At What Age Does The Anterior Fontanelle Close? | Normal Age

The top soft spot usually closes between 7 and 19 months, with many babies closing near 12–14 months.

Your baby’s “soft spot” can feel a bit nerve-racking the first time you notice it. It’s squishy. It pulses. It changes a little with crying. All of that can be normal.

This article explains when the anterior fontanelle (the larger soft spot on the top-front of the head) tends to close, what “normal” looks like month to month, and which patterns are worth a call to your child’s doctor.

Heads grow at different speeds. So do fontanelles. The goal is to understand the usual range, then spot the outliers that deserve a closer check.

What The Anterior Fontanelle Is And Why Babies Have It

The anterior fontanelle is a gap where several skull bones meet. In newborns, those bones aren’t fused yet. That flexible design helps during birth and gives the brain room as it grows.

Over time, the edges of those bones gradually harden and meet. When that gap becomes bone, the fontanelle is “closed.” You may still feel a seam where the bones joined, since the sutures remain as lines between bones.

Most babies have more than one soft spot. The small one in the back (posterior fontanelle) tends to close early, often in the first couple of months. The anterior fontanelle stays open longer. MedlinePlus summarizes that pattern and gives a typical closure window for each. MedlinePlus: Fontanelles (sunken).

At What Age Does The Anterior Fontanelle Close? By The Numbers

For many babies, the anterior fontanelle closes sometime in the second year of life. A commonly cited window is 7 to 19 months, with a midpoint near 13–14 months. Children’s Hospital Colorado uses the same broad range and notes that closure by about 18 months is typical for many infants. Children’s Hospital Colorado: Fontanelle closures.

Those numbers can feel wide, and that’s the point. A baby at 9 months with an open soft spot can be fine. A baby at 16 months with an open soft spot can be fine. Your pediatric visits matter because the fontanelle is only one piece of the story.

Family doctors often reference a median closure time near 13.8 months, drawn from clinical reviews of normal size and closure timing. The American Academy of Family Physicians lays out that median and also explains how the fontanelle exam fits into a full head and neurologic check. AAFP: The abnormal fontanel.

Why The “Normal” Range Is So Wide

Brain growth is fastest in the first year, then it slows. The skull responds to that growth, so the closure pace is not identical for each child.

Genes, birth history, and overall growth patterns can shift the timeline from one baby to the next.

What Closure Looks Like In Real Life

Closure is gradual. You usually don’t wake up one day to a hard, flat skull where a soft spot was yesterday.

Instead, you may notice the soft spot feels smaller, firmer at the edges, or harder to find during calm moments. During crying, it may look fuller for a minute, then settle back down.

A flat, soft fontanelle while your baby is relaxed is a common “normal” pattern. A persistently bulging spot or a markedly sunken spot is a reason to call your child’s doctor, since those patterns can link to dehydration or pressure changes. MedlinePlus describes those signs in plain language. MedlinePlus: Sunken fontanelle signs.

How Clinicians Check The Soft Spot During Routine Visits

During well-baby visits, clinicians check the fontanelle feel, head shape, and head growth over time.

The exam is quick. They’ll gently feel the soft spot and nearby sutures, checking for a normal give instead of a rigid ridge.

Head circumference matters most. Clinics chart it across visits and watch for sudden jumps or stalls.

If your baby has a helmet for plagiocephaly, a family history of early suture fusion, or a head shape change, the fontanelle gets extra attention. A UK NHS pediatric referral guide flags fontanelle tension and closure timing as part of assessing infants with large heads. NHSGGC: Infant with a large head.

What You Can Track At Home Without Obsessing

You don’t need daily checks. A calm, once-in-a-while feel can help you get familiar with what’s normal for your baby.

• Check when calm. A soft, flat spot is common.
• Notice patterns. A bulge that stays while calm or a sunken spot that doesn’t improve after fluids deserves a call.
• Watch head shape. A new ridge or fast shape change matters.
• Pair it with behavior. Fever, repeated vomiting, or unusual sleepiness changes the urgency.

Timing Ranges And What They Often Mean

The table below pulls common timing ranges into one place. It’s not a diagnosis tool. It’s a way to match what you see with what clinicians often expect at different ages.

