At What Age Does The Fontanelle Close? | The Timing Parents Notice

Most babies’ soft spots shrink steadily after birth, with the back one closing in 1–2 months and the top one closing in the wide 7–19 month range.

A baby’s “soft spot” can feel like a tiny mystery. One day you can spot it easily, the next day it seems smaller, flatter, or harder to find. That swing is normal, and it’s also why this topic sends parents to search at 2 a.m.

You’ll get clear closure windows, what you can safely check at home, and the signs that mean your baby needs medical care now. Near the end, there’s a simple checklist you can use between well-baby visits.

What The Fontanelle Is And Why Babies Have One

Fontanelles are flexible gaps where skull bones meet before they fuse. They let a baby’s head mold during birth and give the brain room to grow quickly in the first year. The “soft” part is not a hole into the brain. A tough membrane covers it.

Most babies have more than one fontanelle at birth. Two matter most for parents because they’re easiest to find: the posterior fontanelle (back of the head) and the anterior fontanelle (top-front of the head).

At What Age Does The Fontanelle Close? Typical Ranges

There isn’t one single date when every baby’s soft spot closes. Clinicians use a normal range. The back soft spot tends to close first, often by 1 to 2 months. The top soft spot closes later, most often within 7 to 19 months. These windows match common clinical references used in everyday care, like the MedlinePlus medical encyclopedia entry on fontanelles that look bulging.

That wide range is still normal. It’s also why you can’t judge “early” or “late” from a single touch on a random day. Well-baby visits track the trend over time, along with head growth, feeding, and development.

What “Closed” Usually Feels Like

Many parents expect a sudden snap from soft to hard. Lots of babies close in a slower, quieter way. The edges feel firmer first. Then the soft area gets smaller until you can’t find it without hunting. Some days it can feel flatter, then feel a little fuller during crying or straining.

Why The Ranges Differ Between Babies

Two babies can be equally healthy and still close at different ages. Head size, the shape of skull plates, and genetic variation all play a part. Clinicians also check head circumference curves, since that shows growth far better than a single “soft spot” check.

How To Check A Soft Spot Without Overthinking It

You don’t need special skills. You only need a calm baby and gentle hands.

Step-By-Step Home Check

1. Pick a calm moment, like after a feed or after a diaper change.
2. Use the pads of two fingers, not your fingernail.
3. Feel for a soft, slightly springy area, not a sharp edge.
4. Notice the level: flat with the skull, a little inward curve, or raised.
5. Stop if your baby dislikes it. You can try again another day.

A soft spot can pulse. That can look odd the first time you see it, yet it can be normal. The American Academy of Pediatrics’ parent guidance on a baby’s head and soft spots describes visible pulsing as a normal finding in many infants.

What Changes During Crying, Vomiting, Or Straining

Crying and straining can raise pressure in the head for a short time. The soft spot may look fuller while the baby is upset. What matters is what you see when your baby is calm again. A soft spot that stays bulged when your baby is resting needs urgent medical assessment.

Fontanelle Closing Age By Spot And Baby Growth

Thinking in “which spot” helps, since each one has its own rhythm. The back soft spot is small and tends to close early. The top one is larger and stays open longer. Side fontanelles exist too, though most parents never notice them because hair and head shape hide them.

If you want a clear view of the usual pattern, use the table below. It pairs the “where” with the closure window you’ll often hear at checkups.

Closure Timing Table For Common Fontanelles

Fontanelle	Where You’d Find It	Usual Closure Window
Anterior (Top-Front)	Near the crown, toward the forehead	Often 7–19 months
Posterior (Back)	Back of the head	Often 1–2 months
Sphenoidal (Left)	Temple area, above the cheekbone	Often within the first months
Sphenoidal (Right)	Temple area, above the cheekbone	Often within the first months
Mastoid (Left)	Behind the ear	Often within the first year
Mastoid (Right)	Behind the ear	Often within the first year
Metopic Suture Area	Midline of the forehead	Timing varies; assessed at checkups

Only two rows use a tight month range. That’s on purpose. Parents can track the top and back fontanelles at home. The side fontanelles are less useful for day-to-day checks, and clinicians interpret them with the full head exam.

What Can Make Closure Seem Early Or Late

Parents often worry about “closing too soon” after a growth spurt or after hair thickens. Both can make the soft spot harder to find. The same thing happens when the fontanelle is small from the start. Small can still be normal if head growth stays on track.

