t-Table (Student’s t Distribution Table)

t-Table (Student’s t Distribution Table) and find critical Values Guide

Use the Student’s t-Table Calculator below to quickly find critical t-values based on your selected degrees of freedom, confidence level, and probability region. Simply enter the required inputs to calculate the appropriate t-value and visualize the corresponding area on the t-distribution curve.

The calculator also serves as a convenient t-distribution reference table, helping students, researchers, engineers, Six Sigma practitioners, and data analysts determine critical values for confidence intervals and hypothesis testing without manually searching statistical tables.

Visual probability

Student's t Distribution

Selected regionP(-2.0639 <= T <= 2.0639)

Probability0.9500

At 24 degrees of freedom, the t distribution has slightly heavier tails than the standard normal distribution.

Calculator

Find a Critical t-Value

Degrees of freedomFor a one-sample procedure, df = n - 1.

Confidence level

Probability region

Two tailsTwo-sided confidence interval Right tailUpper-tail critical value Left tailLower-tail critical value Central areaSymmetric confidence region

Display precision

Calculated answer

Results

Critical t-value+/-2.0639Two-sided critical boundaries

Confidence level95.00%Selected probability level

Alpha0.05000.0250 in each tail

Degrees of freedom24Determines the distribution shape

What this result means

View Step-by-Step Solution

Formula

What Is a t-Statistic?

A t-statistic measures how far a sample estimate is from a hypothesized value in units of estimated standard error.

t = (x-bar - mu) / (s / sqrt(n))

x-bar = sample mean
mu = hypothesized population mean
s = sample standard deviation
n = sample size

Quick reference

Common Critical t-Values

Positive critical values for two-sided confidence intervals.

df	90%	95%	99%

Student's t reference table

Critical Values of Student's t Distribution

Use the row for degrees of freedom and the column for the required alpha.

Table type

Highlight df

For a two-tailed test, total alpha is divided equally between the two tails.

Values are rounded to three decimal places. The Infinity row shows the standard normal limiting values.

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Published: August 27, 2026
Last Updated: September 16, 2026

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