Pronunciation: /ˈkɒn stənt/ ?

A constant is a value that does not change.[1] It can also be a letter that represents a value that does not change.


  1. p is used to represents the ratio of the circumference of a circle to its diameter. Since p always has the same value, it is a constant.
  2. In the expression 2 + y, the 2 is a constant value.
  3. In the linear equation y = m·x + b, both m and b represent values that do not change.

Commonly Used Constants

  • Zero, 0·a = 0, 0+a=a
  • One, 1·a = 1
  • Pi, the ratio of the length of the circumference of a circle to the diameter.
    p ˜3.14159265358979323846264338327950288
  • Euler's number, the base of the natural logarithm.
  • Phi, the golden ratio.
    f = (1+square root(5))/2 ˜ 1.61803398874989484820458683436563811
  • i, the imaginary unit.
    i = square root of -1.


  1. constant. WordNet. Princeton University. (Accessed: 2011-01-08).
  2. Kornegay, Chris. Constant, pg 72. Math Dictionary With Solutions: A Math Review, 2nd edition. Sage Publications, Inc, March 6, 1999. (Accessed: 2010-01-20).
  3. Bettinger, Alvin K. and Englund, John A.. Algebra and Trigonometry, pp 53-54. International Textbook Company, January 1963. (Accessed: 2010-01-12).

Printed Resources

Cite this article as:

Constant. 2010-01-20. All Math Words Encyclopedia. Life is a Story Problem LLC.


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Revision History

2010-01-20: Added "References" (McAdams, David.)
2010-01-05: Added "References" (McAdams, David.)
2008-11-21: Added 'More Information' (McAdams, David.)
2008-07-09: Minor edit and added vocabulary link to linear equation (McAdams, David.)
2008-02-13: Initial version (McAdams, David.)

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