DateKeep

The definitive date and time utility

Articles & Guides

The Date of Easter: The Complex Science of the Ecclesiastical Calendar

November 6, 2025

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Time Since Epoch: Unix, Java, and Why 1970 is the Digital Zero

November 5, 2025

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Ordinal Dates Explained: The Day-of-Year System (DDD)

November 4, 2025

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Time Zone Arithmetic: Solving Day-Crossing and Date Line Calculations

November 3, 2025

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Solar Hijri Calendar: The Science of the Persian Year (vs. Gregorian)

November 2, 2025

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Mastering Date Math: Simple Rules for Adding and Subtracting Time

November 1, 2025

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The Sabbatical and Jubilee Cycles: Time in Ancient Law

October 31, 2025

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The Earth's Time: Solstices, Equinoxes, and the Changing Seasons

October 30, 2025

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Coordinated Universal Time (UTC): The Definitive Time Standard Explained

October 29, 2025

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Why Seven Days? The History and Origin of the Week

October 28, 2025

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Date Incrementer: Advanced Forecasting by Adding Complex Time Intervals

October 27, 2025

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Tracking the Decades: A Statistical Look at the Century

October 26, 2025

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The Day the Calendar Changed: The History of the 1752 Gregorian Switch

October 25, 2025

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The Hijri Calendar: A World-Class Reference on the Islamic Lunar System

October 24, 2025

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The Hebrew Calendar: A Masterpiece of Luni-Solar Calculation

October 24, 2025

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A Timeline of Time: The History of the Calendar from Caesar to Today

October 23, 2025

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Time Management Mastery: Using Your Timer for Ultimate Focus

October 22, 2025

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The Ultimate Year Planner: Facts and Figures for Any Calendar Year

October 21, 2025

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The Time Drift: Why Your Clock Isn't As Accurate As You Think

October 20, 2025

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Date & Time in Programming: A Guide for Developers and Data Scientists

October 19, 2025

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The Mathematics of Time: How Calendars Handle the Earth's Orbit

October 18, 2025

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Converting Julian Dates in Excel (Functional SEO)

October 17, 2025

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Julian Day Number (JDN): The Astronomer's Time Standard

October 16, 2025

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Julian Date vs. Julian Calendar: Clarifying the Confusion

October 15, 2025

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The Ultimate Date Calculator and Time Utility Hub

October 14, 2025

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The Complete Time Calculator & Converter Resource

October 14, 2025

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Free Online Stopwatch and Timer: Your Tool for Precision Timing

October 13, 2025

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Your Global Holiday Calendar: Plan for US Federal & Cultural Dates

October 13, 2025

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Time Difference: Calculate Elapsed Time Down to the Second

October 12, 2025

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What Day Was It? The Ultimate Weekday Calculator

October 12, 2025

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Date Format Converter: Ensuring Compatibility Across Systems

October 11, 2025

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Is This a Leap Year? The Three Essential Rules Explained

October 11, 2025

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Your Free Online Countdown Timer & Clock

October 10, 2025

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What is a Julian Date? (JDN)

October 10, 2025

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How to Accurately Set Project Deadlines

October 9, 2025

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A Guide to World Calendars

October 9, 2025

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How Many Days Are Between Two Dates?

October 8, 2025

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How Old Am I? Calculate Your Exact Age

October 8, 2025

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What is a Unix Timestamp? Epoch Time Explained

October 7, 2025

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Mastering Time Zones and Daylight Saving Time

October 7, 2025

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