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Date Calculator: Days Between Dates, Workdays and Age

Calculate days, weeks, months, and years between dates. Count workdays excluding weekends and holidays, add or subtract days, and calculate your age.

Date and Day Calculator

Find the difference between two dates, add or subtract time from a date, or calculate an age

Public holiday data could not be loaded; only weekends are excluded.

Years0
Months1
Days0
Total days30
Total weeks4 + 2
Total hours720
Total minutes43,200
Business days22
Weekend days8
Public holidays (weekdays)0
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Date and Day Calculation Guide: Date Differences, Workdays, Age, and Calendar Operations

We need calendar calculations when setting project deadlines, tracking formal contract periods, counting down to military discharge, or finding exactly how much time has passed between two events. But calendar months have 28, 29, 30, or 31 days, a leap year is added every 4 years, and public holidays intervene, so counting days mentally can often be misleading.
HesapYap Date and Day Calculator; instantly finds the exact difference in days and time between two dates, counts workdays excluding weekends and public holidays, adds or subtracts days/months from a date, and provides a detailed age breakdown.

1. How Is the Number of Days Between Two Dates Calculated?

The unit used to express the time between two dates depends on the purpose:
  • Total Days: Uninterrupted calendar days between two dates (for example, 45 days).
  • Weeks and Remaining Days: Found by dividing the total duration by 7 (for example, 6 weeks and 3 days).
  • Years, Months, and Days: Duration expressed using actual calendar month lengths (for example, 1 year, 2 months, 14 days).

Inclusive Versus Exclusive Counting

  • Standard Difference (Exclusive): The time from 1 October to 5 October is
    5−1=4 gu¨ndu¨r5 - 1 = \mathbf{4\text{ gündür}}
    
    .
  • Counting Both Days (Inclusive): When both the start and end dates count as work or event days (for example, attending a fair rather than staying at a hotel), the duration is
    5 takvim gu¨nu¨\mathbf{5\text{ takvim günü}}
    
    in total.

2. What Is a Business Day Calculation?

A business day calculation finds only the days actually worked between two dates.
  • Standard Business Days: Saturdays and Sundays are treated as weekend days and excluded.
  • Public Holidays: Under the Ulusal Bayram ve Genel Tatiller Hakkında Kanun (Law No. 2429 on National and Public Holidays), 1 January, 23 April, 1 May, 19 May, 15 July, 30 August, 29 October, and religious holidays (Ramazan Bayramı, Eid al-Fitr, and Kurban Bayramı, Eid al-Adha) must also be deducted if they fall on weekdays.

Toplam I˙s¸ Gu¨nu¨=Toplam Takvim Gu¨nu¨−(Hafta Sonu Gu¨nleri)−(Hafta I˙c¸i Resmi Tatiller)\text{Toplam İş Günü} = \text{Toplam Takvim Günü} - (\text{Hafta Sonu Günleri}) - (\text{Hafta İçi Resmi Tatiller})



Where Are Business Days Used?

  • Contract and Tender Periods: Clauses such as "delivery within 15 business days" count only working days, rather than calendar days.
  • Shipping and Logistics: Planning periods when deliveries do not take place on weekends and holidays.
  • Banking and Settlement (EFT/FAST/Stock Exchange): Calculating value dates and settlement dates (T+2).

3. Adding/Subtracting Days, Weeks, Months, or Years from a Date

Moving forward or backward from a given date determines the day on which the target date falls.

The "Month-End Overflow" Rule When Adding Months

The most common problem when adding months is that the same day does not exist in the target month:
  • 31 January plus 1 month cannot produce 31 February, so a calendar rule applies.
  • Standard algorithms adjust this date to the last day of February (28 February or, in a leap year, 29 February).

Adding Business Days

When asked to "add 10 business days" to a date, the tool advances the calendar while skipping Saturdays, Sundays, and any public holidays until the next valid business day.

4. The Leap Year Rule and February

The Earth takes approximately 365 days and 6 hours to orbit the Sun. This extra 6 hours adds up to 1 full day (24 hours) every 4 years and is added as the 29th day of February.
Rules for Identifying a Leap Year:
  1. A year divisible by 4 is a leap year (2024, 2028, 2032).
  1. However, century years divisible by 100 are not leap years (1900 and 2100 are common years).
  1. The only exception to this rule: If the century year is also divisible by 400 , it is a leap year (1600 and 2000 are leap years).

5. Age Calculation and Time Counter

Age is the calendar difference between the date of birth and today's date:
  • Completed Age: The number of full years completed (for example, someone aged 25 years and 11 months is legally 25 and is in their 26th year of life).
  • Total Time Lived: A breakdown of total days, hours, minutes, and seconds since birth.
  • Time Until the Next Birthday: A countdown showing how many days and hours remain until your next birthday.

6. Important Note on Legal and Administrative Deadlines (HMK Articles 91-94)

Procedural rules that differ from general calendar rules apply to legal deadlines for filing cases, appeals, enforcement objections, or tax cases:
  1. The First Day Is Not Counted: If the period is specified in days, the day of service is excluded; the period starts on the following day.
  1. A Deadline Falling on a Holiday: If the final day falls on a public holiday or weekend, the period automatically extends until the end of working hours on the first business day following the holiday.
  1. Judicial Recess: Under the Hukuk Muhakemeleri Kanunu (Code of Civil Procedure), deadlines falling between 20 July and 31 August each year are deemed extended by one week from the day after the judicial recess ends.

Frequently Asked Questions

Is the end date counted when calculating days between two dates? The standard time difference calculation measures the interval between the start and end. For example, a process starting on Monday and ending on Tuesday has a difference of 1 day. If you want to include both days as "full days," add +1 to the calculated result.
Is a month always treated as 30 days? No. Although we say "1 month" in everyday language, actual calendar months have 28, 29, 30, or 31 days. Precise calculations use the actual number of days in calendar months.
Which method is used for a countdown to military discharge? Military discharge countdowns generally count the remaining calendar days excluding the discharge date. Your unit's ASAL (Military Recruitment) records should be used for the official discharge date.

Standards and Sources

  • Hukuk Muhakemeleri Kanunu, Law No. 6100 (Articles 91-94, Time Limits): Rules for calculating legal time limits.
  • Ulusal Bayram ve Genel Tatiller Hakkında Kanun, Law No. 2429: Legislation on public holidays.
Information: This content and calculator are intended for general planning. For final assessments of service of process, limitation periods, appeals, or administrative application deadlines, consult a lawyer or the relevant legislation.