Speed and Velocity Conversions: Complete Guide to MPH, KM/H, M/S & More

Speed conversions are essential for driving, aviation, sports, and scientific applications. Whether you're converting between miles per hour and kilometers per hour for international travel, understanding knots for maritime or aviation use, or working with meters per second in physics, accurate speed conversions are crucial.

Quick Answer: Use our unit converter for instant, accurate conversions. We support all major measurement types including length, weight, volume, temperature, and more.

This comprehensive guide covers all speed and velocity conversions you'll need, with practical examples and conversion tables.

Understanding Speed Units

Miles per Hour (mph)

Miles per hour is the standard speed unit in the United States, used for:

• Road speed limits
• Vehicle speedometers
• Weather reports (wind speed)
• Sports (running, cycling)

Common Speeds:

• City speed limit: 25-35 mph
• Highway speed limit: 55-75 mph
• Running speed: 5-10 mph
• Cycling speed: 10-20 mph

Convert mph to other units with our speed converter.

Kilometers per Hour (km/h)

Kilometers per hour is used in most countries worldwide, including:

• Europe
• Asia
• Australia
• Canada
• Most of Latin America

Common Speeds:

• City speed limit: 50 km/h
• Highway speed limit: 100-130 km/h
• Running speed: 8-16 km/h
• Cycling speed: 16-32 km/h

Convert km/h to mph using our speed converter.

Meters per Second (m/s)

Meters per second is commonly used in:

• Physics and scientific calculations
• Engineering
• Some sports (track and field)
• Wind speed measurements

Common Speeds:

• Walking: 1-1.5 m/s
• Running: 3-5 m/s
• Wind speed: 5-15 m/s
• Sound speed: 343 m/s (at sea level)

Use our speed converter for m/s conversions.

Speed Conversion Formulas

Miles per Hour to Kilometers per Hour

Formula: km/h = mph × 1.609344

Common Conversions:

• 30 mph = 48.3 km/h
• 50 mph = 80.5 km/h
• 60 mph = 96.6 km/h
• 70 mph = 112.7 km/h
• 100 mph = 160.9 km/h

Mental Math: Multiply mph by 1.6 for approximate km/h

• 60 mph × 1.6 = 96 km/h (actual: 96.6 km/h)

Convert mph to km/h instantly with our speed converter.

Kilometers per Hour to Miles per Hour

Formula: mph = km/h ÷ 1.609344

Common Conversions:

• 50 km/h = 31.1 mph
• 80 km/h = 49.7 mph
• 100 km/h = 62.1 mph
• 120 km/h = 74.6 mph
• 130 km/h = 80.8 mph

Mental Math: Multiply km/h by 0.6 for approximate mph

• 100 km/h × 0.6 = 60 mph (actual: 62.1 mph)

Convert km/h to mph with our speed converter.

Meters per Second Conversions

To km/h: km/h = m/s × 3.6

• 10 m/s = 36 km/h
• 25 m/s = 90 km/h

To mph: mph = m/s × 2.237

• 10 m/s = 22.4 mph
• 25 m/s = 55.9 mph

Use our speed converter for m/s conversions.

Speed Conversion Tables

Common Speed Conversions

mph	km/h	m/s	Description
5	8	2.2	Walking
10	16	4.5	Fast walking
15	24	6.7	Jogging
20	32	8.9	Running
25	40	11.2	City speed limit (US)
30	48	13.4	City speed limit
50	80	22.4	Highway speed limit
60	97	26.8	Highway speed limit (US)
70	113	31.3	Highway speed limit
100	161	44.7	High-speed highway

International Speed Limits

United States

Common Speed Limits:

• Residential: 25-35 mph
• City streets: 30-45 mph
• Highways: 55-75 mph
• Some interstates: 80 mph (Texas, Montana)

Convert US speed limits using our speed converter.

