How long does it take an object to fall a given distance?

For an object released from rest, the fall time is t = √(2h ÷ g). On Earth that means a 10 metre drop takes about 1.43 seconds, a 50 metre drop about 3.19 seconds and a 100 metre drop about 4.52 seconds. Notice the time does not double when the height doubles — because distance grows with the square of time, you need four times the height to double the fall time.

How fast is something moving when it lands?

Impact speed from rest is v = √(2gh), and with a starting speed it becomes v = √(v₀² + 2gh). A 10 metre drop produces about 14 m/s, roughly 50 km/h. The Leaning Tower of Pisa at 55.9 metres gives about 33 m/s or 119 km/h. Speed grows with the square root of height, so a drop four times as tall only doubles the landing speed.

Do heavy objects fall faster than light ones?

Not in a vacuum. Gravity accelerates every object at the same rate regardless of mass, so a hammer and a feather released together hit the ground together — as Apollo 15 astronaut David Scott famously demonstrated on the Moon. Mass simply cancels out of the equations. On Earth the feather loses because air resistance affects it far more than the hammer, not because it weighs less.

What is Galileo's odd-number rule?

An object released from rest covers distances in successive equal time intervals that follow the ratio 1 : 3 : 5 : 7 : 9. On Earth that is 4.905 m in the first second, 14.715 m in the second, 24.525 m in the third, and so on. Galileo discovered this by rolling balls down inclined ramps, slowing the motion enough to time it, and it was the first clear evidence that falling is uniformly accelerated rather than moving at a constant speed.

Why is Earth's gravity 9.81 m/s², and does it vary?

The figure comes from Earth's mass and radius, and 9.81 m/s² is the standard average value. It does vary slightly: gravity is a little stronger at the poles, where you sit closer to Earth's centre, and a little weaker at the equator, where the planet bulges and rotation works against you. The range runs from roughly 9.78 to 9.83 m/s². Altitude reduces it too, but the effect is tiny — even at the top of Everest it drops by only about 0.3 percent.

How does gravity elsewhere in the solar system change the fall?

Fall time scales as 1/√g while impact speed scales as √g. Lunar gravity of 1.62 m/s² is about a sixth of Earth's, so the same drop takes roughly 2.5 times as long and lands at about 40 percent of the speed. On Mars, at 3.72 m/s², the fall takes around 1.6 times as long. Jupiter reverses it: at 24.79 m/s² an object falls in roughly two-thirds the time and hits about 1.6 times faster.

What happens if the object is thrown down or thrown up first?

A downward throw simply adds to the starting speed, so the object lands sooner and harder — the impact speed becomes √(v₀² + 2gh). An upward throw is more interesting: the object decelerates, stops for an instant at a peak v₀²÷(2g) above the release point, then falls back. It passes the release point moving downward at exactly its original throwing speed, and from there the rest of the fall is identical to a simple drop.

How much does air resistance change these numbers?

This calculator models a vacuum, so the figures are an upper bound. In real air an object stops accelerating once drag grows to balance its weight, and it then falls at a constant terminal velocity. A compact dense object over a short drop matches the ideal numbers closely, but over a long fall the gap becomes large — the ideal model would predict speeds that real objects never reach. The lighter and larger the object, the sooner drag takes over.

Why does distance grow as a curve while speed grows as a straight line?

Speed increases by the same amount every second — g m/s each second — so plotted against time it is a straight line. Distance is the running total of that ever-growing speed, so each second adds more than the last, which bends the graph upward into a parabola. Mathematically, distance is the area under the speed line, and the area of a triangle grows with the square of its width, which is exactly why h = ½gt².

Free Fall Calculator

Work out how long an object takes to fall, and how fast it is moving when it lands. Enter a drop height and this calculator returns the fall time and the impact speed in metres per second, kilometres per hour and miles per hour — then animates the drop so you can watch the object accelerate, scrub t...

THE DROP

HOW IT STARTS

DROP HEIGHT (m)

GRAVITY — 9.81 m/s²

DROP FROM

FALL TIME

4.52 s

IMPACT SPEED

44.3 m/s

That is 159.5 km/h · 99.1 mph

Drop height

100.00 m

Initial speed

0.00 m/s (rest)

Acceleration

9.81 m/s²

Time to peak

n/a

Speed after 1 s

9.81 m/s

Fallen in 1 s

4.91 m

FALL TIMELINE

TIME

FALLEN

SPEED

LEFT

0.75s

2.8m

7.4

97.2m

1.51s

11.1m

14.8

88.9m

2.26s

25.0m

22.1

75.0m

3.01s

44.4m

29.5

55.6m

3.76s

69.4m

36.9

30.6m

4.52s

100.0m

44.3

0.0m

STEPS

Released from rest, so the whole fall is driven by gravity alone: h = ½gt²

Rearranged: t = [−v₀ + √(v₀² + 2gh)] ÷ g = [-0.00 + √(0.00 + 1,962.00)] ÷ 9.81

Fall time: t = 4.5152 s

Impact speed: v = √(v₀² + 2gh) = √(1,962.00) = 44.2945 m/s

DROP SIMULATION

TIME

0.00 s

FALLEN

0.0 m

REMAINING

100.0 m

SPEED

0.0 m/s

Galileo's odd-number rule. Each bar is the distance covered in one equal slice of time. Released from rest the six bars grow as 1 : 3 : 5 : 7 : 9 : 11 — the odd numbers, which is the signature of constant acceleration and the pattern Galileo measured on inclined ramps four centuries ago. They sum to 36, or six squared, which is why the last slice alone covers almost a third of the whole drop.

SPEED vs TIME — straight line

DISTANCE vs TIME — curve

Speed climbs in a straight line — gravity adds 9.81 m/s every second. Distance curves upward, because it is the running total of an ever-growing speed.

THE SAME DROP ELSEWHERE

Earth

4.52s

Moon

11.11s

Mars

7.33s

Venus

4.75s

Jupiter

2.84s

Vacuum model. Gravity is the only force here — no air resistance. Real objects stop speeding up once drag balances their weight, and from tall drops the true impact speed is far lower than the ideal figure above.

Live simulation · drawn to scale · updates as you type

Created with❤️byeaglecalculator.com

HOW TO USE

1
Enter the DROP HEIGHT — the vertical distance from the release point down to the ground, in metres. Use the preset chips for familiar reference heights such as a diving board, the Leaning Tower of Pisa or the Empire State Building.
2
Choose how the motion starts. Released means the object begins at rest and gravity does all the work. Thrown down gives it a head start, so it lands sooner and faster. Thrown up makes it rise, stop, and then fall back past the release point.
3
Pick a planet if you want gravity other than Earth's 9.81 m/s², and use the M ⇄ FT button to switch the readout between metres and feet. All results update instantly as you type.
4
Read the fall time and impact speed in the black box, then study the simulation: press PLAY or REPLAY to watch the drop, or drag the scrubber to freeze any instant and read the distance fallen, speed and height remaining at that moment.

THE FORMULAS

Distance fallenh = v₀t + ½gt²

From resth = ½gt²

Speed at time tv = v₀ + gt

Speed from heightv = √(v₀² + 2gh)

Fall timet = [−v₀ + √(v₀² + 2gh)] / g

Fall time from restt = √(2h / g)

Rise before fallingpeak = v₀² / (2g)

Earth gravityg ≈ 9.81 m/s²

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Last updated: July 28, 2026 · Formula verified · Eagle-eyed accuracy for every calculation.