Create a random number between -100 and 100 in JavaScript?

javascript random range negative-number

36,012

First, generate a random number between 1 - 200 then subtract 100:

var randomNumber = Math.floor(Math.random() * 201) - 100;

36,012

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Updated on July 09, 2022

Cool Guy Yo almost 2 years

Possible Duplicate:
Generating random numbers in Javascript

I have the following code var randomnumber=Math.floor(Math.random()*101); that generates a random number for me between 1 and 100. What I would like to do is generate a random number between -100 and 100. I am not sure what to do exactly. Any help would be appreciated.
- Lightness Races in Orbit about 12 years
  
  You could start by reading your Javascript function reference.
Ben about 12 years

+1 was just writing the same answer..
Ben about 12 years

Shouldn't it be 201 to include 100?
XDS over 5 years

Quick question: Can Math.floor() return a value that falls inside [0.99999999999999995, 0.99999999999999999]. Because if it can then the result will be 101 which is outside the given bounds (at least that's what I surmised by running tests on the chrome console). Of course it's a small chance for such a corner case to actually take place (near hardware error). But still its eerie.
XDS over 5 years

How about "a + Math.floor(Math.random() * (b – a))" <- this seems more concise.