🔄 Converters & References

Tooth Numbering System Converter

Click any tooth on the interactive dental chart to instantly see the equivalent code in Universal (1-32), FDI/ISO Two-Digit, and Palmer notation. Covers all 32 permanent and 20 primary teeth.

Universal (1-32) FDI / ISO Palmer Notation Primary Teeth Interactive Chart
Tooth Numbering System Converter
Click any tooth to see all three notation systems
Patient's Right →     ← Patient's Left
Select a tooth to see numbering conversions
Full Permanent Teeth Reference Table
UniversalFDI / ISOPalmerTooth NameLocation

The three tooth numbering systems explained

Three distinct tooth numbering systems are in active clinical use worldwide. Understanding all three is essential for anyone working with international referrals, published research, or software that may default to different conventions.

Universal Numbering System is used in the United States. Numbers run 1-32 for permanent teeth, starting at the upper right third molar (1) and finishing at the lower right third molar (32). Primary teeth use letters A-T. Simple to learn, though the numbering wraps around the mouth in a way that isn't immediately intuitive.

FDI/ISO Two-Digit System is used internationally and is the official system of the World Dental Federation. The first digit identifies the quadrant (1=upper right, 2=upper left, 3=lower left, 4=lower right for permanent teeth; 5-8 for primary teeth). The second digit identifies position from the midline. Tooth 16 is the upper right first molar (Universal 3). This system is logical and extensible.

Palmer Notation is used predominantly in the United Kingdom and parts of Europe. It uses a grid symbol (⌐ ¬ L Γ for the four quadrants) combined with a number 1-8 from the midline. Concise but requires special symbols that don't always render correctly in digital systems.

For clinical documentation requiring tooth identification, also see our CDT Code Lookup Tool which documents all procedures by tooth number. For fee scheduling purposes, the Fee Schedule Estimator uses CDT codes which require correct tooth identification.

Frequently Asked Questions

Universal numbering (1-32) is used primarily in the United States. Teeth are numbered sequentially starting at the upper right third molar (1) across the top to the upper left third molar (16), then dropping to the lower left third molar (17) and across to the lower right third molar (32). FDI Two-Digit notation is used internationally. The first digit identifies the quadrant (1=upper right, 2=upper left, 3=lower left, 4=lower right) and the second identifies the tooth from the midline. Universal tooth 3 (upper right first molar) is FDI 16.
Referrals from the UK and most of Europe will use FDI or Palmer notation, not the Universal system. A referral describing work on "tooth 26" means the upper left first molar (FDI) - which is Universal tooth 14. Without knowing this, a US clinician reading "tooth 26" might think the lower left first molar (Universal 26) is involved - a different tooth entirely on the opposite arch. Always identify the notation system being used before acting on a referral letter.

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