What is the Universal Numbering System?

The Universal Numbering System (ADA system) numbers permanent teeth 1 through 32, starting from the upper-right third molar (#1) and going clockwise to the lower-right third molar (#32). It is the standard in the United States.

What is the ISO/FDI system?

The FDI World Dental Federation system uses two digits. The first digit represents the quadrant (1=upper-right, 2=upper-left, 3=lower-left, 4=lower-right for permanent teeth), and the second digit represents the tooth position (1=central incisor to 8=third molar). It is used internationally.

What is Palmer notation?

Palmer notation uses the numbers 1–8 combined with a bracket symbol indicating the quadrant (upper-right, upper-left, lower-left, lower-right). Because the bracket symbol is hard to type, this tool represents it as UR1, UL1, LL1, LR1 (quadrant + number).

Does this tool cover primary (baby) teeth?

Yes. Select Primary to convert Universal letters A–T, FDI codes 51–55, 61–65, 71–75 and 81–85, or text-safe Palmer quadrant codes using A–E.

Are wisdom teeth included?

Yes. Wisdom teeth are tooth #1, #16, #17, and #32 in Universal numbering; 18, 28, 38, 48 in FDI; and UR8, UL8, LL8, LR8 in Palmer.

Tooth Numbering Converter

Choose permanent or primary dentition, then enter a Universal, ISO/FDI, or text-safe Palmer identifier to see the same tooth in all three systems.

Convert a Tooth Number

Dentition

Input System

Universal ID (1–32)

Full Permanent Teeth Chart

Directions are from the patient's perspective. Click any tooth to convert it. Shaded = selected.

Upper Right Upper Left

Lower Right Lower Left

I = Incisor

C = Canine

P = Premolar

M = Molar

Quick Reference — All 32 Permanent Teeth

Universal	FDI	Palmer	Name

Reference scope: ISO 3950 defines the two-digit designation system; the ADA Universal system uses 1–32 for permanent teeth and A–T for primary teeth. Palmer results use text-safe aliases such as UR1 or URE because quadrant glyphs can be lost in plain text. Verify the notation shown in the original clinical record before treatment or billing.

ISO 3950 ADA dental terms

Summary

The Tooth Numbering Converter lets you translate any tooth identifier between the three major dental notation systems used worldwide. Universal numbering (1–32) is standard in the US, ISO/FDI two-digit notation is used internationally, and Palmer notation uses a quadrant symbol with a number. Understanding all three is essential for reading international dental records, patient charts, and academic literature.

How it works

Select the notation system you are starting from (Universal, ISO/FDI, or Palmer).
Enter the tooth number or click a tooth on the interactive dental chart.
The converter instantly shows the equivalent in all three systems.
Hover over any result to see the full anatomical name and quadrant.
Use the full chart view to look up all 32 permanent teeth or all 20 primary teeth.

Use cases

Translate tooth numbers from US patient records to international ISO/FDI format.
Help dental students learn all three major numbering systems side by side.
Cross-reference treatment plans received from overseas dental offices.
Verify tooth identification when reviewing X-ray reports or referral letters.
Quick lookup during continuing education courses that use unfamiliar notation.
Prepare billing codes that require Universal numbering from FDI source data.

Frequently Asked Questions

Last updated: 2026-09-30 · Reviewed by Nham Vu