Use this page to generate a random number in any range of numbers that you desire. You can even get random numbers with decimal point included. I'm sure that this is one of the best random number generators out there. Well, actually, maybe not, I guess.
Generate another random number, between
and
.
Include numbers after the decimal point.
var randomnumber = Math.floor(Math.random() * (maximum - minimum + 1)) + minimum;
Why use Math.floor() and not Math.round()? Well, as an example, let's say that you want to generate numbers in the range of 0 to 2. If you do Math.round(0.4) you get 0, and if you do Math.round(0.5) you get 1. On the other end of your random range, if you do Math.round(1.4) you get 1, and if you do Math.round(1.5) you get 2.
But this means that you are half as likely of getting 0 and 2 as you
are of getting 1. Look at this number line:
| 0 | 1 | 2 | 0.0-0.1-0.2-0.3-0.4-0.5-0.6-0.7-0.8-0.9-1.0-1.1-1.2-1.3-1.4-1.5-1.6-1.7-1.8-1.9-2.0
See how the space for 0 and 2 is smaller than the space for 1? If you wanted to have an equal chance of getting 0, 1, and 2, you would have to do some crazy stuff with decimal numbers in your random number formula.
Using Math.floor() makes it unnecessary to do the crazy decimal
number stuff that you would have to do if you wanted to use Math.round(). This is how the number line is when using Math.floor():
| 0 | 1 | 2 | 0.0-0.1-0.2-0.3-0.4-0.5-0.6-0.7-0.8-0.9-1.0-1.1-1.2-1.3-1.4-1.5-1.6-1.7-1.8-1.9-2.0-2.1-2.2-2.3-2.4-2.5-2.6-2.7-2.8-2.9
As you can see, each of the three numbers in the 0 to 2 range have the same amount of space on this number line, making each one equally likely to result from using Math.floor().