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TINV Function
Summary
The TINV function calculates the two-tailed inverse of the Student's t-distribution, returning the critical t-value for a given probability and degrees of freedom. This legacy function is essential for statistical hypothesis testing but Microsoft recommends using the more precise T.INV.2T function in modern Excel versions.
Syntax
TINV(probability, deg_freedom)Parameters
| Parameter | Type | Required | Description |
|---|---|---|---|
| probability | Number |
Yes | The probability associated with the two-tailed region of the t-distribution (0 < probability ≤ 1) |
| deg_freedom | Number |
Yes | The number of degrees of freedom (≥ 1). Non-integers are truncated |
Using the TINV Function
TINV is used in statistical analysis to find critical t-values for hypothesis testing. It returns the t-value where the probability of observing a more extreme value in either tail equals the specified probability. Ideal for two-tailed t-tests in quality control, A/B testing, and experimental research.
Common TINV Examples
Two-Tailed T-Test (5% significance)
=TINV(0.05, 60)Returns 2.000 approximately - the critical t-value for 5% two-tailed test with 60 degrees of freedom.
Convert to One-Tailed Test
=TINV(2*0.05, 10)Returns 1.812 - converts two-tailed 5% probability to one-tailed by doubling the probability.
Quality Control Example
=TINV(0.10, A1)Uses cell A1 containing degrees of freedom to find 10% two-tailed critical value.
Frequently Asked Questions
Common Errors and Solutions
#VALUE!
Cause: Non-numeric input for probability or degrees of freedom
Solution: Ensure both arguments contain valid numbers
#NUM!
Cause: Probability ≤ 0, > 1, or degrees of freedom < 1
Solution: Use probability between 0 and 1, degrees of freedom ≥ 1
#N/A
Cause: Iterative algorithm failed to converge after 100 iterations
Solution: Check input values and use T.INV.2T alternative
Notes
- TINV finds t where P(|X| > t) = probability for t-distributed X
- If deg_freedom is non-integer, Excel truncates to integer
- Precision depends on internal TDIST function accuracy
- For one-tailed tests, use TINV(2*probability, deg_freedom)
- Microsoft strongly recommends T.INV.2T for new work
Compatibility
Available in: Excel 2007+, Excel 2010, Excel 2013, Excel 2016, Excel 2019, Excel 2021, Microsoft 365
Not available in: Excel 2003 and earlier
Content last reviewed: December 9, 2025
Update frequency: As needed
Excel versions tested: Excel 2007+, Excel 2010, Excel 2013, Excel 2016