How to Generate a Random Number from 1 to 100 in JavaScript? (With Examples)

Generating random numbers is one of the most common tasks in JavaScript—whether you are building games, quizzes, OTP systems, or randomized features.

In this post, you’ll learn exactly how to generate a random number between 1 and 100 using JavaScript, with examples and outputs.

🎯 The Simple Answer

JavaScript provides the built-in function:

Math.random()

This returns a random decimal between 0 (inclusive) and 1 (exclusive):

0.00023
0.89233
0.55555

To convert it into a number from 1 to 100, use:

Math.floor(Math.random() * 100) + 1;

✅ Example: Get a Random Number from 1 to 100

const randomNum = Math.floor(Math.random() * 100) + 1;
console.log(randomNum);

Sample Output

73

(Your number will be different every time.)

🔍 How It Works? (Step-by-Step)

1. Math.random()

Generates random values like:

0.12
0.98
0.45

2. Multiply by 100

0.45 * 100 = 45
0.98 * 100 = 98

3. Math.floor()

Removes decimals (round down):

45.67 → 45
98.12 → 98

4. Add +1

Because random numbers could be 0, we add 1 to shift the range from:

0–99  →  1–100

🔁 Generate and Print 10 Random Numbers (1–100)

for (let i = 0; i < 10; i++) {
  console.log(Math.floor(Math.random() * 100) + 1);
}

Sample Output

18
77
9
42
100
13
65
2
88
50

✨ Bonus: Function to Easily Reuse Anywhere

function randomFrom1To100() {
  return Math.floor(Math.random() * 100) + 1;
}

console.log(randomFrom1To100());

🎮 Practical Uses

You can use this method in:

✔ Games

Random enemies, damage points, levels.

✔ Quiz Apps

Random questions, random rewards.

✔ OTP / Token Generators

Random 2-digit numbers.

✔ Simulations

Random probability calculations.

🚀 Conclusion

To generate a random number between 1 and 100 in JavaScript, use:

Math.floor(Math.random() * 100) + 1;

It is simple, accurate, and used widely in real-world applications.