# Конвертер давления

> Переводите psi в bar, bar в psi, kPa, atm, hPa, mmHg и inHg для шин, погоды и артериального давления с точной цепочкой коэффициентов.

Интерактивная версия: https://www.calcopenly.com/ru/conversion/pressure-converter
Тема: Конвертеры единиц

Each pressure unit is a fixed number of pascals (newtons per square metre). The bar is exactly 100,000 Pa, the standard atmosphere 101,325 Pa and the torr 1/760 atm. The psi, one pound-force per square inch, is about 6,894.757 Pa, fixed exactly by the 1959 pound, standard gravity (9.80665 m/s²) and the 25.4 mm inch.

The default converts a 32 psi tyre pressure to 2.2063 bar. Weather maps use hectopascals (1 hPa = 1 mbar; standard sea-level pressure is 1,013.25 hPa), and blood pressure is recorded in millimetres of mercury.

Gauge and absolute readings convert with the same factor but are not interchangeable: a tyre gauge shows pressure above the surrounding air, so 32 psi on the gauge is about 46.7 psi absolute at sea level. The inch of mercury uses the conventional value at 0 °C and is marked approximate.

## Входные данные

- **Значение**: Число в исходной единице или с собственной единицей измерения
- **Из** (варианты: pascal (Pa), hectopascal (hPa), kilopascal (kPa), megapascal (MPa), бар, standard atmosphere (atm), pound per square inch (psi), millimetre of mercury (mmHg), torr (Torr), inch of mercury (inHg), kilogram-force per cm² (kgf/cm²))
- **В** (варианты: pascal (Pa), hectopascal (hPa), kilopascal (kPa), megapascal (MPa), бар, standard atmosphere (atm), pound per square inch (psi), millimetre of mercury (mmHg), torr (Torr), inch of mercury (inHg), kilogram-force per cm² (kgf/cm²))

## Результаты

- Переведённое значение — основной результат
- Перевод единиц
- Коэффициент пересчёта
- Точность

## Формула

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

## Примеры с решением

### 32 psi tyre pressure in bar

- Значение: 32 psi
- Из: pound per square inch (psi)
- В: бар
- **Переведённое значение: 2.2063223338 bar**
- Источник проверки: 1 psi = 4.4482216152605 N ÷ (0.0254 m)² (NIST SP 811 App. B); 32 psi = 8896443230521/4032250000000 bar (Python 3.8 fractions from the legal definitions)

### 1 atm in psi

- Значение: 1 atm
- Из: standard atmosphere (atm)
- В: pound per square inch (psi)
- **Переведённое значение: 14.6959487755 psi**
- Источник проверки: 101325 Pa ÷ 6894.757293168… Pa (Python 3.8 fractions from the legal definitions)

### 760 torr is 1 atm

- Значение: 760 Torr
- Из: torr (Torr)
- В: standard atmosphere (atm)
- **Переведённое значение: 1 atm**
- **Точность: Точно**
- Источник проверки: 1 torr = 101325/760 Pa by definition (NIST SP 811 App. B)

### 1 inHg (conventional value)

- Значение: 1 inHg
- Из: inch of mercury (inHg)
- В: pascal (Pa)
- **Переведённое значение: 3,386.389 Pa**
- **Точность: Приблизительно**
- Источник проверки: NIST SP 811 App. B.9: inch of mercury (0 °C) = 3.386389 E+03 Pa

## Вопросы

### How do I convert psi to bar?

Divide by 14.5038, or multiply by 0.0689476. A bar is 100,000 Pa and a psi 6,894.757 Pa, so 1 bar = 14.5038 psi. A 32 psi tyre is 2.2063 bar, and a 2.5 bar tyre is 36.26 psi.

### Is 1 bar the same as 1 atmosphere?

No, though they are within 1.3%. The bar is exactly 100,000 Pa, while the standard atmosphere is exactly 101,325 Pa, which is 1.01325 bar, 14.696 psi or 760 mmHg. The atmosphere was set to match average sea-level air pressure, which is why weather charts centre on 1,013.25 hPa.

### What is the difference between psig and psia?

psig is gauge pressure, measured relative to the surrounding air; psia is absolute pressure, measured from a vacuum. At sea level psia = psig + 14.696. Tyre and compressor gauges read psig, so a flat tyre shows 0 psig while still holding 14.7 psia of air. The converter treats both alike, so keep input and output the same kind.

### Are mmHg and torr the same?

Almost. A torr is exactly 1/760 of a standard atmosphere, 133.322368 Pa, while the conventional millimetre of mercury is 133.322387415 Pa; they differ by about 0.14 parts per million. For blood pressure the difference never matters: 120/80 mmHg is 16.0/10.7 kPa either way.

### How do I convert inches of mercury to hPa?

Multiply by 33.8639: 29.92 inHg is 1,013.2 hPa, the standard altimeter setting in US aviation. This converter uses the conventional inch of mercury at 0 °C, 3,386.389 Pa (NIST SP 811), and marks results that use it as approximate because mercury's density changes with temperature.

### Насколько точен «Конвертер давления»?

Точность зависит от введённых данных и допущений метода. Десятичная арифметика использует 50 значащих цифр, но оценки, численные методы и исходные данные могут быть менее точными; округление на экране не устраняет эти ограничения. Решённые примеры, проверенные по независимым источникам: 4. Например, «32 psi tyre pressure in bar» проверяется по источнику 1 psi = 4.4482216152605 N ÷ (0.0254 m)² (NIST SP 811 App. B); 32 psi = 8896443230521/4032250000000 bar (Python 3.8 fractions from the legal definitions).

### Откуда взята методика?

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.

## Источники

- [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)