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Physical Constants Reference Table

Search and filter fundamental physical constants by name, symbol, or unit. Displays CODATA 2018 recommended values with full SI units across universal, electromagnetic, atomic, and other categories.
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Luis GonzalezCreated by Luis GonzalezLast updated:

How to Use This Calculator

  1. 1

    Use the Search Bar

    Type in a keyword like 'light', 'Planck', 'gravitational', 'electron', or 'Boltzmann' to filter the table.

  2. 2

    Select a Category

    Choose a specific category like 'Universal Constants' or 'Electromagnetic' to narrow down the displayed constants.

  3. 3

    Review Constant Details

    The table dynamically updates, showing the constant's name, symbol, CODATA 2018 value, and SI unit.

  4. 4

    Explore Significance

    Each entry provides essential information, allowing for quick reference and understanding of its physical importance.

Example Calculation

A student needs to quickly find the CODATA 2018 value for the speed of light for a physics problem.

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light

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Speed of Light

Tips

Verify CODATA Year

Always note the CODATA year (e.g., CODATA 2018) for the constants. Precision measurements are continually refined, and values may be updated in future revisions, impacting high-precision calculations.

Understand SI Units

Familiarize yourself with the SI units for each constant. Using consistent units in your calculations is paramount to avoid errors, especially in complex physics problems.

Cross-Reference for Clarity

For critical applications, cross-reference values from this tool with official CODATA publications or reputable scientific databases to ensure the most up-to-date and accurate information.

The Physical Constants Reference Table serves as an essential resource for scientists, engineers, and students, providing quick access to the most accurate CODATA 2018 values for fundamental physical constants. From the speed of light to Planck's constant, these immutable numbers underpin our understanding of the universe, from the smallest subatomic particles to the largest galaxies. Without precise values for constants like the gravitational constant (G ≈ 6.674 × 10^-11 N·m²/kg²), accurate calculations in fields like astrophysics or quantum mechanics would be impossible.

The Significance of Fundamental Physical Constants

Fundamental physical constants are the unchanging bedrock upon which the laws of nature are built. They are not arbitrary numbers but represent the intrinsic properties of the universe, dictating how forces behave, how matter interacts, and how energy is quantified. For example, the speed of light (c) defines the universal speed limit and the relationship between mass and energy, while Planck's constant (h) quantifies the discrete packets (quanta) of energy in quantum mechanics. Their precise values are crucial for everything from designing particle accelerators to calibrating global positioning systems, ensuring consistency and accuracy across scientific disciplines.

💡 One of the most famous equations, E=mc², directly utilizes the speed of light – a key physical constant. Explore its implications with our Einstein Mass-Energy Calculator.

Exploring the CODATA 2018 Standard

The CODATA (Committee on Data for Science and Technology) 2018 adjustment of the fundamental physical constants represents the most recent internationally recommended values, crucial for scientific precision. This comprehensive evaluation process, conducted every four years, incorporates the latest experimental measurements and theoretical insights to refine the values. For example, the speed of light (c) is exactly defined as 299,792,458 meters per second, while the gravitational constant (G) remains an experimentally determined value with a standard uncertainty. These standardized values ensure that scientific research and technological applications worldwide are based on a consistent and highly accurate metrological foundation.

💡 Physical constants are often integral to understanding system performance. Our Efficiency Calculator (Physics) can help you quantify how effectively energy or work is converted, often relying on these fundamental values.

The Role of Universal Constants in Physics

Universal constants, such as the speed of light (c), the gravitational constant (G), and Planck's constant (h), are integral to various physical laws, from classical mechanics to quantum theory. Their precise values are critical for modern technology and scientific research. For example, GPS systems rely on the exact speed of light and relativistic effects, while particle accelerators are designed based on the fundamental constants governing particle interactions. The ongoing effort to measure and define these constants with ever-increasing precision, as documented by CODATA, highlights their foundational importance in unifying different branches of physics and enabling technological advancements in 2025.

Evolution of Defining Physical Constants

The definition and measurement of physical constants have a fascinating history, evolving from early estimations to today's highly precise, often defined, values. Historically, constants like the speed of light were experimentally measured with increasing accuracy. However, in 2019, a significant shift occurred with the redefinition of four SI base units (kilogram, ampere, kelvin, and mole) based on fixed numerical values of fundamental constants. For instance, the speed of light (c) is now an exact defined value, used to define the meter. This means that instead of measuring the speed of light, we define it, and then measure the meter based on that definition, thereby reducing measurement uncertainty and providing a more stable foundation for metrology. This transition from measured to defined values reflects a deeper understanding of the universe's fundamental properties.

Frequently Asked Questions

What are physical constants?

Physical constants are fundamental quantities in nature that have a fixed numerical value, independent of time, space, or experimental conditions. They form the bedrock of our understanding of the universe, appearing in fundamental equations across physics, chemistry, and other sciences.

Why are physical constants important?

Physical constants are important because they define the fundamental properties and interactions within the universe, enabling us to model, predict, and understand natural phenomena. They are essential for scientific research, technological development, and calibrating measurement systems, providing a universal language for science.

What is CODATA and why is it referenced?

CODATA (Committee on Data for Science and Technology) is an international organization that periodically publishes critically evaluated, internationally recommended values for fundamental physical constants. Referencing CODATA ensures that the values used are the most accurate and widely accepted scientific benchmarks available, promoting consistency in research.

How often are physical constants updated?

CODATA typically updates its recommended values for physical constants every four years. These updates reflect advancements in experimental measurement techniques and theoretical understanding, leading to increased precision or, in some cases, redefinitions of the SI base units based on these constants.