Time math
Datetime Difference Calculator
Calculate the precise duration between two dates in years, months, days, and seconds.
Defaults to your current date and time.
Update either value to measure a new gap.
About Date & Time Difference
The Datetime Difference Calculator computes the exact time delta or duration between two specific dates. It provides a granular breakdown of the date gap, showing the total years, months, days, hours, and minutes between the start and end points.
Perform accurate time math for project planning, billing cycles, or uptime analysis. Calculating time intervals manually is prone to errors due to leap years and varying month lengths; this tool handles all calendar logic for you.
Select a Start Date and an End Date. The calculator instantly updates to show the full duration string (e.g., "2 years, 3 months, 4 days") as well as the total count of individual units (e.g., "Total Days: 825").
Under the Hood
Duration calculations are performed using `date-fns` `intervalToDuration` and `differenceIn[Unit]` functions. This accounts for variable month lengths and leap years accurately, avoiding simpler epoch-subtraction errors. The tool breaks down the total duration into component parts (years, months, days, etc.) and also provides total counts (e.g., "Total Days") for versatile use cases.