TDIST function

Returns the Percentage Points (probability) for the Student t-distribution where a numeric value (x) is a calculated value of t for which the Percentage Points are to be computed. The t-distribution is used in the hypothesis testing of small sample data sets. Use this function in place of a table of critical values for the t-distribution.



X     is the numeric value at which to evaluate the distribution.

Degrees_freedom     is an integer indicating the number of degrees of freedom.

Tails     specifies the number of distribution tails to return. If tails = 1, TDIST returns the one-tailed distribution. If tails = 2, TDIST returns the two-tailed distribution.


  • If any argument is nonnumeric, TDIST returns the #VALUE! error value.

  • If degrees_freedom < 1, TDIST returns the #NUM! error value.

  • The degrees_freedom and tails arguments are truncated to integers.

  • If tails is any value other than 1 or 2, TDIST returns the #NUM! error value.

  • TDIST is calculated as TDIST = p( x<abs(X)), where X is a random variable that follows the t-distribution.





Description (Result)




Two-tailed distribution (0.054644927 or 5.46 percent)




One-tailed distribution (0.027322463 or 2.73 percent)

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