"How fast" is one of those questions where context helps. A 10 mph wind is mild for a person, lethal for a butterfly. Here's a table of speeds across nature and technology — useful for sanity-checking, building physics intuition, or settling debates.

Slow stuff

SpeedReference
3 mm/sSloth (slowest mammal)
13 mm/sGarden snail
30 mm/sEarthworm
0.04 mph (60 mm/s)Tortoise (galápagos)
0.5 mphStar-nosed mole tunneling

Walking and running

SpeedReference
3 mphCasual human walk
4–5 mphBrisk walk
6 mphSlow jog
10 mphAverage recreational runner
13 mphMarathon world record pace
23 mphUsain Bolt at peak (100m world record)
27 mphOlympic 100m hurdle runner

Animal top speeds

AnimalTop speed
Zebra40 mph
Lion50 mph
Greyhound45 mph
Antelope60 mph
Cheetah70 mph
Sailfish (fastest fish)68 mph
Spur-winged goose (fastest bird in level flight)88 mph
Peregrine falcon (in dive)240+ mph

Vehicles and machines

SpeedReference
15 mphBicycle (casual)
30 mphBicycle (racing)
50 mphCruise ship
65 mphU.S. interstate speed limit
110 mphMaglev train
186 mphBullet train (Shinkansen)
231 mphBugatti Chiron production car
250+ mphFormula 1 race car
580 mphBoeing 737 commercial cruise
670 mphSR-71 Blackbird (retired)
2,200 mphConcorde (retired)
17,500 mphInternational Space Station orbital velocity
25,000 mphEarth escape velocity (lunar mission)

Projectiles and bullets

SpeedReference
50 mphTennis serve (slow)
100 mphBaseball fastball (pro)
140 mphTennis serve (top pros)
200 mphHockey puck (slap shot)
700 mphPistol bullet (.22 LR)
1,700 mphRifle bullet (.308 Win)
3,300 mphTank gun shell
10,000+ mphHypersonic projectiles

Natural phenomena

SpeedReference
10 mphLight breeze
40 mphStrong wind
74 mphHurricane (Category 1 minimum)
157+ mphHurricane (Category 5)
200–300 mphTornado (EF5)
500 mphJet stream
800 mphEarth's rotational speed at equator
30 km/s (67,000 mph)Earth orbiting Sun
240 km/s (537,000 mph)Solar system orbiting galaxy center

Sound

Speed of sound varies by medium:

  • Air at 20°C: 343 m/s = 767 mph
  • Helium: 972 m/s (why your voice sounds high)
  • Water: 1,498 m/s = 3,350 mph
  • Wood: 3,000–4,000 m/s
  • Steel: 5,960 m/s = 13,300 mph
  • Diamond: 12,000 m/s

Sound moves about 4× faster in water than air, 17× faster in steel.

Light and electromagnetic waves

Speed of light in vacuum: 299,792,458 m/s = 670,616,629 mph = 186,282 mi/s.

Light from the Sun takes 8 minutes 20 seconds to reach Earth.

Light from the next-nearest star (Proxima Centauri) takes 4.3 years.

Light from across the visible universe took 13.8 billion years.

Speed of fastest fundamental phenomena

  • Speed of light in vacuum: 299,792,458 m/s (the universal cosmic speed limit)
  • Speed of light in fiber optic cable: ~200,000,000 m/s (200,000 km/s)
  • Wave propagation in water (longest tsunami): ~500–800 km/h
  • Earthquake P-wave through Earth: ~6,000 m/s

The speed-of-light implication

Light is unique — its speed in vacuum is the same regardless of source motion. A flashlight aimed forward from a moving car emits light at exactly c, not c + car speed. This counterintuitive fact is the foundation of Einstein's relativity.

Anything with mass cannot reach c. Particle accelerators get electrons to 99.999...% of c but never quite. Reaching c would require infinite energy.

Calculate speeds yourself

Our velocity calculator handles distance ÷ time conversions across all common units. Useful for sanity-checking sports stats, vehicle specifications, or any "how fast" question.