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). Primary teeth use the letters A to T in the same order. It is the standard in the United States.

What is the ISO/FDI system?

The FDI World Dental Federation system, adopted as ISO 3950, uses two digits. The first digit is the quadrant (1 = upper right, 2 = upper left, 3 = lower left, 4 = lower right for permanent teeth; 5 to 8 for primary teeth) and the second is the position from the midline (1 = central incisor to 8 = third molar). It is read “two-six”, not “twenty-six”.

Why does tooth number 14 mean two different teeth?

Because the systems overlap. Universal #14 is the upper left first molar, which is 26 in FDI. FDI 14 is the upper right first premolar, which is Universal #5. Any number from 11 to 32 can be read either way, so always confirm which system a chart or letter uses before treatment.

What is Palmer notation?

Palmer (Zsigmondy–Palmer) notation writes the tooth number 1 to 8, or A to E for baby teeth, inside a right-angle bracket that marks the quadrant as seen when facing the patient: 6⏌ is the upper right first molar, ⎿6 the upper left, 6⏋ the lower right and ⎾6 the lower left. Because the brackets are often lost in plain text, this tool also gives the text-safe codes UR6, UL6, LR6 and LL6.

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 Palmer A–E. The result also names the permanent successor, for example primary tooth A (FDI 55) is replaced by the upper right second premolar, Universal #4 (FDI 15).

Are wisdom teeth included?

Yes. Wisdom teeth are tooth #1, #16, #17, and #32 in Universal numbering; 18, 28, 38, 48 in FDI; and 8⏌, ⎿8, ⎾8, 8⏋ (UR8, UL8, LL8, LR8) in Palmer.

What is the difference between FDI and Universal tooth numbering?

Universal counts the 32 adult teeth in one run: 1 to 16 across the upper arch from the right third molar, then 17 to 32 back along the lower arch. FDI splits the mouth into four quadrants, so the second digit always names the tooth type. The upper right first molar is 3 in Universal and 16 in FDI. Baby teeth use letters A to T in Universal and 51 to 85 in FDI.

Which tooth is number 30?

In Universal numbering, #30 is the lower right first molar, FDI 46 and Palmer 6⏋ (LR6). It is one of the most commonly restored teeth. Number 19 is its mirror image on the lower left (FDI 36), and numbers 3 and 14 are the upper first molars (FDI 16 and 26).

Why does Palmer notation run 8 to 1 and then 1 to 8?

Palmer numbers each quadrant from the midline outward, 1 for the central incisor to 8 for the third molar. Reading the upper arch from the patient's right to left gives 8 7 6 5 4 3 2 1, then 1 2 3 4 5 6 7 8 on the left side. The bracket shape, or UR and UL in this tool, shows which side each tooth is on.

Tooth Numbering Converter

Enter a Universal, ISO/FDI or Palmer tooth number, or paste a list, to see the same teeth in all three systems with names, Palmer symbols and baby-tooth successors.

Universal numbers adult teeth 1 to 32, from the upper right third molar around to the lower right third molar.

Convert a Tooth Number

Dentition

Input System

Universal ID (1–32)

Convert a List of Teeth

Paste teeth separated by commas, spaces or new lines. Adult and baby teeth can be mixed.

The list uses Teeth

Input	Universal	FDI	Palmer	Name

Full Permanent Teeth Chart

Directions are from the patient's perspective (the chart is drawn as you face the patient). Click any tooth to convert it. Shaded = selected.

Upper RightUpper Left

Lower RightLower Left

I = Incisor

C = Canine

P = Premolar

M = Molar

Tooth Numbering Chart — All 32 Permanent Teeth

Universal	FDI / ISO	Palmer	Name
1	18	8⏌ (UR8)	Upper Right Third Molar (Wisdom)
2	17	7⏌ (UR7)	Upper Right Second Molar
3	16	6⏌ (UR6)	Upper Right First Molar
4	15	5⏌ (UR5)	Upper Right Second Premolar
5	14	4⏌ (UR4)	Upper Right First Premolar
6	13	3⏌ (UR3)	Upper Right Canine
7	12	2⏌ (UR2)	Upper Right Lateral Incisor
8	11	1⏌ (UR1)	Upper Right Central Incisor
9	21	⎿1 (UL1)	Upper Left Central Incisor
10	22	⎿2 (UL2)	Upper Left Lateral Incisor
11	23	⎿3 (UL3)	Upper Left Canine
12	24	⎿4 (UL4)	Upper Left First Premolar
13	25	⎿5 (UL5)	Upper Left Second Premolar
14	26	⎿6 (UL6)	Upper Left First Molar
15	27	⎿7 (UL7)	Upper Left Second Molar
16	28	⎿8 (UL8)	Upper Left Third Molar (Wisdom)
17	38	⎾8 (LL8)	Lower Left Third Molar (Wisdom)
18	37	⎾7 (LL7)	Lower Left Second Molar
19	36	⎾6 (LL6)	Lower Left First Molar
20	35	⎾5 (LL5)	Lower Left Second Premolar
21	34	⎾4 (LL4)	Lower Left First Premolar
22	33	⎾3 (LL3)	Lower Left Canine
23	32	⎾2 (LL2)	Lower Left Lateral Incisor
24	31	⎾1 (LL1)	Lower Left Central Incisor
25	41	1⏋ (LR1)	Lower Right Central Incisor
26	42	2⏋ (LR2)	Lower Right Lateral Incisor
27	43	3⏋ (LR3)	Lower Right Canine
28	44	4⏋ (LR4)	Lower Right First Premolar
29	45	5⏋ (LR5)	Lower Right Second Premolar
30	46	6⏋ (LR6)	Lower Right First Molar
31	47	7⏋ (LR7)	Lower Right Second Molar
32	48	8⏋ (LR8)	Lower Right Third Molar (Wisdom)

