How do you calculate the number of days between two dates?

Calculating the days between two dates means finding the total span of time that separates them on the calendar. This is done by converting both dates into a common reference point (such as milliseconds since a fixed epoch) and finding the difference. The result can then be expressed in several ways - as a simple day count, a calendar breakdown of years, months, and days, or converted into other units like weeks, hours, minutes, and seconds.

Date math gets tricky quickly because months have different lengths, years can be leap years, and time zones or specific times of day can shift the result by a day. Manually counting days on a calendar is error-prone, especially across multiple months or years, which is why a dedicated calculator is useful for planning events, tracking deadlines, or measuring milestones.

Tool description

This days between dates calculator finds the exact time elapsed between a start date and an end date. Enter both dates and the tool instantly displays the total number of days along with a full calendar breakdown (years, months, and days) and totals in other units (weeks, hours, minutes, and seconds). Optional settings let you include a specific time of day for more precise results or count the end date itself in the total.

Features

  • Calculates the exact duration between any two dates, with an optional calendar breakdown of years, months, and days
  • Converts the total into weeks, hours, minutes, and seconds
  • Supports specific times of day and an option to include the end date in the total