Dental Formula Calculator

What is a dental formula?

A dental formula is a short way to write how many of each kind of tooth a mammal has. It lists the incisors (I), canines (C), premolars (P) and molars (M) on one side of the mouth, with the upper jaw over the lower jaw.

An adult human has 2 incisors, 1 canine, 2 premolars and 3 molars in each quarter of the mouth. So the formula is I2/2 C1/1 P2/2 M3/3, often shortened to 2.1.2.3/2.1.2.3. Add the numbers and double them to get 32 teeth.

Biologists use formulas to compare species and to help identify a skull. They're also a standard part of vet, zoology and dental courses, which is why the quiz below exists.

How to read and write a dental formula

1. Pick one side. Start at the middle of the upper jaw and count backward: incisors, then canines, premolars and molars.
2. Do the same for the lower jaw on the same side.
3. Write upper over lower for each tooth type, in the order I, C, P, M. Write 0 when a type is missing. Rabbits, for example, have 0 canines.
4. Add up and multiply by 2. The left and right sides mirror each other, so total = 2 × (upper + lower).

Worked example for a dog: the upper side has 3 + 1 + 4 + 2 = 10 teeth and the lower side 3 + 1 + 4 + 3 = 11. So 2 × (10 + 11) = 42 teeth.

Books write the same formula in different ways. The tool reads all of these:

How this tool works

Calculator. Type a formula in any style above, set the numbers in the grid, or pick an animal. The tool adds the upper and lower numbers and doubles them: total = 2 × (upper + lower). It also shows the number of each tooth type in the whole mouth, draws the full set of teeth, and lists any animals in our table with the same formula. If you type a total such as "= 16", it warns you when that total doesn't match. A common slip is giving one side only.

Animal list. We checked all 43 formulas (36 kinds of mammal, plus baby teeth and a horse variant) against the Merck Veterinary Manual, a University of Texas at El Paso table of North American mammals, Texas Tech's Mammals of Texas, the University of Michigan's Animal Diversity Web and the ADA. Each one links to its source. Where a source gives only the formula, we added up the total ourselves.

Quiz. Each question shows a formula and asks for the animal, or the reverse. The wrong answers never share the right answer's formula, so there's always exactly one right choice. Pick "All mammals" for harder questions.

Check my formula. Choose an animal and write its formula. The tool marks each number right or wrong without giving the answer away, until you ask for it. It accepts published ranges, such as a horse's wolf teeth, and the other way of counting the lower canine in cattle, sheep and goats.

Limits. A formula describes a typical animal, and individuals vary. Merck notes that some cats lack an upper premolar or molar, and that hedgehog formulas vary. Close relatives can differ too: bat formulas change a lot from species to species. Some teeth don't fit the four types. The UTEP table lists armadillos with one count of 7 or 8 cheek teeth per side, instead of separate premolars and molars.

Human and animal formulas compared

A few patterns stand out:

• Rodents and rabbits have no canines. Rats, mice and hamsters have just one incisor per quarter and no premolars.
• Cattle, sheep, goats, deer and giraffes have no upper incisors. Merck notes that many books count the cattle, sheep and goat lower canine as a fourth incisor, which gives 0.0.3.3/4.0.3.3. Both add up to 32.
• Pigs keep the full basic set for placental mammals, I3/3 C1/1 P4/4 M3/3 = 44 (Animal Diversity Web).
• Great apes share our formula, and so do Old World monkeys such as baboons. New World monkeys such as capuchins have one more premolar per quarter, for 36 teeth.
• Marsupials have more incisors. The opossum's 50 teeth follow the basic marsupial pattern, I5/4 C1/1 P3/3 M4/4.

Baby (deciduous) and adult (permanent) formulas

Baby teeth get their own formula, usually marked with a "d" for deciduous. Merck writes a puppy's as Di 3/3, Dc 1/1, Dp 3/3. Merck's baby-teeth formulas have no molars: the baby cheek teeth are written as premolars, and molars appear only in the adult formulas.

People are the exception in naming. The ADA calls a child's back teeth baby molars, so the child formula is usually written 2.1.0.2/2.1.0.2. Tick "Baby (deciduous) teeth" in the calculator to switch the labels.

