Future & Past Date Calculator
Add or subtract days, weeks, months, and business days to project exact calendar dates and deadlines.
A future and past date calculator projects calendar dates by adding or subtracting specific durations (days, business days, weeks, months, or years) from any reference date, accounting for leap years and variable month lengths.
Evaluated in hierarchical order (Years -> Months -> Days) to maintain accurate calendar month-end boundaries.
Use units like: y (years), m (months), w (weeks), d (days), b (business days).
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How to Use Future & Past Date Calculator
Select Base Date
Choose your starting date or leave as Today.
Choose Operation (Add or Subtract)
Select whether you want to project into the future or calculate backwards into the past.
Input Interval Units
Specify the exact count of days, business days, weeks, months, or years to project the target date.
Practical Examples & Conversions
Start Date: Today + 90 Days
Calculates exact target calendar date and weekday
Frequently Asked Questions (PAA)
Related Tools & Converters
Authoritative Standards & Citations
Calculations and algorithms on this page are implemented and verified in strict accordance with the following official technical specifications:
RFC 7519: JSON Web Token (JWT)
Standardized compact, URL-safe means of representing claims to be transferred between two parties.
Web Cryptography API Specification
Standard JavaScript API for performing basic cryptographic operations in web applications.
RFC 4122: A Universally Unique IDentifier (UUID) URN Namespace
Definition of uniform format and generation algorithms for UUIDs.