Europe

Common Speed Limits:

• City/urban: 50 km/h (31 mph)
• Rural roads: 80-90 km/h (50-56 mph)
• Highways: 100-130 km/h (62-81 mph)
• Germany (autobahn): Often no limit, but recommended 130 km/h (81 mph)

Other Countries

Australia/New Zealand:

• Urban: 50-60 km/h (31-37 mph)
• Highways: 100-110 km/h (62-68 mph)

Canada:

• Urban: 50 km/h (31 mph)
• Highways: 100-110 km/h (62-68 mph)

Use our speed converter to understand speed limits when traveling.

Nautical and Aviation Speeds

Knots (kn)

Knots are used in:

• Maritime navigation
• Aviation
• Meteorology (wind speed)

Conversion: 1 knot = 1.15078 mph = 1.852 km/h

Common Speeds:

• Slow boat: 5-10 knots
• Fast boat: 20-30 knots
• Commercial aircraft: 450-550 knots (cruise)
• Wind speed: Measured in knots

Convert knots with our speed converter.

Mach Number

Mach number represents speed relative to the speed of sound:

• Mach 1 = Speed of sound ≈ 767 mph (at sea level)
• Used for: Aircraft, missiles, high-speed vehicles

Common Mach Speeds:

• Subsonic: < Mach 1
• Transonic: Mach 0.8-1.2
• Supersonic: > Mach 1
• Hypersonic: > Mach 5

Speed of Sound:

• At sea level: 767 mph = 1,235 km/h = 343 m/s
• Varies with altitude and temperature

Use our speed converter for Mach conversions.

Sports Speed Conversions

Running Speeds

Pace Conversions:

• 5 min/km = 8 min/mile = 12 km/h = 7.5 mph
• 6 min/km = 9.7 min/mile = 10 km/h = 6.2 mph
• 7 min/km = 11.3 min/mile = 8.6 km/h = 5.3 mph

World Records:

• 100m sprint: ~37 km/h (23 mph)
• Marathon: ~20 km/h (12.4 mph)
• Mile run: ~24 km/h (15 mph)

Cycling Speeds

Common Cycling Speeds:

• Casual: 15-20 km/h (9-12 mph)
• Recreational: 20-25 km/h (12-16 mph)
• Training: 25-30 km/h (16-19 mph)
• Racing: 40-50 km/h (25-31 mph)
• Professional: 50+ km/h (31+ mph)

Vehicle Speeds

Car Types:

• City car: 0-100 km/h in 10-15 seconds
• Sports car: 0-100 km/h in 3-5 seconds
• Top speeds: 200-300+ km/h (124-186+ mph)

Convert any sports speed with our speed converter.

Physics and Scientific Speeds

Speed of Light

Speed of Light: 299,792,458 m/s = 1,079,252,848.8 km/h = 670,616,629.4 mph

Relativity: Nothing can travel faster than light in a vacuum.

Escape Velocities

Earth's Escape Velocity: 11.2 km/s = 40,320 km/h = 25,037 mph

Other Celestial Bodies:

• Moon: 2.38 km/s
• Mars: 5.03 km/s
• Jupiter: 59.5 km/s

Terminal Velocity

Human Terminal Velocity (skydiving):

• Belly-down: ~195 km/h (121 mph) = 54 m/s
• Head-down: ~320 km/h (199 mph) = 89 m/s

Wind Speed Conversions

Wind Speed Scales

Beaufort Scale (approximate):

• Light breeze: 6-11 km/h (4-7 mph) = 2-3 m/s
• Moderate breeze: 20-28 km/h (13-18 mph) = 6-8 m/s
• Fresh breeze: 29-38 km/h (19-24 mph) = 8-11 m/s
• Strong breeze: 39-49 km/h (25-31 mph) = 11-14 m/s
• Gale: 62-74 km/h (39-46 mph) = 17-21 m/s
• Storm: 89-102 km/h (55-63 mph) = 25-28 m/s
• Hurricane: 119+ km/h (74+ mph) = 33+ m/s

Convert wind speeds with our speed converter.

Practical Speed Conversion Examples

Example 1: Driving in Europe

Problem: US driver used to 60 mph, sees 100 km/h speed limit

Solution:

• 100 km/h = 62.1 mph
• Very similar to 60 mph, safe to drive at limit

Use our speed converter to check any speed limit.

