JavaScript - get difference between two dates in days

Warning:

Don't use 5/10/2022 or 10/10/2022 formats to create Date objects, it's non-standard and it's up to the browser how they are parsed.

You should:

1. use subtraction to get the difference between two dates in milliseconds,
2. then divide the difference by number of milliseconds in 1 day (1000 * 60 * 60 * 24)
3. then round it using one of the following methods: Math.ceil(), Math.round() or Math.floor().

Practical example

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const date1 = new Date('2022-10-20T00:00:00.000Z');  // or just:  2022-10-20

const date2 = new Date('2022-10-25T01:00:00.000Z');  // or just:  2022-10-25

​

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const milliseconds = date2 - date1;                            // difference in milliseconds

const days = Math.ceil(milliseconds / (1000 * 60 * 60 * 24));  // difference in days

​

console.log(days);  // 6

Hint: consider to round days using Math.ceil(), Math.floor() or Math.round() methods if needed.

See also

1. JavaScript - calculate days difference between two dates

2. ISO 8601 - Z meaning in yyyy-MM-ddTHH:mm:ssZ date time format

References

1. Math.round() - JavaScript | MDN
2. Math.ceil() - JavaScript | MDN
3. Math.floor() - JavaScript | MDN
4. Math.abs() - JavaScript | MDN