How many Earth days is 1 Jupiter day?
About 0.414 Earth days—roughly 9.9 hours. Jupiter’s equatorial region completes one rotation in under ten hours, so one Jovian day is much shorter than an Earth day.
Compare rotation lengths (Mars sols, Jupiter’s fast spin, Venus’s slow day)—convert any day count between two planets with clear ratios and a visual chart. All in your browser.
A planetary day converter turns rotation lengths (Mars sols, Jupiter’s ~10-hour spin, Venus’s slow day) into equivalent day counts on another world—using NASA-style sidereal periods in Earth days, calculated locally in your browser.
A planetary day converter compares how long one rotation lasts on each planet versus Earth—not how long a year (orbit) takes. It uses published rotation periods: Earth is 1.000 mean solar day (24 h), Mars uses the mean solar sol (~1.026 Earth days), and other worlds use sidereal rotation lengths expressed in Earth days.
Jupiter’s day is under ten Earth hours; Venus’s sidereal day is about 243 Earth days and spins retrograde. The tool multiplies your entered day count by the ratio of source rotation length to target rotation length.
This is distinct from Age on Other Planets (orbital years) and from the Planetary Year Converter (year-length handoffs). All math runs in your browser; inputs are not uploaded.
Rotation (days/sols) ≠ orbit (years)—use this tool for Mars sol schedules and fast-spinning gas giants, not birthday-by-orbit math.
Concise answers for common searches — definitions, steps, and comparisons.
About 0.414 Earth days—roughly 9.9 hours. Jupiter’s equatorial region completes one rotation in under ten hours, so one Jovian day is much shorter than an Earth day.
One Mars sol (mean solar day) is about 1.026 Earth days (~24 hours 37 minutes). Ten sols span about 10.26 Earth days.
A sidereal day is one spin relative to distant stars (~23 h 56 m on Earth). A solar day is noon-to-noon relative to the Sun (24 h on Earth). Mars uses its mean solar sol; Earth is 1.000 solar day in this tool.
Rotation periods follow NASA planetary fact sheet style values. Earth = 1 mean solar day; Mars = mean solar sol; other bodies use sidereal rotation in Earth-day units.
Formula
Target days = Source days × (source rotation ÷ target rotation)Pick the world you are counting days on and the planet you want to convert into (e.g. Mars → Earth for sols).
Type a non-negative number (decimals allowed). Results and the all-planets grid update as you type.
The result card shows converted days and how many target days equal one source day.
Copy the one-line result, use Share on mobile, or tap a planet in the grid to set it as the target.
Input
10 Mars days → EarthOutput
≈ 10.26 Earth daysBecause each sol is slightly longer than 24 h, multi-sol counts drift relative to Earth clocks.
Common real-world scenarios where this tool saves time.
Convert rover sol logs to Earth days for press releases and shift planning when the ~1.026 ratio accumulates.
Contrast rotation (this tool) with orbital years (Planetary Year Converter) and heliocentric age (Age on Other Planets).
Translate “five local days on Jupiter” into Earth-hour equivalents without hand-calculating 0.414× factors.
Pair with Sunrise/Sunset on Other Planets when a lesson needs both rotation length and approximate daylight duration.
Step-by-step chains that connect related tools for common tasks.
Rotation length is not orbital period.
| Question | This tool | Planetary Year Converter |
|---|---|---|
| Measures | Rotation (local day / sol) | Orbit around the Sun (year) |
| Mars example | 1 sol ≈ 1.026 Earth days | 1 Mars year ≈ 687 Earth days |
| Best for | Sols, Jupiter-hour days, Venus slow spin | Birthday-style year counts |
Use Age on Other Planets when starting from a birth date and orbital periods.
