What counts as a business day?

A business day is a weekday (Monday through Friday) that is not a public holiday. Our calculators allow you to exclude weekends and a list of common public holidays for accurate business day calculations.

How is age calculated?

Age is calculated as the complete duration from the date of birth to the current date, expressed in years, months, and days. We account for leap years to ensure the highest accuracy.

Yes. All calculations happen directly in your browser. We do not store any personal information you enter into the calculators. Your data never leaves your device.

Can I use these tools on my mobile device?

Absolutely! DateKeep is designed to be fully responsive, which means it works seamlessly on desktops, tablets, and smartphones. All features are available on any device.

How accurate are the time and date calculations?

Our calculators use a reliable and widely-used date-fns library for all calculations. This ensures high accuracy, including accounting for complexities like leap years. For time-sensitive operations like the countdown timer, accuracy depends on your device's clock.

What is a Unix Timestamp?

A Unix timestamp represents a point in time. It is the number of seconds that have elapsed since midnight UTC on January 1, 1970. It's a common standard used in computing.

What is a Julian Date?

A Julian Date or Julian Day Number (JDN) is the continuous count of days since the beginning of the Julian period (January 1, 4713 BC). It is used primarily in astronomy to provide a single, unambiguous system for dating events without confusion over different calendar systems or time zones.

Julian Date Converter | DateKeep

About the Julian Date Converter

The Julian Date Converter is a specialized tool for scientists, astronomers, historians, and anyone needing to work with an unambiguous dating system. It provides a simple way to convert between the familiar Gregorian calendar and the Julian Day Number (JDN), a system that counts days continuously from a fixed point in the distant past.

Why Use Julian Dates?

Calculating the time between two dates in the Gregorian calendar can be complex due to months of different lengths, leap years, and calendar reforms. The Julian Day system simplifies this by representing any date and time as a single number. This makes it incredibly useful for astronomical calculations, where precise time differences between observations are critical. It eliminates any confusion related to time zones, daylight saving, or calendar irregularities.

Features

Two-Way Conversion: Convert from Gregorian to Julian or from Julian back to Gregorian.
Instant Calculation: The conversion happens automatically as you type.
High Precision: The Julian Day Number includes a fractional part to represent the time of day.
Simple Interface: A clean and straightforward design makes converting dates quick and easy.

Related Tools

If you work with computer time, you may also find the Unix Timestamp Converter useful. For converting between different cultural calendar systems, try the World Calendar Converter.