# Convertitore di velocità

> Converti mph in km/h, km/h in mph, m/s e nodi con fattori esatti, oltre a ft/s, Mach al livello del mare e velocità della luce.

Versione interattiva: https://www.calcopenly.com/it/conversion/speed-converter
Argomento: Convertitori di unità

Each speed unit is a fixed number of metres per second. The road and sea units are exact: a mile per hour is 0.44704 m/s because the mile is 1,609.344 m, a kilometre per hour is 1/3.6 m/s, and a knot, one nautical mile per hour, is 1,852/3,600 m/s.

The default converts 60 mph to 96.56064 km/h, the figure a UK or US driver needs on metric roads. Sailors and pilots work in knots, and 1 knot is exactly 1.852 km/h.

Mach is fixed here at 340.294 m/s, the speed of sound in the International Standard Atmosphere at sea level and 15 °C, and results that use it are marked approximate because the real speed of sound falls with temperature. The speed of light is exactly 299,792,458 m/s by definition.

## Dati

- **Valore**: Un numero nell’unità di partenza, oppure accompagnato dalla propria unità
- **Da** (opzioni: metre per second (m/s), kilometre per hour (km/h), mile per hour (mph), knot (kn), foot per second (ft/s), kilometre per second (km/s), Mach (sea level) (Ma), speed of light (c))
- **A** (opzioni: metre per second (m/s), kilometre per hour (km/h), mile per hour (mph), knot (kn), foot per second (ft/s), kilometre per second (km/s), Mach (sea level) (Ma), speed of light (c))

## Risultati

- Valore convertito — risultato principale
- Conversione
- Fattore di conversione
- Esattezza

## Formula

$$
\begin{gathered} x_{\text{to}} = x_{\text{from}} \times \dfrac{f_{\text{from}}}{f_{\text{to}}} \\ f = \text{one unit expressed in } \text{m/s} \end{gathered}
$$

## Esempi svolti

### 60 mph in km/h

- Valore: 60 mph
- Da: mile per hour (mph)
- A: kilometre per hour (km/h)
- **Valore convertito: 96.56064 km/h**
- **Esattezza: Esatto**
- Fonte di verifica: 60 × 1609.344 m / 1000 = 96.56064 km/h (1 mi = 1609.344 m, NIST HB 44)

### 1 knot in km/h

- Valore: 1 kn
- Da: knot (kn)
- A: kilometre per hour (km/h)
- **Valore convertito: 1.852 km/h**
- Fonte di verifica: 1 knot = 1 nautical mile per hour = 1852 m/h (NIST SP 811 App. B)

### 100 km/h in m/s

- Valore: 100 km/h
- Da: kilometre per hour (km/h)
- A: metre per second (m/s)
- **Valore convertito: 27.7777777778 m/s**
- **Esattezza: Definizioni esatte, decimale periodico**
- Fonte di verifica: 100000 m / 3600 s = 250/9 (Python 3.8 fractions from the legal definitions)

### Speed of light in km/s

- Valore: 1 c
- Da: speed of light (c)
- A: kilometre per second (km/s)
- **Valore convertito: 299,792.458 km/s**
- Fonte di verifica: c = 299,792,458 m/s exactly (SI definition of the metre)

### Mach 1 at sea level (approximate)

- Valore: 1 Ma
- Da: Mach (sea level) (Ma)
- A: kilometre per hour (km/h)
- **Valore convertito: 1,225.0584 km/h**
- **Esattezza: Approssimato**
- Fonte di verifica: 340.294 m/s (ISA sea level, 15 °C) × 3.6 = 1225.0584 km/h

## Domande

### How do I convert mph to km/h?

Multiply by 1.609344: 60 mph × 1.609344 = 96.56064 km/h, and 70 mph is 112.65 km/h. The factor is exact because a mile is exactly 1,609.344 m. Multiplying by 1.6 is a mental shortcut that comes out 0.6% low; to go from km/h to mph, multiply by 0.621371.

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

Divide by 3.6, because an hour has 3,600 seconds and a kilometre 1,000 metres. 100 km/h is 27.78 m/s and 36 km/h is exactly 10 m/s. Multiply by 3.6 to go back: a sprinter at 10 m/s is running 36 km/h, or 22.37 mph.

### What is a knot in mph and km/h?

One knot is exactly 1.852 km/h, about 1.15078 mph or 0.514444 m/s. It is one nautical mile (1,852 m) per hour, the speed unit of shipping and aviation, so a 30-knot wind is 55.56 km/h or 34.52 mph.

### How fast is Mach 1?

In the International Standard Atmosphere at sea level (15 °C) it is 340.294 m/s, which is 1,225.06 km/h or 761.22 mph, the value this converter uses. The speed of sound depends on air temperature, so at 11 km altitude, where the standard atmosphere is −56.5 °C, Mach 1 is about 295 m/s or 1,062 km/h.

### Why is the speed of light an exact number?

Because the metre is defined from it. Since 1983 the metre has been the distance light travels in vacuum in 1/299,792,458 of a second, which fixes c at exactly 299,792,458 m/s, or 1,079,252,848.8 km/h. Converting c into any unit here is therefore exact.

### Quanto è preciso «Convertitore di velocità»?

La precisione dipende dai dati inseriti e dalle ipotesi del metodo. Il calcolo decimale usa 50 cifre significative, ma stime, metodi numerici e dati di origine possono essere meno precisi; l’arrotondamento visualizzato non elimina questi limiti. Esempi svolti verificati con fonti indipendenti: 5. Per esempio, «60 mph in km/h» viene verificato con 60 × 1609.344 m / 1000 = 96.56064 km/h (1 mi = 1609.344 m, NIST HB 44).

### Da dove proviene il metodo?

NIST SP 811 (2008), Guide for the Use of the SI, Appendix B — conversion factors; NIST Handbook 44, Appendix C — General tables of units of measurement.

## Fonti

- [NIST SP 811 (2008), Guide for the Use of the SI, Appendix B — conversion factors](https://www.nist.gov/pml/special-publication-811)
- [NIST Handbook 44, Appendix C — General tables of units of measurement](https://www.nist.gov/pml/owm/nist-handbook-44-current-edition)