Baby Tooth Chart — All 20 Primary Teeth

Universal	FDI / ISO	Palmer	Name	Replaced by (Universal / FDI)
A	55	E⏌ (URE)	Upper Right Primary Second Molar	#4 / 15
B	54	D⏌ (URD)	Upper Right Primary First Molar	#5 / 14
C	53	C⏌ (URC)	Upper Right Primary Canine	#6 / 13
D	52	B⏌ (URB)	Upper Right Primary Lateral Incisor	#7 / 12
E	51	A⏌ (URA)	Upper Right Primary Central Incisor	#8 / 11
F	61	⎿A (ULA)	Upper Left Primary Central Incisor	#9 / 21
G	62	⎿B (ULB)	Upper Left Primary Lateral Incisor	#10 / 22
H	63	⎿C (ULC)	Upper Left Primary Canine	#11 / 23
I	64	⎿D (ULD)	Upper Left Primary First Molar	#12 / 24
J	65	⎿E (ULE)	Upper Left Primary Second Molar	#13 / 25
K	75	⎾E (LLE)	Lower Left Primary Second Molar	#20 / 35
L	74	⎾D (LLD)	Lower Left Primary First Molar	#21 / 34
M	73	⎾C (LLC)	Lower Left Primary Canine	#22 / 33
N	72	⎾B (LLB)	Lower Left Primary Lateral Incisor	#23 / 32
O	71	⎾A (LLA)	Lower Left Primary Central Incisor	#24 / 31
P	81	A⏋ (LRA)	Lower Right Primary Central Incisor	#25 / 41
Q	82	B⏋ (LRB)	Lower Right Primary Lateral Incisor	#26 / 42
R	83	C⏋ (LRC)	Lower Right Primary Canine	#27 / 43
S	84	D⏋ (LRD)	Lower Right Primary First Molar	#28 / 44
T	85	E⏋ (LRE)	Lower Right Primary Second Molar	#29 / 45

Reference scope: ISO 3950 (the FDI two-digit system) designates teeth by quadrant and position; the ADA Universal system uses 1–32 for permanent teeth and A–T for primary teeth; Palmer symbols are the Unicode dentistry characters ⏌ ⎿ ⏋ ⎾ (U+23CC, U+23BF, U+23CB, U+23BE). Successors pair each baby tooth with the permanent tooth in the same quadrant position: primary molars are replaced by premolars, while permanent molars erupt behind the baby teeth. Verify the notation used in the original clinical record before treatment or billing.

ISO 3950 ADA dental terms Unicode Miscellaneous Technical (dentistry symbols)

Quick answer

Universal numbers adult teeth 1 to 32, from the upper right third molar around to the lower right third molar. ISO/FDI uses two digits, quadrant (1 to 4) then tooth (1 to 8), and Palmer gives the tooth 1 to 8 inside a quadrant bracket, such as 6⏌ for the upper right first molar.

Examples

Universal	ISO/FDI	Palmer
1	18	8⏌ (UR8)
8	11	1⏌ (UR1)
9	21	⎿1 (UL1)
14	26	⎿6 (UL6)
19	36	⎾6 (LL6)
30	46	6⏋ (LR6)

Type a number in any system, paste a list, or click a tooth on the chart to see all three notations and the tooth name.

Summary

The Tooth Numbering Converter translates tooth identifiers between the three major dental notation systems. Universal numbering (1–32 for adult teeth, A–T for baby teeth) is standard in the US, the ISO 3950 / FDI two-digit system is used internationally, and Palmer notation writes the tooth number inside a quadrant bracket. Convert one tooth or a whole list from a chart or referral letter, see Palmer in its proper symbols, and check which permanent tooth replaces each baby tooth.

How it works

Choose permanent (adult) or primary (baby) teeth and the notation you are starting from.
Enter the tooth number or click a tooth on the chart; the result shows Universal, FDI and Palmer with the tooth name.
To convert many teeth at once, paste a list such as “3, 14, 19, 30” or “16 26 36 46” and pick its notation.
Palmer is shown both with the quadrant symbol (6⏌) and as a text-safe code (UR6) that survives email and billing systems.
For baby teeth, the result names the permanent tooth that erupts in its place.

Use cases

Translate tooth numbers from US patient records to international ISO/FDI format.
Convert a whole treatment plan or referral list from FDI to Universal in one step.
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.
Prepare claims that require Universal numbering from FDI source data.

Frequently Asked Questions

Last updated: 2026-10-09 · Reviewed by Nham Vu