IPIP — International Personality Item Pool
The single best hub for free, public-domain measurement: 3,000+ items and 250+ scales covering almost any personality construct. Explicitly public domain, so you can use, edit, or embed without asking.
Annotated resource collections
The Library
Two kinds of collection live here. The larger one annotates tools for understanding yourself, covering personality, values, moral psychology, and mental health. The internet has no shortage of quizzes; what's scarce is a map of which instruments the evidence supports. Each entry has a real research base, and each annotation says plainly what the tool measures and where its weaknesses are. The second collection is smaller and more practical, starting with material for college students.
Collections 01–03
Tools & Assessments
Self-assessment instruments, curated on the evidence and annotated one at a time. The tiers and badges described below apply throughout these three collections.
Personality & Individual Traits
Big Five, HEXACO, dark traits, empathy, and the single-construct classics: the trait models that replicate.
12 tools annotatedValues & Moral Psychology
What you prioritize, where your moral intuitions come from, and how central morality is to who you are.
11 tools annotatedMental Health & Wellbeing
The screening instruments clinics and researchers rely on, covering mood, anxiety, sleep, stress, and more, plus a short section on cognitive performance testing.
27 tools annotatedHow to read these lists
Every entry carries an evidence tier and access badges, so you can tell at a glance whether a tool is science or folklore, and whether using it costs anything.
- Strong evidence
- Replicated factor structure, cross-cultural validation, active mainstream use in peer-reviewed research.
- Moderate evidence
- A real evidence base, but with active psychometric debate, known limitations, or replication still accumulating. The annotation names the specific concern.
- Free · scored onlineFree · items + scoring keyProprietary · paid
- Access badges distinguish tools you can take scored in the browser, free item sets you score yourself, and instruments that cost money or can only be scored through a gatekeeping organization.
Meta-resources & hubs
Where to look when you want something these collections don't cover yet.
PsyToolkit Survey Library
A large library of ready-to-run academic questionnaires with citations for each. Free for students and academics, and a useful reference for everyone else.
Open-Source Psychometrics Project
A huge, mixed-quality collection of interactive tests, with serious instruments and self-produced quizzes side by side. Read the notes on each specific test before trusting it; as a discovery tool and open-data project, it's excellent.
ClearerThinking.org
Spencer Greenberg's nonprofit builds free interactive tools and mini-courses on decision-making, habits, and self-knowledge, roughly 80 in all. The methodology is unusually transparent: literature review first, then in-house studies, plus the Transparent Replications project that audits published psychology. Most of the assessments are validated internally rather than in the peer-reviewed literature, so treat them as well-designed structured reflection rather than measurement. On those terms, they're some of the best on the internet.
YourMorals.org
The Haidt/Graham research group's public-facing site: take the Moral Foundations Questionnaire and related instruments and see how you compare with the aggregate dataset.
HealthMeasures (PROMIS)
The NIH-funded home of PROMIS: patient-reported outcome measures for emotional distress, sleep, fatigue, pain, and social function, built with modern psychometrics (item response theory) and free to use.
What you won't find here
Curation means leaving things out. These are excluded on the evidence, despite being everywhere.
MBTI. Splits continuous traits into 16 boxes, and test-retest agreement is poor: a large share of people get a different type within weeks. Anything real it captures, the Big Five measures better.
Enneagram. A rich reflective tradition with thin empirical validation: type assignment is unreliable, and the nine-type structure hasn't survived psychometric scrutiny.
DISC. Ubiquitous in workplace trainings; the peer-reviewed validity evidence outside vendor materials is remarkably thin for something so widely sold.
Learning styles (VARK and kin). The core claim, that matching instruction to your 'style' improves learning, has repeatedly failed controlled tests.
A useful rule for anything not listed: if a test only ever tells you flattering things, it's marketing. Real instruments have score distributions, known error, and at least one finding their authors wish weren't true.
Practical resources
For Students
Material that isn't an assessment and doesn't belong in the collections above. This part of the Library is new.
Student Resources
Printable planners and calendars, plus two AI prompts set up for tutoring. Aimed at college students.
Browse student resources