T Test Calculator
One-sample and two-sample t statistics.
Enter your values
Enter the sample 1 values you are working with.
Enter the sample 2 values (optional) you are working with.
Enter the hypothesised mean (one sample) you are working with.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- t statistic
- -4.40542
- Mean difference
- -4.1429
- Standard error
- 0.9404
- Mean 1
- 13.2857
- Mean 2
- 17.4286
- Approx. df
- 6
Quick answer
A t test measures how many standard errors separate means, telling you whether a difference is likely real.
t = (x̄ − μ) / (s/√n)
At a glance
| What it does | One-sample and two-sample t statistics. |
|---|---|
| Category | Statistics |
| Inputs needed | Sample 1 values, Sample 2 values (optional), Hypothesised mean (one sample) |
| Main output | t statistic |
| Formula | t = (x̄ − μ) / (s/√n) |
| Cost | Free — no sign-up, no download |
How to use the T Test Calculator
- 1Paste sample 1 values.
- 2Add sample 2 for a two-sample test, or leave blank.
- 3Enter the hypothesised mean for a one-sample test.
Inputs explained
- Sample 1 values
- Enter the sample 1 values you are working with.
- Sample 2 values (optional)
- Enter the sample 2 values (optional) you are working with.
- Hypothesised mean (one sample)
- Enter the hypothesised mean (one sample) you are working with.
Worked example
Using the values the calculator loads with:
Inputs
- Sample 1 values12, 14, 11, 15, 13, 16, 12
- Sample 2 values (optional)17, 15, 19, 16, 18, 20, 17
- Hypothesised mean (one sample)13
Results
- t statistic-4.40542
- Mean difference-4.1429
- Standard error0.9404
- Mean 113.2857
- Mean 217.4286
- Approx. df6
Frequently asked questions
When do I use a t test instead of z?
When the population standard deviation is unknown and the sample is small.
What t value is significant?
Roughly 2.0 for 30 observations at the 5% level — check a t table for exact df.
What do I need to enter into the T Test Calculator?
Just 3 values: sample 1 values, sample 2 values (optional), hypothesised mean (one sample). Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the T Test Calculator work out the answer?
A t test measures how many standard errors separate means, telling you whether a difference is likely real. It applies the formula t = (x̄ − μ) / (s/√n) and shows the working so you can check each step by hand.
Is the T Test Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.