Head Shape And Positioning

A flat area on the back of the head can shift where the posterior fontanelle sits. That can throw off your sense of where to feel. If you’re unsure, use the next well-baby visit to ask your clinician to point it out once. After you feel it with them, it’s easier to find at home.

Premature Closure And Craniosynostosis

One reason clinicians care about early closure is craniosynostosis, where one or more skull sutures fuse too soon. The clue is not just “I can’t feel the soft spot.” The clue is an unusual head shape or a head circumference curve that stops rising as expected. That’s why routine measurements matter so much.

Later Closure And What It Can Mean

Later closure can happen with conditions that affect bone growth or thyroid function. It can also be normal variation. Clinicians tie this to the full picture: growth, muscle tone, feeding, and other exam findings. A classic clinical overview of causes linked to abnormal size or delayed closure is outlined by the American Academy of Family Physicians in “The Abnormal Fontanel”.

When A Soft Spot Needs Medical Care

Most soft spot questions are routine. A small set of signs need fast action. These are clear signals that something may be wrong with hydration, infection, or pressure in the skull.

How A Normal Soft Spot Should Look Most Days

When your baby is calm, a normal fontanelle is flat with the skull or has a mild inward curve. You may see a gentle pulse. You might also notice the soft spot looks a bit fuller during crying. Check again once your baby settles.

Red-Flag Table For Fontanelle Changes

What You See	What It Can Point To	Next Step
Bulging soft spot while calm	Raised pressure in the skull	Seek urgent medical care now
Sunken soft spot plus dry mouth or low urine	Dehydration	Call for same-day medical advice
Soft spot change after a head injury	Injury or bleeding risk	Seek urgent medical care now
Fever in a young infant plus unusual sleepiness	Possible serious infection	Seek urgent medical care now
Soft spot closes early plus head shape that keeps changing	Suture fusion (craniosynostosis)	Book a prompt clinical review
Soft spot stays wide past the expected range	Bone or thyroid issues, or normal variation	Bring it up at the next visit, sooner if other signs appear

Use symptoms alongside the soft spot. Fever, poor feeding, repeated vomiting, breathing trouble, or a baby who is hard to wake are reasons to seek care. Mayo Clinic’s guidance on when to seek medical attention for a sick baby gives a clear list for those moments.

What Clinicians Check At Well-Baby Visits

At checkups, clinicians do more than a brief press on the soft spot. They measure head circumference and plot it on a growth chart. They feel sutures and look at head shape from multiple angles. They also check the fontanelle’s tension while the baby is calm.

This is why a soft spot question is best answered with trend data. If your baby has been tracking along a steady growth curve and acts well, a soft spot that is hard to find one week is often just normal change.

What You Can Bring To The Appointment

• Photos that show head shape over time, taken from similar angles.
• A note of when you first noticed the change and whether it comes and goes.
• Other symptoms: feeding changes, fewer wet diapers, fever, vomiting, sleep changes.

Everyday Care For The Soft Spot

You can wash your baby’s hair, brush it, and gently touch the scalp. Normal handling won’t harm the soft spot. Use the same light pressure you’d use on an eyelid. If your baby has cradle cap, treat it as you normally would, while staying gentle.

Common Misreads That Cause Worry

• A pulse you can see. This can be normal, especially in quiet moments.
• A soft spot that “vanishes” under thicker hair. Hair growth can hide it.
• A soft spot that looks a bit full during crying. Check again once calm.
• A slight inward curve. A mild dip can be normal if your baby is drinking well.

A Simple Soft Spot Checklist For Parents

Use this list as a steady way to check the full picture between visits.

• Baby is feeding as usual.
• Wet diapers follow your baby’s usual pattern.
• Soft spot is flat or mildly inward while calm.
• No bulge that persists when resting.
• No new head-shape change that is getting worse.
• Baby is alert in their normal windows and not hard to wake.

If one item stands out, write it down and bring it to the next visit. If several stand out, or your baby seems unwell, seek care the same day. Trust your gut. You know your baby’s normal better than anyone.

So What Age Should You Expect It To Close?

Most parents see the back soft spot fade in the first couple of months. The top one often sticks around through much of the first year and can stay open into the second year. If your baby is within the 7–19 month window for the anterior fontanelle and is growing well, that’s usually within normal bounds.

If your baby is outside those ranges, don’t panic. Use the full picture: head growth trend, head shape, and how your baby acts. Bring it up at the next checkup, or sooner if you also see warning signs like a persistent bulge, dehydration clues, fever, or unusual sleepiness.