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Two-Way ANOVA Calculator

Test the effects of two categorical factors and their interaction on one outcome. Sums of squares are Type III, matching SPSS for unbalanced designs.

Free · No sign-upReplaces SPSS GLM · PrismWorks with your data
Updated · By Bibin Xavier

Data 90 × 12

Paste from Excel, or drop a CSV, TSV or Excel file here.
Example data 90 rows, 12 variables. Data stays in this browser tab.
IDtext · 90 levelsGrouptext · 3 levelsGendertext · 2 levelsAgenumericHours_StudynumericAnxietynumericMotivationnumericPre_ScorenumericPost_ScorenumericExam_ScorenumericPassednumeric · codedSatisfactionnumeric · coded
S001ControlMale2311.2294.660626712
S002WorkshopFemale233.9283.554705402
S003OnlineFemale1810.132455576603
S004ControlMale2613.6413.552555903
S005WorkshopFemale229.7273.656636504
S006OnlineFemale207.9323.865826502
S007ControlFemale206.328372836103
S008WorkshopMale228293.164726213

Variables and options

Results update automatically when you change an option.

Results

90 rows · example data
Table 1

Tests of between-subjects effects

SourceType III SSdfMSFpPartial η²
Group1184.472592.245.38.006.114
Gender67.57167.570.61.435.007
Group × Gender647.382323.692.94.058.065
Error9240.1484110.00
Corrected total10869.2989

Note. R² = .150. Levene’s test across cells: F(5, 84) = 1.37, p = .245.

Table 2

Cell means

GroupFemale M (SD, n)Male M (SD, n)Marginal M
Control63.65 (11.89, 17)57.62 (6.89, 13)61.03
Online67.45 (8.37, 20)61.70 (11.57, 10)65.53
Workshop66.81 (10.95, 21)73.11 (13.59, 9)68.70

Interaction plot

Interpretation

The main effect of Group was statistically significant (partial η² = .114), the main effect of Gender was not statistically significant (partial η² = .007), and the interaction was not statistically significant. Non-parallel lines in the plot would suggest an interaction; here they do not differ reliably.

Group: F(2, 84) = 5.38, p = .006, η²p = .114; Gender: F(1, 84) = 0.61, p = .435, η²p = .007; interaction: F(2, 84) = 2.94, p = .058, η²p = .065.

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). Two-Way ANOVA Calculator [Web application]. FreeStatisticalTools.com. https://freestatisticaltools.com/two-way-anova-calculator/

BibTeX 

@software{xavier_twowayanova_2026,
  author = {Xavier, Bibin},
  title = {Two-Way ANOVA Calculator},
  publisher = {FreeStatisticalTools.com},
  year = {2026},
  url = {https://freestatisticaltools.com/two-way-anova-calculator/},
  note = {Web application}
}

Suggested sentence for your methods section: “The analysis was carried out with the free Two-Way ANOVA Calculator tool on FreeStatisticalTools.com (Xavier, 2026).”

What is a two-way ANOVA?

Two-way ANOVA tests the effects of two categorical factors on one outcome, and whether the factors interact. Sums of squares are Type III, so results match SPSS even when group sizes are unequal.

When to use a two-way ANOVA

Use it when two categorical factors may each affect an outcome, and you want to know whether their effects combine or interact.

Assumptions

  • Independent observations.
  • Approximately normal residuals.
  • Equal variances across cells (Levene’s test).
  • Data in every cell of the design.

How to use this tool

  1. 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.
  2. Choose the variables. Select the dependent variable, factor a and factor b.
  3. 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 a two-way ANOVA in APA style

Report each effect with F, df, p and partial η², and describe the interaction pattern with the plot.

Frequently asked questions

What is an interaction effect?

An interaction means the effect of one factor depends on the level of the other. In the interaction plot it shows as lines that are not parallel.

Why Type III sums of squares?

Type III tests each effect after adjusting for all others, which is the default in SPSS and the usual choice for unbalanced designs.

Should I interpret main effects when the interaction is significant?

Interpret them with caution. Describe the interaction first, often by looking at simple effects of one factor at each level of the other.

Related tools

One-Sample T-Test CalculatorTest whether a sample mean differs from a known or hypothesized value.Independent Samples T-Test CalculatorCompare the means of two independent groups, with Levene’s test, Welch correction and Cohen’s d.Paired Samples T-Test CalculatorCompare two related measurements, such as before and after scores from the same people.One-Way ANOVA CalculatorCompare three or more group means, with Levene’s test, Welch’s F and Tukey HSD post-hoc tests.Repeated Measures ANOVA CalculatorCompare three or more measurements from the same subjects, with Mauchly’s test and Greenhouse-Geisser correction.ANCOVA CalculatorCompare group means while controlling for covariates, with adjusted means and a homogeneity-of-slopes check.

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