π, e, φ, and 40+ mathematical and physical constants — formulas, applications, calculators, and a quiz, all in your browser.
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Can be written as a fraction of two integers, e.g. 1/2.
Cannot be written as a simple fraction; its decimal expansion never repeats.
A root of a polynomial equation with rational coefficients, e.g. √2.
Not the root of any polynomial with rational coefficients, e.g. π and e.
Pi (π) is the most well-known constant, representing the ratio of a circle's circumference to its diameter. It appears throughout geometry, physics, and statistics.
Euler's Number (e) is the base of the natural logarithm and appears in exponential growth, compound interest, calculus, and probability distributions.
Irrational numbers cannot be written as a simple fraction. Algebraic numbers are roots of a polynomial with rational coefficients (like √2). Transcendental numbers, like π and e, are not the root of any such polynomial.
Most fundamental constants are shown to 30-50 decimal digits; use the precision slider to control how many digits are displayed. Physical constants use the current internationally accepted CODATA/SI values.
No. Mathematical constants are fixed by definition. Physical constants can have their measured precision refined over time, but several (like the speed of light) are now defined as exact values.
No. Everything, including favorites and recently viewed constants, is stored only in your browser's local storage and never sent to a server.
Yes. Use the Compare Constants panel to select any two constants and see their values side by side along with their ratio.
A circle circumference/area calculator (π), a continuous compound interest calculator (e), a degree-to-radian converter (π), and a golden rectangle generator (φ).
Students, teachers, mathematicians, engineers, physicists, computer scientists, and researchers all regularly work with mathematical and physical constants.
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