t P-Value from T-Score Calculator

Convert a t statistic and degrees of freedom into a one-sided or two-sided p-value.

📊 Statistics📐 Formula included🧠 Practice questions✓ Free

T statistic

Degrees of freedom

P-value type

Please enter valid values.

Formula and Explanation

Convert a t statistic and degrees of freedom into a one-sided or two-sided p-value.

Concept	Formula or rule
P-Value from T-Score Calculator	p is calculated from the Student t distribution with the selected df

How to Use This Calculator

Enter the sample, counts, probabilities, or summary statistics requested above.
Keep paired lists in the same order and separate values with commas.
Select the correct test direction or sample/population option when available.
Press Calculate and interpret the result together with the supporting statistics.

Worked Example

Example: For t=2.1 with df=24, the two-sided p-value is a little below 0.05.

✓ Use the exact t distribution rather than the normal approximation.

Where This Is Used

School & coursework

Check homework, understand formulas, and verify step-by-step statistics exercises.

Research

Explore estimates, uncertainty, distributions, and relationships before using full statistical software.

Business & data analysis

Summarize variation, compare groups, and communicate data-driven findings clearly.

Common Mistakes to Avoid

⚠️

Using z tables for small df
T tails are heavier.

⚠️

Entering sample size as df automatically
Degrees of freedom depend on the test.

⚠️

Ignoring the sign for one-sided tests
The direction matters.

Practice Questions

1. As df→∞, t approaches which distribution?

Answer: Standard normal.

2. For t=0, what is two-sided p?

Answer: 1

3. Do smaller df have heavier tails?

Answer: Yes.

Frequently Asked Questions

What happens as df grows?▾

The t distribution approaches the standard normal.

Why are t tails heavier?▾

They account for uncertainty in estimating σ.

Can df be non-integer?▾

Yes in Welch’s t-test, though this page accepts numeric df.