Random number examples in javascript.

Here you find common examples of random numbers in javascript.

Random number from 0.000000... to 0.999999...

Includes 0.0, Excludes 1.0

Math.random()
0.5653749472719645
Math.random()
0.18129516667898726
Math.random()
0.38332031525383603
Math.random()
0.11096588528106843
Math.random()

Random integer from 0 to 9

Includes integer 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9.

Math.floor(Math.random() * 10)
7
Math.floor(Math.random() * 10)
6
Math.floor(Math.random() * 10)
9
Math.floor(Math.random() * 10)
0
Math.floor(Math.random() * 10)
7

Random integer from 1 to 10

Includes integer 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10.

Math.floor((Math.random() * 10) + 1)
10
Math.floor((Math.random() * 10) + 1)
5
Math.floor((Math.random() * 10) + 1)
6
Math.floor((Math.random() * 10) + 1)
4
Math.floor((Math.random() * 10) + 1)
10
Math.floor((Math.random() * 10) + 1)
1

Random integer 0 or 1

Generates the two integers 0 and 1.

Math.floor((Math.random() * 2))
1
Math.floor((Math.random() * 2))
1
Math.floor((Math.random() * 2))
0
Math.floor((Math.random() * 2))
0
Math.floor((Math.random() * 2))
0
Math.floor((Math.random() * 2))
1
Math.floor((Math.random() * 2))
0

Random boolean

Use the double equals operator to get the truthy value from 0 and 1:

Math.floor((Math.random() * 2)) == true
false
Math.floor((Math.random() * 2)) == true
false
Math.floor((Math.random() * 2)) == true
true
Math.floor((Math.random() * 2)) == true
true
Math.floor((Math.random() * 2)) == true
false

Random integer between two integer values

Get a random integer from (including) a minimum integer to (including) a max integer.

This code generates integers in range: 2, 3, 4, 5, 6 and 7

const min = 2;
const max = 7;
Math.floor((Math.random() * (max - min + 1)) + min)
4
Math.floor((Math.random() * (max - min + 1)) + min)
2
Math.floor((Math.random() * (max - min + 1)) + min)
6
Math.floor((Math.random() * (max - min + 1)) + min)
7
Math.floor((Math.random() * (max - min + 1)) + min)
3
Math.floor((Math.random() * (max - min + 1)) + min)
4
Written by Loek van den Ouweland on 2021-08-16. Questions regarding this artice? You can send them to the address below.