Timing differs a lot. Puppy teeth start coming in at 3–5 weeks, and dogs usually have all their adult teeth by 7 months (Merck). Children usually get their first baby teeth at about 6–10 months (ADA). See when each human tooth arrives in the Tooth Eruption Chart and the Teething Calculator.

Tips for students

• Count one side, then double. Forgetting the "× 2" is the most common mistake. A total that's odd means a slip somewhere.
• Keep the order I, C, P, M and always put the upper jaw first.
• Write zeros. A rabbit is 2.0.3.3/1.0.2.3, not 2.3.3/1.2.3.
• Watch the tricky ones: horse canines and wolf teeth, and the ruminant lower canine.
• Test yourself with the quiz above, then use "Check my formula" for the animals you missed.

For human tooth numbers rather than counts, use the Tooth Number Chart.

Frequently asked questions

Sources

1. Merck Veterinary Manual. Table: Dental Formulas of Various Animal Species. Horse, cattle, sheep, goat, pig, dog and cat, with baby-teeth formulas. Accessed October 26, 2026.
2. Merck Veterinary Manual (Muylle S.). Dental Development of Dogs. last updated June 2025. Accessed October 26, 2026.
3. Merck Veterinary Manual (Muylle S.). Dental Development of Cats. last updated June 2025. Accessed October 26, 2026.
4. Merck Veterinary Manual (Easley J.). Dental Development of Horses. last updated May 2026. Accessed October 26, 2026.
5. Merck Veterinary Manual. Table: Physiological Data for Guinea Pigs. Accessed October 26, 2026.
6. Merck Veterinary Manual (Doss GA.). Overview of Four-Toed (African Pygmy) Hedgehogs. last updated September 2026. Accessed October 26, 2026.
7. Animal Diversity Web, University of Michigan. Differentiation of teeth in an individual. Accessed October 26, 2026.
8. American Dental Association (MouthHealthy). Eruption Charts. Names the 20 baby teeth: in each quarter, two incisors, a canine and two molars. Accessed October 26, 2026.
9. University of Texas at El Paso, Laboratory for Environmental Biology. Dental Formulas: North America North of Mexico. last updated August 19, 2009. Upper and lower counts per side for about 60 North American genera. Accessed October 26, 2026.
10. Texas Tech University, Natural Science Research Laboratory (The Mammals of Texas, online edition). Species account of the White-tailed Deer. Accessed October 26, 2026.
11. Animal Diversity Web (Silberstein M.). Leporidae (hares and rabbits). 2011. Accessed October 26, 2026.
12. Animal Diversity Web (Poor A.). Cricetidae (New World rats and mice, voles, hamsters, and relatives). 2005. Accessed October 26, 2026.
13. Animal Diversity Web (Massiha R.). Chinchillidae (chinchillas and viscachas). 2023. Accessed October 26, 2026.
14. Animal Diversity Web (Howard M.). Loxodonta africana (African bush elephant). 2017. Accessed October 26, 2026.
15. Animal Diversity Web (Myers P.). Camelidae (camels, llamas, and relatives). 2000. Accessed October 26, 2026.
16. Animal Diversity Web (Naumann R.). Camelus dromedarius (dromedary). 1999. Accessed October 26, 2026.
17. Animal Diversity Web (Myers P.). Hominidae (great apes and humans). 2001. Accessed October 26, 2026.
18. Animal Diversity Web (Myers P.). Cercopithecidae (Old World monkeys). 2000. Accessed October 26, 2026.
19. Animal Diversity Web (Dewey T.). Cebidae (marmosets, tamarins, capuchins, and squirrel monkeys). 2008. Accessed October 26, 2026.
20. Animal Diversity Web (Myers P.). Hyaenidae (aardwolf and hyenas). 2000. Accessed October 26, 2026.
21. Animal Diversity Web. Giraffidae (giraffes and okapis). 2000. Accessed October 26, 2026.
22. Animal Diversity Web (Ratzloff E.). Orycteropus afer (aardvark). 2011. Accessed October 26, 2026.
23. Animal Diversity Web (Dulal D.). Ceratotherium simum (white rhinoceros). 2017. Accessed October 26, 2026.
24. Bixler H, Ellis C. Veterinary Clinics of North America: Exotic Animal Practice 2004;7(2). Ferret care and husbandry. 2004. Accessed October 26, 2026.

Last reviewed October 26, 2026 by the Dental Health Time editorial team, against the sources above. How we review.