Independent Samples T-Test Calculator
Compare two independent groups on a continuous outcome. You get Student’s and Welch’s tests side by side, Levene’s test to choose between them, and effect sizes.
Updated · By Bibin XavierData 90 × 12
| IDtext · 90 levels | Grouptext · 3 levels | Gendertext · 2 levels | Agenumeric | Hours_Studynumeric | Anxietynumeric | Motivationnumeric | Pre_Scorenumeric | Post_Scorenumeric | Exam_Scorenumeric | Passednumeric · coded | Satisfactionnumeric · coded |
|---|---|---|---|---|---|---|---|---|---|---|---|
| S001 | Control | Male | 23 | 11.2 | 29 | 4.6 | 60 | 62 | 67 | 1 | 2 |
| S002 | Workshop | Female | 23 | 3.9 | 28 | 3.5 | 54 | 70 | 54 | 0 | 2 |
| S003 | Online | Female | 18 | 10.1 | 32 | 4 | 55 | 57 | 66 | 0 | 3 |
| S004 | Control | Male | 26 | 13.6 | 41 | 3.5 | 52 | 55 | 59 | 0 | 3 |
| S005 | Workshop | Female | 22 | 9.7 | 27 | 3.6 | 56 | 63 | 65 | 0 | 4 |
| S006 | Online | Female | 20 | 7.9 | 32 | 3.8 | 65 | 82 | 65 | 0 | 2 |
| S007 | Control | Female | 20 | 6.3 | 28 | 3 | 72 | 83 | 61 | 0 | 3 |
| S008 | Workshop | Male | 22 | 8 | 29 | 3.1 | 64 | 72 | 62 | 1 | 3 |
Variables and options
Results
90 rows · example dataGroup statistics
| Group | n | M | SD | SE | 95% CI |
|---|---|---|---|---|---|
| Female | 58 | 66.10 | 10.38 | 1.36 | [63.37, 68.83] |
| Male | 32 | 63.25 | 12.13 | 2.14 | [58.88, 67.62] |
Independent samples t-test
| Levene’s F | p | t | df | p | Mean difference | SE | 95% CI | |
|---|---|---|---|---|---|---|---|---|
| Equal variances assumed (Student) | 0.95 | .331 | 1.18 | 88 | .243 | 2.85 | 2.43 | [-1.97, 7.68] |
| Equal variances not assumed (Welch) | 1.12 | 56.11 | .266 | 2.85 | 2.54 | [-2.24, 7.94] |
Note. Levene’s test is not significant, so either row is acceptable; many journals now recommend Welch by default. Effect sizes: Cohen’s d = 0.26, Hedges’ g = 0.26.
Group means with 95% CI
Interpretation
Female (M = 66.10) and Male (M = 63.25) did not differ significantly on Post_Score. The difference of 2.85 points is a small effect.
How to cite this tool
Using these results in a thesis, journal article, report or class assignment? Please cite this free tool so others can find it. It keeps the site free.
APA 7
Xavier, B. (2026). Independent Samples T-Test Calculator [Web application]. FreeStatisticalTools.com. https://freestatisticaltools.com/independent-t-test-calculator/
BibTeX
@software{xavier_independentttest_2026,
author = {Xavier, Bibin},
title = {Independent Samples T-Test Calculator},
publisher = {FreeStatisticalTools.com},
year = {2026},
url = {https://freestatisticaltools.com/independent-t-test-calculator/},
note = {Web application}
}Suggested sentence for your methods section: “The analysis was carried out with the free Independent Samples T-Test Calculator tool on FreeStatisticalTools.com (Xavier, 2026).”
What is an independent samples t-test?
The independent samples t-test compares the means of two unrelated groups, such as a treatment and a control group. This calculator shows Student’s and Welch’s versions side by side, with Levene’s test for equal variances and standardized effect sizes.
When to use an independent samples t-test
Use it when one continuous outcome is measured in two separate groups, such as treatment and control.
Assumptions
- Independent observations in two unrelated groups.
- An approximately normal outcome in each group, or around 30+ per group.
- Equal variances for Student’s version. Welch’s version does not need this.
How to set up your data
Long format: one column for the outcome and one for the group label. If the grouping variable has more than two levels, choose the two to compare.
How to use this tool
- Enter your data. Paste columns from Excel, Google Sheets or SPSS with variable names in the first row, or upload a CSV or Excel file. The example data shows the expected layout.
- Choose the variables. Select the dependent variable, grouping variable, group 1 and group 2.
- Read the results. Results update automatically. Read the plain-English interpretation, then use Copy table to paste APA-style tables into Word and Copy for the results sentence.
How to report an independent samples t-test in APA style
“Women (M = 66.1, SD = 10.2) scored higher than men (M = 61.8, SD = 11.0), t(88) = 1.92, p = .058, d = 0.41.”
Frequently asked questions
Should I report Student’s or Welch’s t-test?
Welch’s test does not assume equal variances and loses almost nothing when variances are equal, so many methodologists recommend reporting it by default. If Levene’s test is significant, Welch’s test is required.
How do I interpret Cohen’s d?
By Cohen’s conventions, d = 0.2 is small, 0.5 medium and 0.8 large. Hedges’ g applies a small-sample correction and is preferred when groups are small.
How should my data be arranged?
Use long format: one column with the outcome scores and one column with the group label. If the group column has more than two categories, choose the two you want to compare.
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