Convert day lengths between Earth and other planets. Based on rotational periods. Runs in your browser.
Planetary day conversion is the process of converting day counts between different planets in our solar system. Each planet has a unique rotation period (the time it takes to complete one full rotation on its axis), which determines the length of a day on that planet. A planetary day converter allows you to convert a specific number of days on one planet to the equivalent number of days on another planet.
For example, if you want to convert 10 Jupiter days to Earth days, you would use a planet day converter. Since a day on Jupiter is only 0.41 Earth days (approximately 9.9 hours), 10 Jupiter days equals approximately 4.1 Earth days. Converting Jupiter days to Earth days is a common use case for this planetary day converter. This is different from age calculation, which uses orbital periods (year length) rather than rotation periods (day length). Want to calculate your age on other planets? See our Age on Other Planets calculator.
Planetary day conversion is useful for understanding relative time scales across planets, educational purposes, and scientific calculations. Whether you're converting Jupiter days to Earth days, Saturn days to Earth days, or any other planetary day conversion, our planet day converter provides accurate results based on precise astronomical data. This tool makes it easy to convert days between any two planets in our solar system.
A planetary day is defined as the time it takes for a planet to complete one full rotation on its axis. This is measured relative to the Sun (solar day) or relative to the stars (sidereal day). Our planetary day converter uses solar day lengths, which is the standard measurement for day length.
Each planet's day length varies dramatically due to differences in rotation speed. For example:
To convert days between planets, the converter multiplies the number of days on the source planet by the ratio of day lengths. For example, to convert Jupiter days to Earth days, multiply by 0.41 (since 1 Jupiter day = 0.41 Earth days). Our planet day converter handles all these calculations automatically.
Question: How many Earth days equal 10 Jupiter days?
Calculation: 10 Jupiter days × 0.41 (conversion factor) = 4.1 Earth days
Result: 10 Jupiter days = 4.1 Earth days. This means 10 full rotations of Jupiter equal approximately 4.1 full rotations of Earth.
Question: How many Earth days equal 5 Saturn days?
Calculation: 5 Saturn days × 0.45 (conversion factor) = 2.25 Earth days
Result: 5 Saturn days = 2.25 Earth days. Since Saturn rotates faster than Earth, fewer Saturn days are needed to equal Earth days.
Question: How many Earth days equal 7 Mars days?
Calculation: 7 Mars days × 1.026 (conversion factor) = 7.18 Earth days
Result: 7 Mars days = 7.18 Earth days. Mars days are slightly longer than Earth days, so 7 Mars days is slightly more than 7 Earth days.
Explore these related free tools to enhance your productivity and workflow.
Enter the number of Jupiter days you want to convert, select 'Jupiter' as the source planet and 'Earth' as the target planet. The calculator automatically converts using the conversion factor: 1 Jupiter day = 0.41 Earth days. For example, 10 Jupiter days = 4.1 Earth days.
Planetary day conversion converts day counts between planets (e.g., '10 Jupiter days = X Earth days'). Age calculation determines how old you'd be on other planets based on your birth date. Day conversion uses rotation periods (day length), while age calculation uses orbital periods (year length).
A day on Mercury is 58.6 Earth days, Venus is 243 Earth days (retrograde), Earth is 1 day (24 hours), Mars is 1.026 days (~24.6 hours), Jupiter is 0.41 days (~9.9 hours), Saturn is 0.45 days (~10.7 hours), Uranus is 0.72 days (~17.2 hours), Neptune is 0.67 days (~16.1 hours), and Pluto is 6.39 Earth days.
Yes! The calculator supports bidirectional conversion between all planets in our solar system. Simply select your source planet and target planet, enter the number of days, and the calculator shows the converted value instantly.
A planetary day is the time it takes for a planet to complete one full rotation on its axis. This is different from a planetary year (orbital period). For example, a day on Jupiter is only 9.9 hours, but a year on Jupiter is 12 Earth years.
Yes! The planetary day converter is 100% free with no registration required, no usage limits, and no hidden fees. You can convert days between planets as many times as you need.