Planet Distance Calculator & Travel Time Between Planets | PlanetPath

Planet distance & travel time calculator

Explore the Distance Between Planets

Select a planet to see its approximate distance from Earth in kilometers, miles and astronomical units. Then enter a spacecraft speed and PlanetPath estimates how long the journey would take.

Open Planet Calculator Explore Planets
  • 7 planetsMercury to Neptune
  • km, mi & AUThree distance units
  • Any speedYour travel time
Animated inner solar system Mercury, Venus, Earth, Mars and Jupiter orbit the Sun at their real relative speeds. When the planets line up, a spacecraft launches from Earth and follows a curved transfer path to Mars.
Planets move at their real relative speeds. Sizes and distances are not to scale.

Earth to Mars distance, at a glance

Mars is never the same distance away twice. Switch between its closest, average and farthest positions to see how much the gap changes, and how that reshapes the journey.

  • Distance shown in kilometers, miles and astronomical units
  • Travel time converted into days, months or years
  • Choose any planet and any speed in the full calculator

Earth to Mars

Distance
225 million km 139.8 million mi, 1.50 AU
Spacecraft speed
40,000 km/h 24,855 mph
Estimated travel time
≈ 234 days about 7.7 months

Preview only. Straight-line estimate at constant speed.

Calculate Your Journey

How the planet travel time calculator works

Three inputs, one clear answer. No sign-up and nothing to install.

  1. Select a planet

    Choose any planet from Mercury to Neptune. PlanetPath shows its closest, average and farthest distance from Earth.

  2. Enter spacecraft speed

    Type a speed in km/h or mph. Try a real spacecraft’s speed as a reference, or pick any number you like.

  3. Get estimated travel time

    See how long the trip would take in hours, days and years, calculated as distance divided by speed.

Explore the planets

Each range below is the approximate distance from Earth, from closest approach to farthest point. Open any planet to calculate its travel time.

  • Mercury

    77–222 million km from Earth

    The smallest planet and the closest to the Sun, Mercury completes an orbit every 88 Earth days. With almost no atmosphere, its surface swings from about 430°C by day to −180°C at night.

    Explore Mercury

  • Venus

    38–261 million km from Earth

    Close to Earth in size, Venus is the hottest planet. Its thick carbon dioxide atmosphere holds surface temperatures near 465°C, and it spins so slowly that a day there outlasts its year.

    Explore Venus

  • Mars

    55–401 million km from Earth

    The Red Planet owes its color to iron oxide dust. It is home to Olympus Mons, the tallest known volcano in the solar system, and two small moons, Phobos and Deimos.

    Explore Mars

  • Jupiter

    588–968 million km from Earth

    The largest planet is more than twice as massive as all the others combined. Its Great Red Spot is a storm wider than Earth that has been observed for well over a century.

    Explore Jupiter

  • Saturn

    1.2–1.7 billion km from Earth

    Saturn’s bright rings are made mostly of water ice. The planet is less dense than water and takes about 29.5 Earth years to complete one orbit of the Sun.

    Explore Saturn

  • Uranus

    2.6–3.2 billion km from Earth

    An ice giant tilted about 98° on its axis, Uranus rolls around the Sun on its side. Each pole gets roughly 42 years of continuous sunlight, followed by 42 years of darkness.

    Explore Uranus

  • Neptune

    4.3–4.7 billion km from Earth

    The most distant planet has the fastest winds measured in the solar system, topping 2,000 km/h. In 1846 it became the first planet located by mathematical prediction.

    Explore Neptune

What you can calculate

PlanetPath turns planetary distances into numbers you can compare. Here is what the calculator returns, using the average Earth-to-Mars distance as an example.

Sample result: Earth to Mars Average distance, 40,000 km/h
Planetary distanceClosest to farthest range
55–401 million km
Distance in kilometersPlanet distance in km
225,000,000 km
Distance in milesFor imperial comparisons
139,800,000 mi
Astronomical units1 AU = average Earth–Sun distance
1.50 AU
Spacecraft travel timeHours, days and years
≈ 234 days
Planet factsMoons, year length and more
2 moons, 687-day year

Why use PlanetPath?

Built for students, teachers and anyone curious about space who wants a quick, dependable estimate without digging through orbital data.

  • Simple calculations

    Pick a planet, set a speed, and the result appears instantly.

  • Educational information

    Every planet comes with key facts to put its distance in context.

  • Easy-to-understand results

    Huge numbers are rounded and shown in km, miles, AU and everyday time units.

  • Mobile friendly

    Works smoothly on phones, tablets and desktops, in any modern browser.

  • Free to use

    No account, no paywall and no limit on how many journeys you plan.

Frequently asked questions

Answers about planetary distances and how travel time is estimated.

How far is Mars from Earth?

The distance between Earth and Mars ranges from about 54.6 million km at the closest possible approach to roughly 401 million km when the planets are on opposite sides of the Sun. The average is about 225 million km.

Why does the distance between Earth and other planets keep changing?

Every planet orbits the Sun at its own speed and distance, and the orbits are slightly elliptical. As the planets move, the gap between them grows and shrinks, so distances are usually given as closest, average and farthest values.

How is spacecraft travel time calculated?

PlanetPath divides the distance by the speed you enter: travel time = distance ÷ speed. The result assumes a straight-line path at a constant speed, which makes it a clear educational estimate rather than a mission plan.

Why do real space missions take a different amount of time?

Real spacecraft follow curved transfer orbits and often use gravity assists from other planets. NASA’s Perseverance rover launched in July 2020 and landed on Mars in February 2021, about seven months later. Voyager 2 took 12 years to reach Neptune.

What is an astronomical unit (AU)?

An astronomical unit is the average distance between Earth and the Sun, defined as 149,597,870.7 km (about 93 million miles). It is a convenient scale for comparing distances within the solar system.

What spacecraft speed should I use?

Any speed works. For reference, Voyager 1 travels at roughly 61,000 km/h, and NASA’s Parker Solar Probe has reached about 690,000 km/h near the Sun, the fastest speed of any human-made object.

How long does light take to travel from Earth to Mars?

Light, and radio signals, take between about 3 and 22 minutes to cross the distance between Earth and Mars, depending on where the two planets are in their orbits.

Is PlanetPath free to use?

Yes. The Planet Path Calculator is free, needs no account, and works in any modern browser on phones, tablets and desktops.

Ready to Explore Your Planetary Journey?

Pick a destination, set your speed, and find out how long it would take to get there.

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