T Test Calculator
Enter a sample mean, the population mean, the sample standard deviation and sample size to get the one-sample t statistic and its degrees of freedom (n minus 1).
What this calculator does
The T Test Calculator estimates your result instantly from the values you enter, using standard statistics formulas. Enter a sample mean, the population mean, the sample standard deviation and sample size to get the one-sample t statistic and its degrees of freedom (n minus 1). Calculations run in your browser, so nothing you type is sent to a server, and the output is an estimate rather than a certified or official figure.
Result
About T Test Calculator
This calculator runs a one-sample t test. Give it a sample mean, the hypothesized population mean (μ₀), the sample standard deviation and the sample size, and it returns the t statistic and the degrees of freedom (n minus 1).
Use it to check whether a sample average differs from a reference value; then compare the t statistic against the critical value for your chosen significance level.
Formula & Mathematical Calculation
t Statistic = f(Sample mean, Population mean (μ₀), Sample std. deviation, Sample size (n))
Calculated according to standard stats formulas implemented in the calculator core.
Calculation Example
Enter a Sample mean of 52, a Population mean of 50, a Sample std. deviation of 6 and a Sample size of 25, then click Calculate.
The tool returns t Statistic = 1.6667 and Degrees of Freedom = 24, with the note: “One-sample t = 1.6667 with 24 degrees of freedom. Compare with the critical t value at your significance level.”
Key Benefits
- Computes the one-sample t statistic from the sample mean, population mean, sample standard deviation and sample size
- Reports the degrees of freedom as the sample size minus one
- Reminds you in the result note to compare the t value against the critical t for your significance level
- Requires a positive standard deviation and a sample size of at least 2, warning you otherwise
How to Use this Calculator
-
Enter the sample mean
Type the average of your sample into the Sample mean field. -
Enter the population mean
Type the reference or hypothesized population mean into the Population mean field. -
Enter spread and size
Type the sample standard deviation (greater than 0) and the sample size (at least 2). -
Calculate and read
Click Calculate, then read the t Statistic box and the Degrees of Freedom box.
Assumptions & Limitations
What the calculation assumes
- Every value you enter is treated as an exact, known amount.
- Any rate or interval you enter is assumed to hold for the whole period unless the form asks for it separately.
- Results use standard published formulas and account only for the values entered above.
- Rounding is applied for display; the underlying calculation uses your full precision.
- Results are returned in the same units you enter, unless the tool states the output unit.
What it does not cover
- T Test Calculator produces a calculated result for reference and learning, not a certified or official measurement.
- Real-world outcomes differ when tolerances, rounding rules or local standards apply.
- Definitions and standards vary by region and change over time; verify the convention that applies to your case.
- Figures are only as accurate as the inputs you supply — check them before acting on the result.
- For work where the result carries real consequences, confirm it against an authoritative source.
Frequently Asked Questions
Free to use, no account needed. Calculations run in your browser, so nothing you type is sent to a server. Results are estimates — how we build and check our calculators.