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Date Calculator Your smart Date Calculator

Simple date calculations for every use case. Fast, accurate, and completely free.

  • Calculate days, weeks, months & years
  • Consider working & business days
  • Find duration between two dates
  • Easy to use – no registration required

Calculate Date

Select a calculation type and enter your values.

Key Facts at a Glance

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Calculation types for adding, subtracting and differences
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German states with all public holidays covered
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Free and without registration – use directly in your browser
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None
Data transfer – all calculations run locally in your browser (GDPR compliant)

The Date Calculator is a free online tool for precise calendar calculations. Easily calculate target dates by adding or subtracting days, weeks, months, and years. The calculator dynamically accounts for the Gregorian calendar, leap years, and German public holidays at the state level. It is ideal as a notice period calculator for contracts, a business day calculator for projects, and a time span tool for personal planning.

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How the Date Calculator Works

The Date Calculator computes a target date in 3 simple steps. Select a start date, enter the desired number of days, weeks, months, or years, and get your result instantly.

1
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Select Start Date

Enter the starting date. Today's date is preselected. The calculator accepts all dates in the Gregorian calendar.

2
⚙️

Enter Time Period

Select plus or minus, and enter the number of years, months, weeks, or days.

3

Get the Result

The Date Calculator shows the computed target date, weekday, calendar week, and workday statistics instantly.

Two Calculation Methods for Precise Results

The Date Calculator offers 2 methods: Add/Subtract Date and Calculate Date Difference. Toggle between them below.

Add or Subtract Date

Enter a start date and choose plus or minus. The calculator adds or subtracts the specified number of days, weeks, months, or years and displays the target date with the weekday and calendar week. Leap years and different month lengths (28, 29, 30, 31 days) are automatically handled.

  • Combine days, weeks, months, and years
  • Fully automatic leap year calculation
  • Based on the Gregorian calendar
Start Date 15.01.2025 + 90 Days Target Date 15.04.2025 Tuesday · CW 16

Calculate Date Difference

Enter 2 dates (start date and end date) and the calculator computes the difference in days, weeks, months, and years. The workday calculator displays the number of workdays, weekend days, and public holidays separately.

  • Date difference in days, weeks, and months
  • Workdays and weekends separated
  • German holidays by state
Start Date 01.03.2025 End Date 15.06.2025 Result 106 Days 15 weeks, 1 day 74 workdays · 32 weekends

A Practical Example

Calculation: "Which date lies 90 days after January 15, 2025?"

Start
15.01.2025 Wednesday
+90
90 Days ≈ 12 weeks, 6 days
Target
15.04.2025 Tuesday · CW 16
90
Calendar Days
64
Workdays
26
Weekend Days
12
Weeks + 6 Days

Other Applications of the Date Calculator

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Project Planning & Deadlines

Calculate milestones and end dates for projects. The workday calculator counts business days and excludes weekends and holidays.

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Calculate Contract Terms

Determine notice periods, contract renewals, and durations. Calculate precise end dates accounting for public holidays.

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Vacation Planning

Plan your annual leave efficiently. Find bridge days and optimize your time off around national holidays.

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Payment Terms & Invoices

Determine the due date for invoices with terms like "30 days net" or "90 days". The calculator finds the exact date.

🎂

Age Calculator & Birthdays

Calculate exact age in years, months, and days. Simply enter the birth date as the start date.

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Development & Integration

Use date calculations as a reference for Excel, Google Sheets, Python datetime, or the JavaScript Date API.

📚 Sources & References

  • Gregorian Calendar: International standard for calendar date calculations since 1582
  • ISO 8601: International standard for date and time formats (calendar week, week numbers)
  • Holiday Laws: State regulations and public holiday calculations

🔄 Last Updated

Recent updates to the Date Calculator

13.07.2025 New FAQ section with frequently asked questions about the calculator
13.07.2025 Interactive help guide with explanations for all input fields
13.07.2025 Added specialized calendar calculation guide sections

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Frequently Asked Questions (FAQ)

Find quick answers to the most important questions about date calculations and deadlines.

Workdays are calculated by excluding Saturdays and Sundays. If 'Exclude public holidays' is enabled, the tool also detects all official public holidays for the selected German state during that period and subtracts them.

The tool considers all statutory public holidays in Germany. Depending on the selected state, this includes regional holidays such as Corpus Christi, All Saints' Day, Reformation Day, or Epiphany. National holidays like New Year's Day, Good Friday, Easter Monday, Ascension, Whit Monday, Labour Day, Day of German Unity, and Christmas are always included.

Yes, our date calculator automatically accounts for leap years (years with 366 days and a February 29th) for all past, present, and future calculations. You don't need to make any manual adjustments.

According to § 187 BGB, a deadline usually begins on the day after the event. If a deadline ends on a Saturday, Sunday, or public holiday, the deadline is extended to the next working day (§ 193 BGB). Our tool helps you compute these rules accurately.