Baby Teeth Count Calculator

Expected baby teeth by age in months.

Health and FitnessUpdated 2026-10-122 min read
Baby Teeth Count Calculator
Teeth expected
...
Teeth left...
Molar guide...

What it does

Twenty baby teeth arrive on a rough schedule. Nothing before six months, then a steady march to a full set near the second birthday, with molars punctuating the middle. Parents count along the way.

The tool above draws that line. At 12 months it expects 7 teeth with about 13 to go and first molars near 13-19 months. At 24 months it shows the full 20 with second molars near 25-33 months behind. At 3 months it shows zero with all 20 ahead.

Averages hide wide normals. First teeth land anywhere from four to ten months, and order shuffles between babies. Fever, rash, or poor feeding never belong to teething alone in this math.

This page entertains curiosity only. It does not diagnose delays or dose medicines. Dental and pediatric visits own milestones.

How to use

  1. Enter the age in months.
  2. Read expected teeth first.
  3. Read remaining to 20.
  4. Read the molar guide line.
  5. Compare loosely, not strictly.
  6. Ask the dentist about big gaps.

Formula

teeth = 0 below 6 mo, else min(20, round((months-6) x 20/18)). Remaining = 20 - teeth.
months
Child age in months, 0 to 36.
teeth
Expected erupted count, rounded.
left
20 minus expected.

Straight line average from first tooth near 6 months to 20 near 24 months, capped at 20. At zero to five months the answer is zero. Real babies vary by many months either way.

Worked example

Example: 12 month old

Defaults: 12 months. First tooth often near 6 months with 20 by age 3.

  1. Inputs: 12 months old.
  2. Math: (12 minus 6) times 20 / 18 is 6.67.
  3. Rounded: 7 teeth.
  4. Left: 20 minus 7 is about 13 to go.
  5. First molars land 13-19 mo. Tool shows the same.

Reference table

Average line checks
AgeExpectedGuide
12 months7 teethfirst molars near 13-19 mo
24 months20 teethsecond molars near 25-33 mo
3 months0 teethfirst molars near 13-19 mo
18 months13 teethfirst molars near 13-19 mo
9 months3 teethfirst molars near 13-19 mo

Limits

  • Average only. Wide normals.
  • No diagnosis of delays.
  • No fever guidance.
  • To 36 months window.

Common mistakes

  • Treating average as deadline.
  • Blaming high fever on teeth.
  • Counting gum bulges as teeth.
  • Comparing siblings strictly.
  • Skipping dental visits.

Try it yourself

Quick checks. Answers sit tucked under each question.

24 months old?

Count is 20 teeth with a full set of 20. Second molars near 25-33 mo.

3 months old?

Count is 0 teeth with about 20 to go. First molars near 13-19 mo.

Questions

How is the count figured?

Linear from 0 at 6 months to 20 near 24. Here 7 teeth.

How many remain?

20 minus expected. Here about 13 to go.

When does the first tooth come?

Near 6 months, sometimes 4 to 10. Timing varies widely.

When do molars come?

First molars 13-19 mo, second 25-33 mo, set done near 3 years.

Does teething cause high fever?

No. Fever with teething needs the pediatrician, not the chart.

Is late teething a problem?

No. This is a population average for curiosity, not a milestone diagnosis.

Sources

How this page was checked. The formula above was matched against the cited sources, and the worked example was run through the tool on this page before publishing. If you spot an error, contact us so we can fix it and note the correction.