Kotlin – Get File Size

Kotlin – Get File Size

To get the file size in Kotlin, you can use length() method of java.io.File class.

In this tutorial, we shall see a step by step guide on how to get the size of a file in Kotlin, and an example program to get the size of 'example.txt' file.

Steps to get the File Size in Kotlin

The following is a step by step process to get the size of a file, where the file is given by a filePath.

  1. Import java.io.File class.
  2. Consider that the file path is given in the filePath variable, whose size we would like to find.
  3. Create a File object by passing the filePath.
  4. Check if the file exists using the exists() method of the File object.
  5. If the file exists, use the length() method to get the size of the file in bytes.
  6. Print the file size.

Example Program to read ‘example.txt’ to a string

In this example, we have a text file example.txt which we like to get the size of.

Kotlin - Get File Size - 62 bytes
Input file – example.txt


import java.io.File

fun main() {
    val filePath = "example.txt" // Replace with the path to your file

    val file = File(filePath)

    if (file.exists()) {
        val fileSize = file.length()
        println("File size: $fileSize bytes")
    } else {
        println("The file '$filePath' does not exist.")


File size: 62 bytes


Summarizing this Kotlin File Operations tutorial, we have seen how to get the file size using java.io.File.length() method, with a well detailed step by step process, and an example program.