⏱️ Fall Time from Any Height on Every Planet

Drop an object from 100 metres and it hits the ground in 4.5 seconds on Earth. Do the same on the Moon and it takes 11.1 seconds — more than twice as long, at less than half the speed. On Jupiter it is over in 2.8 seconds at 253 km/h. Gravity is the only variable, and the formula is one of the oldest in physics: t = √(2h / g).

This calculator answers the question behind every sci-fi fall, every video-game death drop and every "what if I jumped off this building on Mars" thought experiment. Enter any height from a metre to ten kilometres, and it returns the fall time and impact speed for 14 bodies: the Sun, eight planets, the Moon, Pluto, Ceres, Titan and Europa. Ceres takes longest because its gravity is only 2.8% of Earth’s; the Sun is fastest at 27.9 g, where a 100 m fall lasts just 0.85 seconds.

The impact speed is the derived metric that matters for survival — it is what actually hurts. The same 100 m fall ends at 159 km/h on Earth but only 65 km/h on the Moon, which is why Apollo astronauts could hop and land safely in ways that would be fatal at home. If you enjoy comparing bodies across the solar system, also see how far blood would spray under the same gravity, how far a sneeze travels on the Moon, or how many balloons you need to float on each planet. And for a gentler gravity question, check how tall you would grow on other worlds.

In vacuum, a falling object accelerates at the local surface gravity g. The equations are:

1. Fall time — t = √(2h / g), derived from h = ½gt². Time scales as the inverse square root of gravity: quarter the gravity, double the time.
2. Impact speed — v = g × t = √(2gh). Speed scales as the square root of gravity: on the Moon (0.166 g) impact speed is about 41% of Earth’s.

Reference times for a 100 m fall:

Two derived outputs round out the table: the slowest fall (Ceres, 26.7 s) and the fastest (the Sun, 0.85 s). The same kinematics power our acceleration calculator — falling is just constant acceleration from rest.

The same 100-metre drop unfolds very differently from one world to the next. The table below lists the NASA surface gravity for all fourteen bodies this tool covers, the local gravity relative to Earth, the vacuum fall time from 100 m, and the escape velocity needed to leave each world.

Notice the spread: on Ceres the same fall takes about 26.7 seconds — long enough for a short conversation on the way down — while on the Sun it is over in under a second. The Moon sits at 11.1 seconds, roughly 2.5 times the Earth value of 4.52 seconds, because lunar gravity is about one-sixth of ours.

The escape-velocity column explains why missions to small worlds are cheap in fuel: at 0.5 km/s on Ceres, a strong athletic throw would come surprisingly close to leaving the body entirely. On the giant planets, by contrast, no chemical rocket launched from the cloud tops would reach orbit unaided.

1. Enter the fall height in metres (1 to 10,000).
2. Click "Calculate fall time" to run the kinematics.
3. Read the fall time and impact speed for each of the 14 bodies.
4. Compare the slowest (Ceres) and fastest (Sun) falls at the bottom.
5. Note that times are vacuum values; thick atmospheres change real results.

Why does the Moon take so much longer to fall?

Fall time is t = √(2h/g). The Moon’s gravity is 16.6% of Earth’s, so the time is √(1/0.166) ≈ 2.46× longer: 11.1 s versus 4.5 s for 100 m. Lower gravity, slower acceleration, longer fall.

How fast do you hit the ground on Jupiter?

For a 100 m fall, impact speed on Jupiter is about 70.4 m/s = 253 km/h, because its surface gravity is 2.53× Earth’s and speed scales as √(2gh). That is roughly 1.6× the Earth impact speed.

Does air resistance change these numbers?

Yes, but only on worlds with thick atmospheres. On Earth, terminal velocity caps skydivers at ~200 km/h, so long falls take longer than the vacuum formula. On the Moon, Mercury or Pluto there is no air, so the formula is exact.

Is a 100 m fall survivable on Pluto?

The vacuum impact speed is 40 km/h — in the range of survivable car-crash speeds, though other factors (suit, landing surface, body position) decide reality. On Earth the same fall hits at 159 km/h, which is almost always fatal.

What height is needed for a 1-second fall on Mars?

Solve h = ½gt² with g = 3.71 m/s² and t = 1 s: h ≈ 1.86 m. On Earth the same 1-second fall needs 4.9 m, and on the Moon just 0.81 m. The same tool answers this by entering different heights.

Air resistance matters once heights exceed a few hundred metres on Earth: a skydiver reaches terminal velocity (~200 km/h) after about 12 seconds, so a 4,000 m jump takes roughly 60-90 s in reality, not the vacuum value of 28.6 s. On airless worlds (Moon, Mercury, Pluto, Ceres) the vacuum formula is exact — there is no atmosphere to slow you. On Venus and Titan the thick atmosphere would cap the speed far below the vacuum estimate. For survival questions, impact speed is the number that matters: roughly 40-60 km/h is survivable in a car crash, which means the 100 m fall on Pluto ends at 40 km/h — theoretically survivable, while the same fall on Earth at 159 km/h is not. If you plan Moon jumps, remember you have more airtime: reaction time is unchanged, so catching yourself is no easier. For the physics of motion in general, pair this with the speed, distance and time calculator.

Real falls on worlds with atmospheres end sooner than the vacuum maths suggests, because drag caps the speed at a terminal velocity where air resistance balances weight. A belly-down skydiver on Earth stabilises near 55 m/s; on Titan, whose dense nitrogen air meets one-seventh of our gravity, terminal velocity falls to a survivable 6-7 m/s — the textbook example of a moon where a fall from an aircraft might be walk-away. The Apollo 15 hammer-and-feather drop remains the cleanest proof of the vacuum model used here: with no air to slow either object, both hit the lunar dust at the same instant. One caveat when comparing the giant planets: their quoted surface gravity refers to the 1-bar pressure level in the cloud tops, so a fall there is a thought experiment about a cloud deck, not solid ground.