Enter Speed to Convert
Converted Speed
Result: –
Scientific Form: –
Grouped Digits: –
Overview
This Speed Converter allows you to convert instantly between dozens of common and advanced velocity units. Whether you're converting kilometers per hour (km/h) to miles per hour (mph), Mach speed to meters per second (m/s), or even comparing a speed to the speed of light — this tool covers it all.
Supported units include: m/s, km/h, mph, ft/s, knots, Mach, and advanced options such as: cm/s, mm/s, km/min, ft/min, ft/hr, mi/min, mi/s, in/min, in/hr, furlongs per fortnight, plus the physical constants: speed of sound and speed of light.
This tool is ideal for:
- Engineering, physics, and aerospace calculations
- Converting driving or biking speeds
- Aviation and marine navigation (knots, Mach)
- Scientific curiosity (compare to speed of light or sound)
Formula & Methodology
All conversions are done via the base unit: meters per second (m/s). The logic is:
- Convert your input to m/s using a predefined factor.
- Then convert m/s to your desired unit using the reverse factor.
For example:
60 mph × 0.44704 = 26.8224 m/s
26.8224 m/s ÷ 0.27777778 = 96.8 km/h
Some units are approximate and based on standard conditions. For example:
Mach 1 ≈ 343 m/s at sea level (20 °C), but ~295 m/s at cruising altitude (11 km).
The speed of light is exactly 299,792,458 m/s.
Examples
- 10 m/s → km/h: 10 ÷ 0.27777778 = 36 km/h
- 60 mph → m/s: 60 × 0.44704 = 26.8224 m/s
- 100 knots → km/h: 100 × 1.852 = 185.2 km/h
- 5 Mach → mph: 5 × 343 = 1715 m/s → ÷ 0.44704 = 3836.4 mph
- 50 mi/s → km/h: 50 × 1609.344 × 3.6 = 289,681.92 km/h
- 1 furlong/fortnight → m/s: ≈ 0.000166719 m/s
- Speed of light → mph: 299,792,458 ÷ 0.44704 ≈ 670,616,629 mph
| Unit | Value in m/s | Notes / Definition |
|---|---|---|
| Meters per second (m/s) | 1 | 1 m/s |
| Kilometers per hour (km/h) | 0.2777777778 | 1000 m / 3600 s |
| Miles per hour (mph) | 0.44704 | 1 mph = 1609.344 m / 3600 s |
| Feet per second (ft/s) | 0.3048 | 1 ft = 0.3048 m |
| Knots | 0.5144444444 | 1 knot = 1 nautical mile/3600 s = 1852 m/3600 s |
| Mach | 343 | Speed of sound ≈ 343 m/s (20 °C, sea level) |
| Feet per minute (ft/min) | 0.00508 | 0.3048 m / 60 s |
| Centimeters per second (cm/s) | 0.01 | 1 cm = 0.01 m |
| Millimeters per second (mm/s) | 0.001 | 1 mm = 0.001 m |
| Kilometers per minute (km/min) | 16.6666666667 | 1000 m / 60 s |
| Feet per hour (ft/hr) | 0.0000846667 | 0.3048 m / 3600 s |
| Miles per minute (mi/min) | 26.8224 | 1609.344 m / 60 s |
| Miles per second (mi/s) | 1609.344 | 1609.344 m / 1 s |
| Furlong per fortnight (fur/fortnight) | 0.000166719 | 1 furlong = 201.168 m, 1 fortnight = 1 209 600 s |
| Inch per hour (in/hr) | 0.0000070556 | 0.0254 m / 3600 s |
| Inch per minute (in/min) | 0.0004233333 | 0.0254 m / 60 s |
| Speed of sound (air, 20 °C) | 343 | ≈ 343 m/s at sea level; varies with temperature and altitude |
| Speed of light (vacuum) | 299792458 | Exact constant 299 792 458 m/s |
Use Cases
- Compare aircraft speeds to Mach and sound
- Convert workout or treadmill speeds (km/h ↔ mph)
- Check spacecraft speed in terms of km/s or fractions of c
- Convert historical or fantasy units (furlongs/fortnight)
Frequently Asked Questions
What is the difference between Mach and m/s?
Mach is a ratio to the speed of sound. Mach 1 ≈ 343 m/s at sea level, but varies with altitude and temperature.
Why is the speed of light included?
It helps illustrate how fast light is compared to everyday speeds. Also useful for physics or astrophysics calculations.
Can I use this tool offline?
Yes. Once the tool loads in your browser, it works without internet because all calculations happen client-side.
How accurate are the conversions?
All factors are based on standard scientific definitions. Results are accurate to several decimal places.
Why include funny units like furlongs per fortnight?
Furlongs per fortnight is a humorous but valid unit used in internet culture and some engineering jokes. It's fun and educational!
Can I use this for physics and aerospace engineering?
Yes! The tool supports units relevant to aviation (knots, Mach), physics (m/s, c), and more, making it useful for educational and technical work.
What is Mach 1 in km/h?
Mach 1 (343 m/s) ≈ 343 × 3.6 = 1234.8 km/h at 20 °C, sea level. At higher altitudes (e.g., 11 km), speed of sound drops to ≈ 295 m/s, so Mach 1 ≈ 1062 km/h.
How do I convert furlong per fortnight to m/s?
1 furlong = 201.168 m, and 1 fortnight = 14 days = 1 209 600 s, so 201.168 / 1 209 600 ≈ 0.000166719 m/s.
What is knots used for?
Knots measure nautical miles per hour and are used in aviation and marine navigation. 1 knot = 0.514444 m/s.
Can I use this on my phone?
Yes. On smaller screens, the two columns collapse into one, and you can still toggle Advanced Mode to reveal or hide extra units.