Question

How to add N weeks to the current date in Swift

Answer 1

import Foundation

/**
 * Adds a specified number of weeks to the current system date.
 *
 * - Parameter weeks: The number of weeks to add (supports negative numbers to subtract).
 * - Returns: A new `Date` representing the future date, or `nil` if the 
              calculation overflows or fails.
 */
func addWeeksToCurrentDate(weeks: Int) -> Date? {
    // 1. Get the current date and time
    let currentDate = Date()
    
    // 2. Use the current calendar to add the specified weeks.
    // .weekOfYear cleanly handles calendar-based week increments.
    return Calendar.current.date(byAdding: .weekOfYear, value: weeks, to: currentDate)
}

// ==========================================
// Example Usage:
// ==========================================

let weeksToAdd = 4

if let futureDate = addWeeksToCurrentDate(weeks: weeksToAdd) {
    // 3. Format the resulting date into standard YYYY-MM-DD format
    let formatter = DateFormatter()
    formatter.dateFormat = "yyyy-MM-dd"
    
    let todayString = formatter.string(from: Date())
    let futureString = formatter.string(from: futureDate)
    
    print("Today: \(todayString)")
    print("After adding \(weeksToAdd) weeks: \(futureString)")
} else {
    print("Could not calculate the future date.")
}


/*
run:

Today: 2026-11-08
After adding 4 weeks: 2026-12-06

*/

 

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