Start with Mars, then try every planet, real worlds around other stars, and a clock near Sagittarius A*.
Examples & helpTry Mars, another world, or a clock near the black hole at the center of our galaxy.
As of
About Earth years
About Mars years
That is Earth days from your birth date to today. Your lifetime is the same: a longer year gives a smaller number. This does not mean your body ages differently.
For a planet, a year is one trip around its star. We count the calendar days from your birth date to today, then divide by that world’s approximate orbital period. Birth time is not included, and the result is not a count of completed birthdays.
Sagittarius A* is different: it is the roughly four-million-solar-mass black hole at the center of the Milky Way. That result uses the teaching formula local time = far-away time × √(1 − horizon radius ÷ distance). It imagines a clock somehow hovering at a fixed distance outside a non-rotating black hole.
The real Sagittarius A* spins. Motion, spin, the journey, radiation and the enormous force needed to hover are omitted. The number is a gravity thought experiment, not a safe orbit, survival estimate or travel plan.
Sources: NASA planetary fact sheet, TRAPPIST-1 e, Kepler-186f, 55 Cancri e, NASA black-hole time-dilation math, and NASA: black holes. Sources reviewed .
A planetary year is one orbit around a star. Your age in Mars years is smaller because a Mars year lasts about 687 Earth days. This changes the unit used to count your lifetime; it does not mean a trip to Mars makes you biologically younger.
The examples use fixed reference dates to explain the math. The live space-age calculator uses today on your device, so its result changes over time.
That is about 1.9 Earth years using the tool’s 365.25-day average year. The two numbers describe the same lifetime in different orbital-year units.
A Jupiter year is approximately 4,331 Earth days in this model. You still reached your twentieth Earth birthday; Jupiter simply completes fewer orbits during that time.
No. A year measures an orbit; a day measures a rotation. This calculator compares orbital years. Visit Time in space to learn about Mars sols, lunar time and the International Space Station’s UTC clock.
No. That option illustrates gravitational time dilation with a simplified stationary-clock model outside a non-rotating black hole. It is a teaching example, not a travel, survival or biological-aging prediction for the real Sagittarius A*.
The tool uses rounded orbital periods, counts calendar dates rather than a precise birth instant, and rounds displayed ages. The Earth-year comparison uses an average of 365.25 days rather than completed birthdays.
Further reading: NASA: Mars orbit and time facts