Age Range	What The Anterior Fontanelle Often Feels Like	What Clinicians Usually Check Alongside It
Birth to 2 months	Soft, easy to feel; can pulse; may look fuller during crying	Posterior fontanelle closure trend; feeding and hydration
2 to 6 months	Still open; edges may feel firmer; size varies a lot	Head circumference curve; head shape from above
6 to 9 months	Often smaller; harder to find during calm moments	Neck mobility, torticollis signs, positional flattening
9 to 12 months	Many babies still have an open spot; gradual firming continues	Growth trend across visits; development milestones
12 to 18 months	Closure is common in this window; spot may be tiny or nearly gone	Any ridging over sutures; persistent asymmetry
18 to 24 months	Most are closed by this point, though late closure can occur	Thyroid, bone, or pressure clues if still widely open
Any age with a fixed ridge	Fontanelle may feel small or absent with a hard ridge near it	Head shape pattern suggesting early suture fusion
Any age with persistent bulging	Full, tense soft spot while calm	Illness signs, fever, hydration, neurologic exam

Early Closure: When A Small Or Closed Soft Spot Raises Questions

An anterior fontanelle that feels unusually small early on can still be normal, especially if head growth stays on track and the head shape looks typical.

Clinicians start to worry when early closure comes with a head shape change or a firm ridge along a suture. That pattern can point to craniosynostosis, where one or more sutures fuse sooner than expected.

In craniosynostosis, the skull may grow more in one direction to make room, leading to a distinctive shape pattern. AAFP’s clinical review explains why a careful fontanelle and suture exam matters when head shape shifts. AAFP: Findings tied to abnormal fontanelles.

Signs That Often Come With Early Suture Fusion

• A new ridge that feels like a raised line and doesn’t soften
• Head shape that becomes more asymmetric over weeks
• Head circumference that drops across percentiles over time
• Eyes that look uneven in height or spacing as the skull shape shifts

If you notice these patterns, call your child’s doctor and ask what timeline makes sense for an in-person exam.

Late Closure: When The Soft Spot Stays Open Longer

A soft spot that stays open past 18 months can still be benign, yet it often triggers a closer look. Clinicians will usually revisit growth charts, nutrition, and the rest of the physical exam.

Several medical conditions can be linked with delayed closure, including certain bone and endocrine disorders. AAFP lists some of the more common medical causes clinicians think about when the fontanelle is large or closure is delayed. AAFP: Causes of delayed closure.

Late closure also needs context. A baby with a steady head circumference curve and normal exam may just be on the slower end of the usual range.

What Clinicians Often Do Next

Next steps depend on the full picture. A clinician may re-measure head size, review growth and feeding, and order tests or imaging when the exam points that way.

When To Treat It As Urgent

Most parents first notice the soft spot during routine care. Still, some patterns call for same-day medical advice.

Call your child’s doctor urgently, or seek emergency care, if your baby has a persistently bulging fontanelle while calm, especially with fever, vomiting, unusual sleepiness, or a high-pitched cry. Clinicians treat that combination as a possible sign of rising pressure or infection that needs fast evaluation.

A markedly sunken fontanelle with dry mouth, low wet diapers, or poor feeding can point to dehydration. MedlinePlus notes sunken fontanelles as one sign among others that can show fluid loss. MedlinePlus: Sunken fontanelle overview.

What You Notice	What It Can Point To	What To Do Next
Bulging soft spot while calm	Pressure change, infection, or illness needing rapid assessment	Seek same-day medical advice
Sunken soft spot plus dry mouth or few wet diapers	Dehydration	Call your child’s doctor promptly; consider urgent care if severe
Hard ridge along a suture	Early suture fusion pattern	Schedule an exam soon; ask about imaging needs
Rapid head size increase across visits	Hydrocephalus or other causes of head growth acceleration	Call your child’s doctor; ask about same-week evaluation
Soft spot still wide open after 18–24 months	Slower closure, endocrine or bone causes	Discuss at the next visit; earlier if growth is off-track

How To Get The Most Out Of Your Next Checkup

If your baby’s fontanelle timing has been on your mind, bring specifics. It helps your clinician sort normal variation from a pattern worth testing.

• Write down when you first noticed a change in size or feel.
• Bring photos from a consistent angle if head shape seems different.
• Ask where your baby’s head circumference sits on the chart and how it has tracked.
• Ask what signs would change the plan between visits.

Most of the time, the outcome is simple reassurance and a plan to keep tracking growth at routine visits.

Takeaway: Normal Range With Clear Guardrails

Most anterior fontanelles close between 7 and 19 months, with many closing near the middle of that range. The growth curve and head shape often matter more than the exact month.

If you see a persistent bulge while calm, a sunken spot with dehydration signs, or a hard ridge with head shape change, call your child’s doctor for guidance.