Speed Converter

Precision conversion for velocity units: from everyday km/h and mph to Mach numbers, Knots, and relativistic speeds (c).

Use Cases for this Tool

  • Driving & Travel: Convert miles per hour to kilometers per hour for speed limits and vehicle speedometers.
  • Aviation & Navigation: Convert between knots, mph, and km/h for aircraft speeds and maritime navigation.
  • Sports & Fitness: Track running pace, cycling speed, and athletic performance in different speed units.

Did you know?

The Parker Solar Probe reached speeds of 692,000 km/h (430,000 mph) in 2024, making it the fastest human-made object ever. That's fast enough to travel from New York to Tokyo in under 2 minutes!

Mastering Speed: From Daily Commutes to Cosmic Velocity

Speed is the fundamental measure of how fast an object moves. In 2026, the range of human experience with speed has never been wider—from the silent acceleration of electric vehicles to the hypersonic re-entry of spacecraft. Our converter provides scientific-grade precision for all your velocity calculations, whether you're a pilot, engineer, or student.

Related tools: Length Converter, Temperature Converter, Time Zone Converter, and Trip Cost Calculator.

Speed Constants & Records (2026 Update)

Understanding speed requires context. Here are the benchmarks defining our modern understanding of velocity:

Hypersonic & Space

The Parker Solar Probe is the fastest object ever built, utilizing gravity assists to reach a staggering 692,000 km/h (430,000 mph). Meanwhile, commercial hypersonic travel (Mach 5+) is on the horizon for 2030.

EV Performance

Electric powertrains offer instant torque. The Rimac Nevera and its successors have redefined automotive performance, surpassing 412 km/h (256 mph) and proving EVs are the new kings of speed.

The Complexity of Mach 1

While most units like km/h or mph are constant, Mach is dynamic. It represents the ratio of an object's speed to the speed of sound in the surrounding fluid (air).

  • Sea Level (20°C): Mach 1 ≈ 1,235 km/h (767 mph).
  • Cruising Altitude (35,000 ft, -54°C): Mach 1 drops to ≈ 1,060 km/h (659 mph) because sound travels slower in cold air.

Pro Tip: When pilots fly at "Mach 0.85", they are flying at 85% of the local speed of sound. This ensures they stay within the safe aerodynamic limits of the aircraft frame.

Essential Unit Definitions

Knots (kn)

Used in aviation and maritime navigation. One knot is one nautical mile (1,852 meters) per hour. A nautical mile equals one minute of latitude.

Lightspeed (c)

The universal speed limit: 299,792,458 m/s. Following relativity, as an object approaches 'c', its mass becomes infinite.

Comparative Speed Table

Object / PhenomenonSpeed (approx.)Mach Equivalent
Fastest Sprinter44.72 km/h~ Mach 0.03
Commercial Jet900 km/hMach 0.75 - 0.85
F-35 Fighter Jet1,960 km/hMach 1.6
ISS Orbit27,600 km/hMach 22.3
Parker Solar Probe692,000 km/hMach 560+

Common Speed Conversions

Quickly lookup conversions for popular speed queries, including the speed of sound, common highway speeds, and aviation metrics.

MPHkm/hKnotsContext / Note
62 mph100 km/h54 ktsStandard 0-100 km/h benchmark
110 mph177 km/h96 ktsHigh-speed train / Autobahn
113 mph182 km/h98 kts-
118 mph190 km/h103 ktsCommon Tire Speed Rating (T)
129 mph208 km/h112 kts-
150 mph241 km/h130 ktsPerformance Car Top Speed
241 mph388 km/h209 ktsMcLaren F1 Top Speed
660 mph1,062 km/h574 ktsTransonic Region
767 mph1,235 km/h667 ktsSpeed of Sound (Mach 1)
920 mph1,481 km/h799 ktsMach 1.2 (Supersonic)
20,500 mph32,991 km/h17,814 ktsOrbital Re-entry Speed

Frequently Asked Questions

How do I convert mph to km/h?
To convert mph to km/h, multiply the speed in mph by 1.609344. For example, 60 mph × 1.609344 ≈ 96.56 km/h. This exact conversion factor is standard for all automotive and scientific applications.
What is the fastest man-made object in 2026?
As of 2026, the Parker Solar Probe holds the speed record, reaching velocities exceeding 692,000 km/h (430,000 mph) during its closest solar approaches. This is fast enough to travel from New York to Tokyo in under 2 minutes.
Does Mach 1 speed change with altitude?
Yes, Mach 1 (the speed of sound) depends on air temperature, which drops with altitude. At sea level (20°C), Mach 1 is ~1,235 km/h (767 mph). At 30,000 feet (-44°C), it drops to ~1,093 km/h (679 mph).
What is 1 Knot in mph and km/h?
1 Knot (kn) equals exactly 1.852 km/h or approximately 1.15078 mph. It is based on the nautical mile, which corresponds to one minute of latitude on Earth's surface.
How fast is the speed of light (c) compared to sound?
Light travels at 299,792,458 m/s in a vacuum, while sound travels at roughly 343 m/s in air. This means light is nearly 874,000 times faster than sound.
What is the top speed of 2026 electric hypercars?
Modern electric hypercars like the Rimac Nevera and spark-tech prototypes have achieved speeds over 412 km/h (256 mph), with 0-100 km/h acceleration times under 1.8 seconds.
What is 767 mph in km/h?
767 mph is equal to approximately 1,234.4 km/h. This is a significant number because it represents the speed of sound (Mach 1) at standard sea level conditions (20°C).
How fast is Mach 1.2 in mph?
Mach 1.2 is 1.2 times the speed of sound. At sea level, this equals about 920.4 mph (1,481 km/h). This is considered a supersonic speed often achieved by fighter jets.
Convert 118 mph to km/h
118 mph converts to roughly 189.9 km/h. This is a common top speed limiter for many standard passenger vehicles.

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