Order-of-magnitude rotation lengths—see the live table on the tool for exact ratios.
| Planet | Earth days per local day | Notes |
|---|---|---|
| Jupiter | ~0.41 | ~9.9 h |
| Saturn | ~0.44 | ~10.7 h |
| Earth | 1.000 | Mean solar day |
| Mars | ~1.026 | Mean solar sol |
| Mercury | ~58.6 | Slow spin |
| Venus | ~243 | Retrograde; longer than its year |
Use the Planetary Year Converter for orbits around the Sun; this tool is for rotation (sols and local days).
Venus rotates very slowly (~243 Earth days per rotation) and retrograde—check the comparison chart first.
Likely cause: Catalogs round mean solar day lengths differently.
Fix: Compare using the same NASA fact sheet epoch; this tool uses the mean solar sol.
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About 0.414 Earth days — roughly 9.9 hours. Jupiter’s equatorial region spins once in a bit under ten hours, so one local “day” is much shorter than Earth’s. Use Jupiter → Earth above with “1” to match this tool’s exact ratio.
One Mars sol (mean solar day) is about 1.026 Earth days (~24 hours 37 minutes). Rover teams track “sols” because the small offset from 24 h adds up over multi-week missions.
Mars rotates once every ~1.026 Earth days. Ten Mars sols span about 10.26 Earth days, which is why mission schedules drift relative to Earth clocks unless teams adjust shifts.
About 243 Earth days for one rotation (sidereal day). Venus spins very slowly and backward (retrograde) relative to most planets — one Venus “day” is longer than a Venus year.
Roughly 0.67 Earth days — about 16.1 hours. Neptune rotates faster than Earth, though not as fast as Jupiter or Saturn.
A sidereal day is one spin relative to the distant stars (~23 h 56 m on Earth). A solar day is noon-to-noon relative to the Sun (24 h on Earth). This converter uses standard published rotation lengths; Mars uses its mean solar day (sol). For Earth we treat 1.000 as the familiar 24-hour day so comparisons stay intuitive.
Most planets spin counterclockwise when viewed from above the north pole. Venus and Uranus are exceptions: their rotations are retrograde (clockwise in that same view). Retrograde affects direction, not how we convert day counts — we still compare lengths in Earth days.
Yes. Set “From” to Earth, “To” to Mars, and enter Earth days. The tool divides by the Mars/Earth day ratio (~1.026), because one Mars sol is slightly longer than one Earth day.
Yes. Choose any source and target, enter a day count, and use Swap to reverse direction. All pairs use the ratio of rotation lengths in Earth days.
No. This tool compares rotation (how fast a planet spins). “Age on other planets” uses orbital periods — how long a year is. Use this page for sols and local days; use Age on Other Planets for birthday-style orbit math.
No. Conversions run entirely in your browser; nothing you type is uploaded.
Day counts and planet selections are converted in your browser. EverydayTools does not upload your inputs to servers.
Rotation values align with NASA NSSDCA planetary fact sheet references. Mars uses mean solar day (sol); other worlds use sidereal periods in Earth-day units.
Educational astronomy only—not for spacecraft clock sync or navigation.
Part of Date & Time Tools
More free tools for the same workflow.
Convert Earth years to orbital years for all planets. A Mars year is 1.88 Earth years; a Neptune year is 165 Earth years. Browser-based, no signup, uses NASA IAU orbital data.
How long does daylight last on Mars, Venus, or Jupiter? Explore sunrise and sunset times based on each planet's rotation period and axial tilt. Browser-based, no signup.
How much would you weigh on Mars (38% of Earth), Jupiter (2.5×), or the Moon (16.5%)? Free weight on other planets calculator using NASA surface gravity values. No signup.
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Reviewed by EverydayTools Editorial Team on 2026-05-21.
Mars sol to Earth days, Jupiter day length, and more—tap a card or use the converter for any day count.
Convert Mars sols, Jupiter days, or any rotation count between two worlds. Shareable link updates as you type.
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Tip: Swap planets to convert in reverse instantly.
Rotation periods are from the NASA planetary fact sheet (sidereal, except Mars sol). Earth = 1 is one mean solar day.