Math.floor and Math.round

JavaScript
1

I have been using Math.floor and Math.round many times but i think i failed to get the difference, can someone please help me identify the difference?

2

Math.round always rounds a number to the nearest integer. Look at the examples below:

  • 3.14 is between 3 and 4. But it is closer to 3 than 4. Therefore, Math.round(3.14) will return 3 because it is the nearest integer to 3.14
  • -3.14 is between -3 and -4. But it is closer to -3 than -4. Therefore, Math.round(-3.14) will return -3 because it is the nearest integer to -3.14
  • 3.94 is between 3 and 4. But it is closer to 4 than 3. Therefore, Math.round(3.94) will return 4 because it is the nearest integer to 3.94
  • -3.94 is between -3 and -4. But it is closer to -4 than -3. Therefore, Math.round(-3.94) will return -4 because it is the nearest integer to -3.94
  • Passing an integer to Math.round will return the integer

On the other hand, Math.floor rounds a number down to the nearest integer. It returns an integer less than or equal to the given number. Look at the examples below:

  • 3.14 is between 3 and 4. The closest integer less than or equal to 3.14 is 3. Therefore, Math.floor(3.14) will return 3
  • -3.14 is between -3 and -4. The closest integer less than or equal to -3.14 is -4. Therefore, Math.floor(-3.14) will return -4
  • 3.94 is between 3 and 4. The closest integer less than or equal to 3.94 is 3. Therefore, Math.floor(3.94) will return 3
  • -3.94 is between -3 and -4. The closest integer less than or equal to -3.94 is -4. Therefore, Math.floor(-3.94) will return -4
  • Passing an integer to Math.floor will return the integer

Given the examples above, Math.round rounds a number to the nearest integer. It rounds a number up if the nearest integer is greater and rounds it down if the nearest integer is less and returns the same number if you pass an integer. Math.floor will always round a number down to the nearest integer less than or equal to the given number.

I hope that helps.