MongoDB $lte Operator

What You’ll Learn

The $lte operator checks whether one value is less than or equal to another. Use it in $match to filter documents at or below a threshold, or in expression stages like $project and $cond to compare fields and get a true/false result.

Definition and Usage

In MongoDB, the $lte operator tests whether one value is less than or equal to another. In a $match stage, { age: { $lte: 20 } } filters documents where age is 20 or younger. In an aggregation expression, { $lte: [ "$price", 100 ] } returns true or false for each document. It pairs naturally with $gte for inclusive range queries.

📝 Syntax

$lte has two forms depending on where you use it:

Query form (in $match or find filters)

{ field: { $lte: <value> } }

Aggregation expression form (in $project, $cond, etc.)

{ $lte: [ <expression1>, <expression2> ] }

Syntax Rules

• Query form — filters documents where the field is less than or equal to the given value.
• Expression form — compares two expressions and returns true or false.
• Includes equals — values equal to the threshold match (unlike $lt).
• Works with numbers, dates, and strings (BSON comparison order).
• Use expression form inside $project, $addFields, $cond, and $filter.

Examples Gallery

Walk through sample student data, filter by age with $lte, and compare fields with the expression form.

[
  { "_id": ObjectId("609c26812e9274a86871bc6a"), "name": "Alice", "age": 20 },
  { "_id": ObjectId("609c26812e9274a86871bc6b"), "name": "Bob", "age": 25 },
  { "_id": ObjectId("609c26812e9274a86871bc6c"), "name": "Charlie", "age": 18 }
]

db.students.aggregate([
  {
    $match: {
      age: { $lte: 20 }
    }
  }
])

{ "_id": ObjectId("609c26812e9274a86871bc6a"), "name": "Alice", "age": 20 }
{ "_id": ObjectId("609c26812e9274a86871bc6c"), "name": "Charlie", "age": 18 }

db.orders.find({
  quantity: { $lte: 5 }
})

// quantity: 3  → included
// quantity: 5  → included (equals threshold)
// quantity: 8  → excluded

db.products.aggregate([
  {
    $project: {
      name: 1,
      price: 1,
      isAffordable: {
        $lte: [ "$price", 100 ]
      }
    }
  }
])

// price: 75  → isAffordable: true
// price: 100 → isAffordable: true
// price: 150 → isAffordable: false

db.inventory.aggregate([
  {
    $project: {
      item: 1,
      quantity: 1,
      status: {
        $cond: [
          { $lte: [ "$quantity", 10 ] },
          "low stock",
          "in stock"
        ]
      }
    }
  }
])

db.students.aggregate([
  {
    $match: {
      age: { $gte: 18, $lte: 25 }
    }
  }
])

// Alice (20)  → included
// Bob (25)    → included (25 ≤ 25)
// Charlie (18) → included (18 ≥ 18)

🚀 Use Cases

• Age and eligibility caps — find users at or below a maximum age or spending limit.
• Date filtering — select records on or before a deadline with { dueDate: { $lte: date } }.
• Threshold analysis — extract data points at or below performance or quality thresholds.
• Inclusive ranges — combine with $gte for bounded intervals that include both endpoints.

💡 Best Practices