Returns true if not zeroReturn false if zero |
| JavaScript | Returns true |
| Long | Returns true if not zeroReturn false if zero |
| MaxKey | Returns true |
| MinKey | Returns true |
| Null | Returns null |
| Object | Returns true |
| ObjectId | Returns true |
| Regular expression | Returns true |
| String | Returns true |
| Timestamp | Returns true |

To learn more about data types in MongoDB, see [MongoDB BSON Types.](https://www.mongodb.com/docs/manual/reference/bson-types.md#std-label-bson-types)

The following table lists some conversion to boolean examples:

| Example | Results |
| --- | --- |
| `{$toBool: false}` | false |
| `{$toBool: 1.99999}` | true |
| `{$toBool: Decimal128("5")}` | true |
| `{$toBool: Decimal128("0")}` | false |
| `{$toBool: 100}` | true |
| `{$toBool: ISODate("2018-03-26T04:38:28.044Z")}` | true |
| `{$toBool: "false"}` | true |
| `{$toBool: ""}` | true |
| `{$toBool: null}` | null |

## Example

Create a collection `orders` with the following documents:

```javascript
db.orders.insertMany( [
   { _id: 1, item: "apple",  qty: 5, shipped: true },
   { _id: 2, item: "pie",  qty: 10, shipped: 0  },
   { _id: 3, item: "ice cream", shipped: 1 },
   { _id: 4, item: "almonds", qty: 2, shipped: "true" },
   { _id: 5, item: "pecans", shipped: "false" },  // Note: All strings convert to true
   { _id: 6, item: "nougat", shipped: ""  }       // Note: All strings convert to true
] )
```

The following aggregation operation on the `orders` collection converts the `shipped` to a boolean value before finding the unshipped orders:

```javascript
// Define stage to add convertedShippedFlag field with the converted shipped value
// Because all strings convert to true, include specific handling for "false" and ""

shippedConversionStage = {
   $addFields: {
      convertedShippedFlag: {
         $switch: {
            branches: [
              { case: { $eq: [ "$shipped", "false" ] }, then: false } ,
              { case: { $eq: [ "$shipped", "" ] }, then: false }
            ],
            default: { $toBool: "$shipped" }
        }
      }
   }
};

// Define stage to filter documents and pass only the unshipped orders

unshippedMatchStage = {
   $match: { "convertedShippedFlag": false }
};

db.orders.aggregate( [
  shippedConversionStage,
  unshippedMatchStage
] )
```

The operation returns the following document:

```javascript
{ "_id" : 2, "item" : "pie", "qty" : 10, "shipped" : 0, "convertedShippedFlag" : false }
{ "_id" : 5, "item" : "pecans", "shipped" : "false", "convertedShippedFlag" : false }
{ "_id" : 6, "item" : "nougat", "shipped" : "", "convertedShippedFlag" : false }
```

**Note:**

If the conversion operation encounters an error, the aggregation operation stops and throws an error. To override this behavior, use [`$convert`](https://www.mongodb.com/docs/manual/reference/operator/aggregation/convert.md#mongodb-expression-exp.-convert) instead.