MetTutor Explorer — Free Metrology Education
Explorer · Free forever

Explore the science that measures everything

Curious about how the world is measured? You’re already a metrologist. MetTutor Explorer gives you real conversations with an AI tutor grounded in international metrology standards — no credit card, no time limit, no feature cliffs.

Start exploring → Compare all plans

Free forever · No credit card required

20,000+
Standards chunks
3
Interfaces
2
Built-in calculators
Free
Forever
What you get

A genuine feel for MetTutor’s capabilities

Explorer isn’t a limited trial — it’s a full AI tutor experience grounded in real standards. Ask questions, learn through structured topics, take quizzes, and run calculations with answers you can trust.

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AI tutor powered by the MetLibrary
Every response is grounded in 571 curated documents (20,000+ semantically indexed chunks) spanning measurement science, calibration systems, quality management, and uncertainty analysis. Cited in APA format so you can verify every claim.
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The Measured World — 41 topics
An entry point for anyone curious about measurement. Forty-one topics across Measurement Around You, Measurement That Changed Things, and The Basics — each lesson names actual job titles and career paths in metrology.
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Standards-grounded answers
Conversations are anchored in ISO/IEC 17025:2017 and NIST GUM (JCGM 100:2008) — the foundational standards for laboratory competence and measurement uncertainty. No hallucinations, no guesswork.
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Topic Quiz & Daily Quiz
Topic Quiz: choose a subject and practice on demand (3/day on Explorer). Daily Quiz: three curated questions from a pre-vetted bank across all five Body of Knowledge domains, every day.
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Two built-in calculators
SI Unit Converter for dimensional analysis and a simplified TUR/TAR calculator for basic test uncertainty ratio evaluation — available to every Explorer user.
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Skill Recommendations *
When your question matches a specialized skill, MetTutor suggests it — one tap to open. Combined-signal matching finds the right tool for your query automatically.
* Limited by plan
Your interfaces

Three ways to explore measurement science

Ask. Learn. Practice. Each interface is powered by the MetLibrary — 571 curated documents (20,000+ chunks) from the world’s authoritative metrology standards.

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Ask MetTutor
One conversation for everything: concepts, step-by-step calculations, standards exploration, and document analysis. Every answer grounded in the MetLibrary with APA citations.
Ask
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The Measured World
41 topics across three content areas — Measurement Around You, Measurement That Changed Things, and The Basics. A genuine introduction to measurement science, with career paths named in every lesson.
Learn
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Topic Quiz & Daily Quiz
Topic Quiz: choose a subject and practice (3/day on Explorer). Daily Quiz: three curated questions from a pre-vetted bank across all five BoK domains. Build a study habit and find your gaps.
Practice
🔓 Learning Module, unlimited Topic Quiz, the 125-question CCT mock exam, and SM-2 spaced repetition are available on the Student plan and above.
Everything included

The complete Explorer feature list

Every feature below is available on the free Explorer plan — no upgrade required, no expiration, no credit card.

✓ Ask MetTutor (571 docs, 20,000+ chunks)
✓ The Measured World (41 topics) v3.1
✓ Topic Quiz (3 questions per day)
✓ Daily Quiz (3 curated questions/day)
✓ Standards-grounded answers with APA citations
✓ ISO/IEC 17025:2017 grounded answers
✓ NIST GUM uncertainty fundamentals
✓ Skill Recommendations *
✓ SI Unit Converter
✓ TUR/TAR calculator (simplified)
✓ Mic input (speech-to-text)
✓ Read-aloud per message (TTS)
✓ Light + dark themes
✓ 7-day conversation history

* Limited by plan

When you’re ready for more

Upgrade paths from Explorer

Explorer gives you a genuine feel for MetTutor. When you need unlimited quiz, certification prep tools, professional calculators, or team management — upgrade anytime.

Next step
Student
The complete learning engine for certification candidates and early-career technicians.
  • + Learning Module
  • + Unlimited Topic Quiz
  • + CCT mock exam (125 questions)
  • + SM-2 spaced repetition & goal-paced review
  • + Type B Uncertainty Estimator
  • + GUM Uncertainty Budget Calculator
  • + Export Format Toggle (DOCX/XLSX/PDF)
  • + Mastery badges & Study Achievement Record
See Student details →
Full platform
Professional
Everything in Student plus advanced professional tools, My Library workspace, and advanced standards guidance.
  • + Advanced TUR Calculator
  • + Welch-Satterthwaite Effective DOF
  • + Gage R&R (ANOVA → CMC)
  • + Decision rules & guard banding
  • + Calibration Procedure Creator & Validator
  • + My Library (saved conversations, documents, artifacts)
  • + Advanced standards guidance
See Professional details →
FAQ

Frequently asked questions

There’s no catch. Explorer is free forever — no credit card, no trial period, no expiration. You get a full AI tutor experience powered by the MetLibrary, The Measured World (41 structured learning topics), Topic Quiz and Daily Quiz, and two built-in calculators. The only limitation compared to paid plans is that advanced tools like the GUM Uncertainty Budget, unlimited quiz, spaced repetition, and the full mock exam require a Student or Professional subscription.
Explorer’s AI tutor is grounded in the core MetLibrary and provides guidance covering ISO/IEC 17025:2017, NIST GUM (JCGM 100:2008), NIST TN 1297, ASQ CCT Body of Knowledge, and VIM (JCGM 200:2012). Advanced standards guidance — covering NCSLI Recommended Practices, ANSI/NCSL Z540.3, A2LA reference guides, and JCGM 106 decision rules — is available on Professional plans and above.
Yes. You can upgrade to Student or Professional at any time from your Account page, and upgrades take effect immediately. Your Explorer account and conversation history carry forward to the upgraded plan.
There are two quiz interfaces. Topic Quiz lets you choose a subject, refine to a focus area, and set your question count (1–5) — Explorer gets 3 per day, Student gets unlimited. Daily Quiz delivers three curated questions from a pre-vetted bank across all five BoK domains every day, on all plans. Student and Professional also unlock the full 125-question CCT mock exam and SM-2 spaced repetition.
The Export Format Toggle (Word, Excel, PDF) is available starting with the Student plan. The full workspace — My Library with saved conversations, documents, artifacts, Context Panel, and document upload — are Professional-tier features. Explorer focuses on learning through conversation, The Measured World topics, quiz practice, and built-in calculators.

Start exploring metrology today

No credit card. No time limit. Just open MetTutor and start asking questions about measurement science.

Start free → Compare all plans

© 2026 AI Metrologist, LLC · MetTutor v3.1

NCSL International (NCSLI), the American Association for Laboratory Accreditation (A2LA), the American Society for Quality (ASQ), the American National Standards Institute (ANSI), the International Organization for Standardization (ISO), the International Electrotechnical Commission (IEC), the Joint Committee for Guides in Metrology (JCGM), the National Institute of Standards and Technology (NIST), and all other organization names, product names, and trademarks referenced on this page are the property of their respective owners. MetTutor is not affiliated with, endorsed by, or sponsored by any of these organizations.