# Convertitore di potenza

> Converti hp in kW, kW in hp, watt in cavalli e BTU/h in tonnellate di refrigerazione, distinguendo il cavallo meccanico (745.7 W) da quello metrico (735.5 W).

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

Every power unit is a fixed number of watts (joules per second). Mechanical horsepower is 550 foot-pounds-force per second, which works out at exactly 745.69987158227022 W; metric horsepower (PS) is 75 kilogram-force metres per second, exactly 735.49875 W. A ton of refrigeration is 12,000 BTU/h, about 3.517 kW.

The default converts a 100 hp engine to 74.57 kW. Car specifications are the usual reason: European registration documents give engine power in kW while brochures quote PS or hp, and 100 kW is 134.1 hp or 136.0 PS.

Air-conditioner ratings in BTU/h or tons describe cooling output, not the electricity drawn: a 1.5-ton unit moves 18,000 BTU/h (5.28 kW) of heat, and its electrical input depends on its efficiency rating.

## Dati

- **Valore**: Un numero nell’unità di partenza, oppure accompagnato dalla propria unità
- **Da** (opzioni: watt (W), milliwatt (mW), kilowatt (kW), megawatt (MW), gigawatt (GW), horsepower (hp), metric horsepower (PS), BTU per hour (BTU/h), ton of refrigeration (TR), kilocalorie per hour (kcal/h))
- **A** (opzioni: watt (W), milliwatt (mW), kilowatt (kW), megawatt (MW), gigawatt (GW), horsepower (hp), metric horsepower (PS), BTU per hour (BTU/h), ton of refrigeration (TR), kilocalorie per hour (kcal/h))

## Risultati

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

## Formula

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

## Esempi svolti

### 100 hp in kW

- Valore: 100 hp
- Da: horsepower (hp)
- A: kilowatt (kW)
- **Valore convertito: 74.5699871582 kW**
- **Esattezza: Esatto**
- Fonte di verifica: 1 hp = 550 ft·lbf/s = 550 × 0.3048 × 4.4482216152605 W = 745.69987158227022 W (NIST SP 811 App. B)

### 1 kW in hp

- Valore: 1 kW
- Da: kilowatt (kW)
- A: horsepower (hp)
- **Valore convertito: 1.3410220896 hp**
- Fonte di verifica: 1000 / 745.69987158227022 (Python 3.8 fractions from the legal definitions)

### 12,000 BTU/h is one ton of refrigeration

- Valore: 12,000 BTU/h
- Da: BTU per hour (BTU/h)
- A: ton of refrigeration (TR)
- **Valore convertito: 1 TR**
- Fonte di verifica: 1 ton of refrigeration = 12,000 BTU/h (NIST SP 811 App. B)

### Zero power

- Valore: 0 W
- Da: watt (W)
- A: horsepower (hp)
- **Valore convertito: 0 hp**
- **Esattezza: Esatto**
- Fonte di verifica: 0 × any factor = 0

### 1 metric horsepower in watts

- Valore: 1 PS
- Da: metric horsepower (PS)
- A: watt (W)
- **Valore convertito: 735.49875 W**
- Fonte di verifica: 1 PS = 75 kgf·m/s = 75 × 9.80665 W = 735.49875 W

## Domande

### How many watts are in a horsepower?

745.7 W for mechanical horsepower (550 ft·lbf/s), 735.5 W for metric horsepower (PS or CV), and exactly 746 W for the electric horsepower used to rate electric motors; NIST SP 811 lists all three. Mechanical and metric horsepower differ by 1.4%, enough to matter when comparing car figures.

### How do I convert kW to hp?

Multiply by 1.34102 for mechanical horsepower or by 1.35962 for metric PS. A 150 kW engine is 201.2 hp or 203.9 PS. To go from hp to kW, multiply by 0.7457, so the default 100 hp is 74.57 kW.

### What is the difference between hp, bhp and PS?

hp and bhp use the same 745.7 W unit; “brake” horsepower means the power was measured at the engine's output shaft, before transmission losses. PS (Pferdestärke) is metric horsepower, 735.5 W, also written CV or ch. A car quoted at 150 PS makes 147.9 hp or 110.3 kW.

### What does a 1.5-ton air conditioner mean?

It removes 18,000 BTU of heat per hour, which is 5.28 kW of cooling. A ton of refrigeration is 12,000 BTU/h, the rate that melts one short ton (2,000 lb) of ice in 24 hours, because ice absorbs 144 BTU per pound as it melts. The electricity it draws is lower and depends on its efficiency rating.

### How many BTU/h is 1 kW?

3,412.14 BTU/h. One watt is 3.41214 BTU/h, so a 2 kW electric heater gives out 6,824 BTU/h, and a 12,000 BTU/h air conditioner is rated at 3.517 kW of cooling. The factor is the same as between kWh and BTU because both sides are divided by one hour.

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

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, «100 hp in kW» viene verificato con 1 hp = 550 ft·lbf/s = 550 × 0.3048 × 4.4482216152605 W = 745.69987158227022 W (NIST SP 811 App. B).

### 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)