# Get the Sum of an Array of Numbers in JavaScript Last updated: Jul 25, 2022

## Get the Sum of an Array of Numbers#

To get the sum of an array of numbers:

1. Use the `Array.reduce()` method to iterate over the array.
2. Set the initial value in the `reduce` method to `0`.
3. On each iteration, return the sum of the accumulated value and the current number.
index.js
```Copied!```const arr = [5, 15, 45];

const sum = arr.reduce((accumulator, value) => {
return accumulator + value;
}, 0);

console.log(sum); // 👉️ 65
``````

The `accumulator` parameter is initially set to `0` because that's what we passed as the second argument to the reduce method.

On each iteration, we return the sum of the `accumulator` and the current array element.

An alternative and perhaps simpler approach is to use a `for...of` loop.

To get the sum of an array of numbers:

1. Declare a `sum` variable and initialize it to `0`.
2. Use the `for...of` loop to iterate over the array.
3. On each iteration, reassign the `sum` variable to its current value plus the value of the current element.
index.js
```Copied!```const arr = [5, 15, 45];

let sum = 0;

for (const value of arr) {
sum += value;
}

console.log(sum); // 👉️ 65
``````

The for...of loop allows us to iterate over an array.

Notice that we declared the `sum` variable using the `let` keyword. Had we declared the variable using `const`, we wouldn't be able to reassign it.

On each iteration, we reassign the `sum` variable to its current value plus the value of the current element.

You can also use a basic `for` loop to sum an array of numbers.

index.js
```Copied!```const arr = [5, 15, 45];

let sum = 0;

for (let index = 0; index < arr.length; index++) {
sum += arr[index];
}

console.log(sum); // 👉️ 65
``````

This example achieves the same goal, but instead of using `for...of` we used a basic `for` loop.

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