Example 2: Running Pace

Problem: Runner wants 8 min/mile pace, what's that in min/km?

Solution:

• 8 min/mile = 1 mile per 8 minutes = 7.5 mph = 12 km/h
• 12 km/h = 1 km per 5 minutes
• Answer: 5 min/km

Example 3: Aircraft Speed

Problem: Aircraft cruising at 500 knots, what's that in mph?

Solution:

• 500 knots × 1.15078 = 575.4 mph
• Or use our speed converter

Essential Speed Conversion Tools

Use our comprehensive conversion tools:

• Speed Converter - mph, km/h, m/s, knots, Mach

Common Speed Conversion Mistakes

Mistake 1: Simple Multiplication

Problem: Converting 60 mph to 60 km/h by multiplying by 1 Solution: 60 mph = 96.6 km/h (multiply by 1.609)

Prevention: Always use our speed converter or the correct formula.

Mistake 2: Confusing mph and km/h

Problem: Thinking 100 km/h is the same as 100 mph Solution: 100 km/h = 62.1 mph (much slower!)

Prevention: Use our speed converter to verify conversions.

Mistake 3: Knots Confusion

Problem: Thinking 1 knot = 1 mph Solution: 1 knot = 1.151 mph = 1.852 km/h

Prevention: Use our speed converter for nautical speeds.

Quick Reference Card

Essential Conversions:

• 1 mph = 1.609 km/h
• 1 km/h = 0.621 mph
• 1 m/s = 3.6 km/h = 2.237 mph
• 1 knot = 1.151 mph = 1.852 km/h
• Speed of sound: 767 mph = 1,235 km/h = 343 m/s

Common Speeds:

• Walking: 3-5 km/h (2-3 mph)
• Running: 10-15 km/h (6-9 mph)
• City limit: 50 km/h (31 mph)
• Highway: 100-130 km/h (62-81 mph)

Frequently Asked Questions

What is the difference between metric and imperial systems?

The metric system uses base-10 units (meters, kilograms, liters) and is used worldwide. The imperial system uses inches, pounds, and gallons, primarily used in the United States. Metric is easier to convert because everything is in multiples of 10.

How do I convert units quickly in my head?

Use approximations: for km to miles multiply by 0.6, for kg to lbs multiply by 2, for Celsius to Fahrenheit double and add 30. These give rough estimates that are usually close enough for everyday use.

Why do different countries use different measurement systems?

Historical reasons. The US adopted the British Imperial system before the metric system was widely adopted. Most countries switched to metric in the 20th century for international trade and scientific consistency.

Related Articles

You might also find these guides helpful:

• Metric vs Imperial: Complete Comparison Guide for 2025: Understand the differences between metric and imperial systems. Learn when to use each, conversion formulas, and practical examples for length, weight, volume, and temperature.

• Temperature Conversion Master Guide: Celsius, Fahrenheit, Kelvin & More: Master temperature conversions with formulas, conversion tables, and practical examples. Learn Celsius, Fahrenheit, Kelvin conversions for cooking, science, and everyday use.

• Time Conversion Complete Guide: Seconds, Minutes, Hours, Days & More: Master time conversions between seconds, minutes, hours, days, weeks, months, and years. Essential for scheduling, calculations, and understanding time measurements.

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Conclusion

Understanding speed conversions is essential for driving, travel, sports, and scientific applications. Whether you're converting between mph and km/h for international travel, understanding knots for maritime use, or working with m/s in physics, accurate conversions ensure safety and precision.

Key Takeaways:

• mph to km/h: Multiply by 1.609
• km/h to mph: Multiply by 0.621
• Knots: 1 knot = 1.151 mph = 1.852 km/h
• Speed of sound: 767 mph = 1,235 km/h = 343 m/s

Use our speed converter for accurate conversions anytime. Whether you're planning a trip, understanding speed limits, or working on scientific calculations, our converter provides precise speed conversions for all your needs!