How to count the number of documents in a MongoDB collection?

Following is the syntax to count the number of documents in a MongoDB collection

let anyVariableName= db.getCollection(‘yourCollectionName’); yourVariableName.count();

Let us first create a collection with documents

> db.countNumberOfDocumentsDemo.insertOne({"CustomerName":"Bob"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5c9a5e2015e86fd1496b38a1") } >db.countNumberOfDocumentsDemo.insertOne({"CustomerName":"Ramit","CustomerAge":23}); {    "acknowledged" : true,    "insertedId" : ObjectId("5c9a5e3515e86fd1496b38a2") } >db.countNumberOfDocumentsDemo.insertOne({"CustomerName":"Adam","CustomerAge":27,"CustomerCountryName":"US"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5c9a5e4c15e86fd1496b38a3") }

Following is the query to display all documents from a collection with the help of find() method

> db.countNumberOfDocumentsDemo.find().pretty();

This will produce the following output

{ "_id" : ObjectId("5c9a5e2015e86fd1496b38a1"), "CustomerName" : "Bob" } {    "_id" : ObjectId("5c9a5e3515e86fd1496b38a2"),    "CustomerName" : "Ramit",    "CustomerAge" : 23 } {    "_id" : ObjectId("5c9a5e4c15e86fd1496b38a3"),    "CustomerName" : "Adam",    "CustomerAge" : 27,    "CustomerCountryName" : "US" }

Following is the query to count the number of documents in a MongoDB collection,

> let myCollectionName = db.getCollection('countNumberOfDocumentsDemo'); > myCollectionName.count();

This will produce the following output

3