The Date Add Calculator performs date arithmetic by adding or subtracting time units (years, months, days, or weeks) from a given start date. It’s useful for calculating future or past dates based on a specific duration.
The calculator works by:
Taking a valid start date in YYYY-MM-DD format
Applying the specified operation (add/subtract) with the given value and time unit
Returning the resulting date in YYYY-MM-DD format
The calculation handles:
Month/year rollovers automatically
Different month lengths
How to Use
Call the function with these parameters:
$start: Initial date (e.g., “2023-05-15”)
$value: Number of units to add/subtract (e.g., “3”)
$unit: Time unit (“year”, “month”, “day”, or “week”)
$type: Operation type (“add” or “subtract”)
Practical Applications：
Calculating project deadlines
Determining expiration dates
Scheduling future events
Finding past dates for historical analysis
English