Psychology tools
What tools does PsychologyOrbit have?
26 free calculators across research methods, clinical and counselling, educational, industrial-organisational, forensic, cognitive, social, sport and health psychology, plus an SPSS data preparation tool. They run without an account and each states its assumptions alongside the result.
PsychologyOrbit tools index, 2 November 2026.
New
SPSS data preparation and analysis
Turn a Google Forms or Excel export into a ready .sav file: clean variable names, Likert answers coded as numbers, reverse-scored items, checkbox answers split into columns, every label set. Then run t tests, correlations, ANOVA, chi-square, regression or Cronbach's alpha and get the APA write-up. Runs in your browser: your data never leaves your computer.
New · Thesis helper
Sample size, power and choosing a test
How many participants your thesis needs, with the APA sentence for your method section; which analysis fits your design; and a checklist from ethics approval to submission.
New · Exam prep
Licensing exam practice
Original questions across the eight exam areas, with explanations, a timed mock and progress by area.
New · Journal club
One paper a week, read together
Propose and vote for papers; each Monday's winner gets questions and an open discussion.
Research methods and statistics
Sample size calculator
How many participants per group you need to detect an effect of a given size.
Statistical power calculator
The power a study already has, given its sample size and the effect it was looking for.
Cohen’s d calculator
Effect size from two group means and standard deviations, with its confidence interval.
Correlation confidence interval
The confidence interval around a correlation, via Fisher transformation.
Independent samples t-test
A two-group t-test from summary statistics, with the effect size alongside it.
Chi-square test of independence
A 2x2 contingency test, with the effect size and a warning about small expected counts.
Descriptive statistics
Mean, median, standard deviation and range from a pasted column of numbers.
Cronbach’s alpha
Internal consistency of a scale from item scores, with alpha if each item were deleted and corrected item-total correlations.
Cohen’s kappa (inter-rater agreement)
Agreement between two raters beyond chance, for coded interviews, observations or diagnoses.
Effect size converter
Convert between Cohen's d, r, the odds ratio and eta squared for two groups.
One-way ANOVA from means and SDs
F test for three or more groups from published summary statistics, with eta and omega squared.
APA 7 reference builder
A correctly formatted APA 7th edition reference, with its in-text citation, for an article, book, chapter or web page.
APA results writer
Turn a test result into an APA-style sentence with the statistic, degrees of freedom, exact p and effect size.
Clinical and counselling
Reliable change index
Did a client really change between two assessments, or is the difference within measurement error? Jacobson and Truax (1991).
Standard score converter
Convert between z, T, standard (IQ-metric), scaled and percentile scores, with the stanine.
Educational and developmental
Age calculator for testing
Exact age in years, months and days on the test date, as test manuals ask for it, with age corrected for prematurity.
Readability checker
Flesch Reading Ease and Flesch-Kincaid grade level for an information sheet, consent form or questionnaire.
Item analysis for a test
Difficulty, discrimination and point-biserial correlation for each item of a right/wrong test, with KR-20 reliability.
Industrial and organisational
Adverse impact (four-fifths rule)
Selection rates by group and the impact ratio against the highest-rate group, with a significance test.
Content validity ratio (Lawshe)
Which items a panel of experts rated essential often enough to keep, with the exact critical value for your panel size.
Forensic
Cognitive and experimental
Social
Sport and exercise
Heart-rate training zones (Karvonen)
Target heart rates from heart-rate reserve, for exercise prescription and sport-psychology interventions.
Training load, monotony and strain
Session-RPE load per week, with Foster's monotony and strain, from each day's effort rating and minutes.
Health
Something missing?
ANOVA, reliability coefficients, regression helpers and a questionnaire builder are on the list. Tell us which you would actually use and it moves up.