When Do Babies Start Teething? Signs, Age & Timeline

Most new parents find themselves watching their baby’s gums closely around the six-month mark, wondering when that first tooth will show up. The average age for teething is six months according to the NHS, but the signs can actually appear much earlier — sometimes as young as 13 weeks. And in rare cases, babies are even born with teeth already in place.

Average start age: 6 months ·
Earliest signs: 13 weeks ·
Earliest teeth: 3 months ·
Latest common start: 12 months ·
Process begins: 2-4 months

These key data points from authoritative health sources illustrate the wide normal range for infant teething.

What are the first signs of teething?

The signs of teething often start before anything actually shows through the gums. You might notice your baby drooling more, gnawing on toys, or seeming fussier than usual. The NHS lists the most common symptoms, and they typically appear 3-5 days before the tooth breaks through the gum surface.

Drooling and chewing

• Excess drooling — babies often produce more saliva than usual when teething (Childsmile NHS Scotland)
• Increased chewing and gnawing on toys, fingers, or fists (NHS)
• This behavior starts when tooth movement begins internally at 2-4 months (University of Utah Health)

Gum swelling

• Sore and red gums where the tooth is coming through (NHS)
• You may see white bumps (gingival cysts) or blue bumps (gum hematomas) on the gums — these are normal and resolve once the tooth erupts

Fussiness

• Irritability and general fussiness due to gum discomfort
• Teething symptoms were reported by 70-80% of parents according to the British Dental Journal (Children’s Hospital Los Angeles)
• Rubbing their ear — this is a referred pain from the jaw area

The pattern is consistent: teething symptoms arrive 3-5 days before the actual tooth becomes visible. This means parents have a short window of warning before the eruption, which can help with preparation.

Would a 3 month old be teething?

Yes, some babies show signs of teething by three months. Parents are often surprised to learn this — the common assumption is that teeth don’t start appearing until around six months. But according to the HSE, babies may show signs of teething from about 13 weeks, and the internal tooth movement process actually begins between 2-4 months.

Early teething at 2-3 months

• Signs can appear from 13 weeks (approximately 3 months) (HSE)
• The teething process starts internally when babies are between 2 and 4 months old, with internal tooth movement before visible eruption (University of Utah Health)
• Some babies are born with their first teeth — these are called natal teeth (NHS)
• Others start teething before they are 4 months old, and some after 12 months (NHS)

Signs in young infants

• Intense drooling and chewing — often the first noticeable signs
• Fussiness and irritability due to gum discomfort
• Sore, red gums where teeth are moving beneath the surface
• Rubbing ears or cheeks

Premature babies

• Premature babies may follow their corrected age for developmental milestones including teething
• If there are no signs of teeth appearing by 14 months, seek dental advice (HSE)

The variation in teething timing is remarkable — while the average is six months, healthy babies can show signs from 13 weeks all the way to 12 months or later. If your young infant seems uncomfortable with symptoms that match the teething profile, that’s completely within the normal range.

What age is teething the worst for babies?

Around six months, babies typically get their first teeth — and many experience significant discomfort during this milestone. However, the age when teething seems most difficult varies, and certain teeth tend to cause more trouble than others.

Peak discomfort periods

• The first tooth eruption at around 6 months often causes notable discomfort (NHS)
• First molars (back teeth) at 12-16 months can be particularly challenging — these are larger teeth breaking through wider gum areas (NHS)
• Second molars at 20-30 months may also cause significant discomfort as toddlers approach their full set of 20 baby teeth

Worst months

• Many parents report the 6-month period as particularly rough — coinciding with the first visible tooth and the loss of maternal immunity
• The process typically continues with varying intensity until all 20 baby teeth emerge, usually by 2.5 years (HSE)

Incisor emergence

• Bottom incisors usually come through at 5-7 months — often the first and among the least painful
• Top incisors at 6-8 months typically emerge with moderate discomfort

The pattern suggests that larger teeth (molars and canines) tend to cause more discomfort than incisors. Parents should be prepared for potential flare-ups around 12-16 months and again around 20-30 months when the larger back teeth emerge.

What can be mistaken for teething?

Many parents assume that fever or diarrhoea means a baby is teething, but there’s actually no evidence supporting this connection. According to the NHS, it’s important to distinguish between teething symptoms and signs of actual illness.

Illness vs teething

• High fever with cold and flu symptoms is not related to teething — it’s a sign that an infant is sick (Children’s Hospital Los Angeles)
• There is no evidence that teething causes diarrhoea and fever (NHS 111 Wales)
• A mild temperature of less than 38°C may occur with teething, but anything higher should be investigated (NHS)
• Teething occasionally may cause a slight rise in temperature but not over 101°F (38.3°C) (HealthyChildren.org)

Fussiness causes at 3 months

• The 3-month fussiness phase is often incorrectly attributed to teething
• Growth spurts, developmental leaps, and gas can all cause similar symptoms
• If symptoms seem severe or prolonged, consult a healthcare provider

Other symptoms

• Teething may cause a mild rash on a baby’s chin or neck, but it does not cause a widespread rash (HSE)
• Widespread rashes should be evaluated by a healthcare provider

The implication is clear: parents should resist the urge to attribute every fever or bout of diarrhoea to teething. When in doubt, treating symptoms as potential illness is the safer approach.

What are the early signs of teething?

The earliest signs of teething appear well before any tooth is visible. According to the HSE, you may spot the first signs of teething at around three months, and the teething process itself starts internally months before eruption.

Earliest indicators

• Sore, swollen gums that look red or inflamed at the eruption site
• Dribbling more than usual — this can start from 13 weeks (HSE)
• One flushed cheek, though sometimes both cheeks can appear rosy
• Rubbing their ear — referred pain from the jaw area
• Gnawing and chewing on things a lot (NHS)
• A mild temperature of less than 38°C may occur (NHS)

Breastfed babies

• May clamp down on the breast more frequently or seem fussy during feeds
• May pull off the breast repeatedly due to gum discomfort
• The pressure of sucking can sometimes provide relief, while other times it may increase discomfort

Pain signals

• General fussiness and irritability
• Changes in sleep patterns
• Loss of appetite or changes in feeding behaviour
• Teething symptoms typically appear 3-5 days before the actual tooth emerges

What this means: teething signs precede visible teeth by days, not weeks. If you notice these behaviours, expect a tooth within the week. Understanding this timeline helps parents anticipate rather than react to teething symptoms.

“Teeth do not usually appear until a baby is 6 months old or later. They may show signs of teething from about 13 weeks.”

— HSE (Health Service Executive Ireland)

“Some babies are born with their first teeth. Others start teething before they are 4 months old, and some after 12 months.”

— NHS (UK National Health Service)

“On average, infants start teething around 6 months old, but some babies might have teeth come in as early as 3 months.”

— Children’s Hospital Los Angeles (paediatric hospital)

For new parents, the key takeaway is this: teething has a wide normal range. While six months is average, signs can appear from 13 weeks — and some babies are even born with teeth. Watch for the classic signs (drooling, chewing, gum redness), use appropriate comfort measures like cold teething rings, and always treat fever over 38°C as a potential illness requiring medical attention. If you’re concerned about timing — either too early or no teeth by 14 months — speak with your GP or paediatrician.