Pressure Converter - Free Online Tool

Convert pressure units instantly. Support for 7+ units including Pascal, Kilopascal, Bar. Free calculator with accurate conversions, formula, and table.

💨 Pressure Converter

Select your units from the lists below

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From Unit

Pascal
Symbol: Pa

Kilopascal
Symbol: kPa

Bar
Symbol: bar

PSI
Symbol: psi

Atmosphere
Symbol: atm

Torr
Symbol: Torr

Millimeter of Mercury
Symbol: mmHg

To Unit

Pascal
Symbol: Pa

Kilopascal
Symbol: kPa

Bar
Symbol: bar

PSI
Symbol: psi

Atmosphere
Symbol: atm

Torr
Symbol: Torr

Millimeter of Mercury
Symbol: mmHg

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💨 Pressure Converter

Pressure measurements appear in engineering, meteorology, and scientific research. Convert between pascals, bars, PSI, atmospheres, and other pressure units instantly. Whether you're working in industrial processes, weather forecasting, or laboratory research, our converter handles the calculations.

💨 About Pressure

Pressure measures force applied per unit area—how much force acts on a surface. In the International System of Units (SI), pressure is measured in pascals (Pa), defined as one newton per square meter. From meteorology and aviation to engineering and medicine, pressure measurements are used across many fields. Different regions and industries use different units. The metric system (pascals, bars, kilopascals) dominates global science and most countries, while the imperial system (PSI, pounds per square inch) remains common in the United States for industrial applications. Working with both systems helps with international engineering projects, scientific collaboration, and industrial processes.

Understanding Pressure Measurement

Pressure is a derived physical quantity representing the force applied perpendicular to a surface per unit area. In the International System of Units (SI), pressure is measured in pascals (Pa), defined as one newton per square meter (1 Pa = 1 N/m²). The pascal is named after Blaise Pascal, the French scientist who made significant contributions to fluid mechanics and atmospheric pressure research. Since pressure is derived from force (newton) and area (square meter), and both are based on fundamental constants, the pascal inherits precision and reproducibility. Standard atmospheric pressure at sea level is approximately 101,325 pascals, or 101.325 kilopascals. The bar, equal to 100,000 pascals, is a non-SI unit commonly used in meteorology and industry.

📜 History & Context

The history of pressure measurement dates back to the 17th century, when scientists first began to understand that air has weight and exerts pressure. In 1643, Italian physicist Evangelista Torricelli invented the mercury barometer, demonstrating atmospheric pressure by measuring the height of mercury in a glass tube—about 760 millimeters at sea level. This was one of the first quantitative instruments for measuring pressure. Blaise Pascal built on Torricelli's work, conducting experiments that showed atmospheric pressure decreases with altitude. In 1648, Pascal's brother-in-law carried a barometer up the Puy de Dôme mountain in France, observing that the mercury column dropped as altitude increased. This demonstrated that pressure varies with elevation, a principle still used in altimetry today. The modern era of pressure measurement began with the development of the metric system and the International System of Units. In 1971, the 14th General Conference on Weights and Measures adopted "pascal" as the special name for the SI unit of pressure, replacing the designation "newton per square meter." Today, pressure measurement benefits from precise standards maintained by institutions like NIST and coordinated by BIPM, ensuring consistent and reproducible measurements worldwide.

✨ Fun Facts

• The pascal is named after Blaise Pascal, who demonstrated in 1648 that atmospheric pressure decreases with altitude by having a barometer carried up a mountain.
• Standard atmospheric pressure at sea level is approximately 101,325 pascals, which equals about 14.7 pounds per square inch (PSI) or 1.01325 bars.
• The bar, equal to 100,000 pascals, is very close to one atmosphere and is still widely used in meteorology for weather reporting and forecasting.
• Evangelista Torricelli invented the first mercury barometer in 1643, creating one of the earliest quantitative instruments for measuring atmospheric pressure.
• One atmosphere of pressure is roughly equivalent to the pressure exerted by a 10.3-meter column of water, which is why divers feel increased pressure at depth.

💡 Real-World Examples

• Weather forecasting: Meteorologists measure atmospheric pressure in millibars or hectopascals to predict weather patterns. Falling pressure often indicates approaching storms.
• Automotive systems: Tire pressure is measured in PSI or kilopascals depending on location. Converting between units helps maintain optimal tire pressure and vehicle safety.
• Industrial processes: Chemical plants and refineries monitor pressure in bars, pascals, or PSI. Converting between units helps with equipment compatibility and international standards.
• Aviation and aerospace: Aircraft altimeters use pressure measurements to determine altitude. Converting between units helps with international flight operations and navigation.
• Medical applications: Blood pressure is measured in millimeters of mercury (mmHg), while medical equipment may use pascals or PSI. Converting between units helps ensure accurate readings.
• Scuba diving: Divers monitor pressure in bars or PSI for tank pressure and depth calculations. Converting between units helps with international diving standards and safety.
• HVAC systems: Heating and air conditioning systems measure pressure in various units. Converting between units helps with system design, maintenance, and international equipment compatibility.
• Scientific research: Laboratory experiments measure pressure in pascals or atmospheres. Converting between units helps follow international protocols and report results.

🔧 Common Applications

• Meteorology and weather science: Atmospheric pressure measurements help with weather forecasting, storm prediction, and global weather data sharing. Converting between units helps coordinate international data.
• Engineering and manufacturing: Industrial processes, pipeline systems, and equipment design need accurate pressure measurements. Converting between units helps with safety and efficiency.
• Aviation and aerospace: Aircraft systems use pressure measurements for altitude determination, cabin pressurization, and navigation. Converting between units helps with international operations.
• Medical and healthcare: Blood pressure monitoring, respiratory equipment, and medical devices use various pressure units. Converting between units helps ensure patient care.
• Automotive and transportation: Tire pressure, engine systems, and hydraulic systems measure pressure in different units. Converting between units helps with maintenance and safety standards.

❓ Frequently Asked Questions

+ How do I convert PSI to pascals?

To convert pounds per square inch (PSI) to pascals (Pa), multiply the PSI value by 6,894.76. For example, 1 PSI equals 6,894.76 pascals, and 14.7 PSI (standard atmospheric pressure) equals approximately 101,325 pascals.

+ What is standard atmospheric pressure?

Standard atmospheric pressure at sea level is approximately 101,325 pascals, 101.325 kilopascals, 1.01325 bars, or 14.7 pounds per square inch (PSI). This is the average pressure exerted by Earth's atmosphere at sea level and serves as a reference point for many calculations.

+ How do I convert bars to pascals?

To convert bars to pascals, multiply the bar value by 100,000. For example, 1 bar equals 100,000 pascals, and 1.01325 bars (standard atmospheric pressure) equals 101,325 pascals. The bar is commonly used in meteorology and industry.

+ What is the difference between PSI and bar?

PSI (pounds per square inch) is an imperial unit, while bar is a metric unit. One bar equals approximately 14.5 PSI, or more precisely, 14.5038 PSI. PSI is commonly used in the United States, while bars are used in most other countries and in meteorology.

+ How do I convert atmospheres to pascals?

To convert atmospheres (atm) to pascals, multiply the atmosphere value by 101,325. For example, 1 atmosphere equals 101,325 pascals, and 2 atmospheres equals 202,650 pascals. One atmosphere is defined as standard atmospheric pressure at sea level.