UFOZoo

Speed Converter — Convert km/h, mph, m/s, Knots, Mach

Convert between kilometers per hour, miles per hour, meters per second, knots, feet per second, and Mach number. Essential for travel and aviation.

Features

  • ✓Convert between speed units: km/h, mph, m/s, knots, ft/s, Mach
  • ✓Support for common speed units used in travel, aviation, maritime, and physics
  • ✓Instant conversion as you type
  • ✓Precise calculations with up to 6 significant figures
  • ✓Clear unit symbols and names for easy identification
  • ✓Swap units with one click to reverse the conversion
  • ✓Copy results to clipboard for use in other applications
  • ✓Works offline — all calculations happen in your browser

How to Use

  1. 1Enter a value in the input field. The result updates instantly.
  2. 2Choose the source unit and target unit using the dropdowns.
  3. 3Click the swap button (⇄) to reverse the conversion direction.
  4. 4Click the copy button to copy the result to your clipboard.
  5. 5Plan a road trip across countries — convert 120 km/h (European highway) to mph to know your speed in MPH-limited zones.
  6. 6Check aircraft performance — convert 250 knots (typical approach speed) to km/h or m/s for aviation calculations.
  7. 7Understand weather reports — convert wind speeds from knots to km/h or mph to better interpret storm forecasts.
  8. 8Convert running or cycling speeds — enter 4 min/km pace to see your speed in km/h, mph, and m/s.
  9. 9Compare speed limits globally — convert 65 mph (US highway) to km/h to see it equals ~105 km/h.
  10. 10Use Mach number conversion to understand supersonic vs subsonic speeds — enter Mach 2 to see 2,470 km/h.

Frequently Asked Questions

What units are supported?

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Kilometer per hour (km/h), Mile per hour (mph), Meter per second (m/s), Knot (kn), Foot per second (ft/s), and Mach number (Ma). These cover most common speed units used in travel, aviation, maritime, and physics.

What is a knot?

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A knot is a unit of speed equal to one nautical mile per hour, exactly 1.852 km/h. It's used in maritime and aviation contexts. For example, ship speeds and wind speeds in meteorology are often measured in knots.

What is Mach number?

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Mach number is the ratio of an object's speed to the speed of sound. Mach 1 = speed of sound (343 m/s at sea level, 20°C). Subsonic: < Mach 1, Supersonic: > Mach 1, Hypersonic: > Mach 5. Used in aviation and aerospace.

How accurate are the conversions?

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All conversions use precise conversion factors defined by international standards. Results are displayed with up to 6 significant figures. Mach number uses the speed of sound at sea level (343 m/s at 20°C).

Is my data sent to a server?

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No. All calculations happen entirely in your browser using JavaScript. Your input values are never transmitted over the network. The tool works offline after the page loads.

How do I convert wind speed from knots to mph?

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Wind speed in meteorology is often reported in knots (nautical miles per hour). 1 knot = 1.151 mph. To convert, multiply knots by 1.151. For example, 20 knots = 23 mph. For km/h, multiply by 1.852. The tool handles all these conversions instantly.

What is the speed of sound in different units?

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At sea level and 20°C, the speed of sound is: 343 m/s, 1,235 km/h, 767 mph, 667 knots, or 1,125 ft/s. Mach 1 = this speed. The exact value varies with temperature and altitude — colder air = slower sound. This tool uses the standard sea-level value.

How fast is Mach 2 in km/h and mph?

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Mach 2 is twice the speed of sound. At sea level: Mach 2 = 2,470 km/h ≈ 1,535 mph. This is typical for supersonic jets like the Concorde. Mach 3 (scramjet range) ≈ 3,705 km/h ≈ 2,302 mph. The tool converts all Mach values using standard conditions.

What's the difference between km/h and knots?

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1 knot = 1 nautical mile per hour = 1.852 km/h exactly. Nautical miles are based on Earth's circumference (1 minute of latitude), making them natural for navigation. Km/h is based on the metric kilometer. Boats and planes use knots; cars use km/h or mph.

How do I convert from m/s to km/h?

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Multiply m/s by 3.6 to get km/h. For example, 10 m/s = 36 km/h. To convert km/h to m/s, divide by 3.6. This is a common conversion in physics problems, track and field (sprint speeds), and wind measurement. The tool makes it instant.

What is the fastest speed ever recorded?

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The fastest manned aircraft is the X-15 at Mach 6.72 (7,274 km/h). The Parker Solar Probe is the fastest human-made object at ~692,000 km/h (Mach 560) relative to the Sun. In everyday units, the land speed record is 1,228 km/h (Thrust SSC, supersonic car).

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