Baby growth spurt chart and calculator (0–6 months)

Enter your baby’s birth date to put the growth spurt windows on a calendar: 7–10 days, 2–3 weeks, 4–6 weeks, 8, 12 and 16 weeks and about 6 months.

What this tool does

Plug in your baby’s birth date and get the commonly reported growth spurt windows from newborn to six months (7–10 days, 2–3 weeks, 4–6 weeks, 8, 12, 16 weeks, ~6 months). It’s a simple planner: quick dates, short notes, and realistic expectations.

Further down this page there is also a growth spurt signs checker that compares a spurt with overtiredness, a 3-day plan for the hungry, unsettled days and a cluster feeding planner for the evenings.

How to use it

  1. Enter the birth date.
  2. The top card shows the window your baby is in now, or the next one, with its dates. The timeline marks today and each window as now, next or past.
  3. Tap any window on the timeline for what parents commonly notice and a few things to try.

Growth spurt calendar (the windows we use)

WindowDays after birth
7–10 daysdays 7–10
2–3 weeksdays 14–21
4–6 weeksdays 28–42
8 weeksdays 56–60
12 weeksdays 84–88
16 weeksdays 112–116
Around 6 monthsdays 168–182

What you’ll see

  • Dates for each window + duration in days
  • A status: Happening now, in 3 days (or weeks, months), or 2 weeks ago
  • Short tips for each window (feed on demand, shorten wake windows, keep evenings calm), with a safe sleep note where a tip mentions naps

Good to know

  • Windows are approximate. A few days earlier or later is common.
  • This does not diagnose anything. If you see red flags (fever, fewer wet diapers, breathing trouble), call your clinician.
  • For the 4–6 week window, see our 6-week growth spurt guide. If your baby feeds less rather than more, read when it is not a growth spurt.

Common signs of a growth spurt

  • More frequent feeding. Health services describe growth spurts as a few days of wanting to feed more often, commonly in evening clusters (NHS, HSE). For the first couple of months, the AAP tells breastfeeding parents to be prepared for growth spurts that increase a baby’s demand for milk (AAP).
  • Fussier evenings and wanting to be held. Some babies want to nurse every 30 minutes to an hour in the evening (USDA WIC).
  • Changed sleep. The NHS lists growth spurts, teething and illness among the things that affect how a baby sleeps (NHS).
  • Usual or more wet diapers. A hungry baby who is feeding well should keep producing wet diapers. Fewer than usual is a warning sign, not a growth spurt sign.

Growth spurt or sleep regression: how they tend to differ

  • Hunger is the clearest clue. Rough sleep without any change in appetite points more towards the routine side.
  • Duration. A growth spurt is usually described as lasting a few days (USDA WIC). A pattern that drags on for a week or more with long wake windows, short naps and early mornings looks more like overtiredness or a change in sleep needs.
  • Sleep changes are expected either way. All babies change their sleep patterns as they grow, and a simple, repeated bedtime routine helps in both cases (NHS).

Many parenting resources list growth spurts at around 2–3 weeks, 6 weeks, 3 months and 6 months (USDA WIC). Those ages are commonly reported, not proven: a 2024 review found the research on infant growth spurts “scarce” and could not identify a reliable age or rhythm for them (Davanzo & Baldassarre, 2024). Go by the signs in front of you, not the calendar. The same goes for “regression” ages: our sleep regressions guide explains the commonly mentioned ones.

What helps during a growth spurt

  • Follow your baby's lead on feeds. Health services describe babies feeding more often for a few days during a growth spurt, and advise feeding in response to cues rather than a schedule (HSE, NHS). With breastfeeding, more feeding generally means more milk (NHS).
  • Don't overfeed bottles. Hold the bottle nearly horizontal, allow breaks, and don't push your baby to finish (NHS).
  • Look after yourself. You may be hungrier and thirstier, so accept help with meals and diapers and rest when your baby settles (HSE, USDA WIC).
  • Keep bedtime simple and repeatable. The NHS suggests a soothing bedtime routine and expects sleep patterns to change as babies grow (NHS).

Wake-window adjustments are a common parenting approach, not official guidance. A note on contact and motion naps: they can get you through a rough day, but the NHS advises placing your baby on their back in their own crib or Moses basket for sleep, never sleeping with your baby on a sofa or armchair, taking your baby out of the car seat once you arrive, and following the T.I.C.K.S. rules in a sling (NHS).

What cluster feeding is, and why it's common

Cluster feeding is when a baby wants to feed very often for a stretch of time, then goes longer without feeding. It's especially common in the evening, and some babies cluster feed for 2 to 3 hours before they settle (HSE). The NHS says it usually happens in the first 3 to 4 months, can happen during the day or night, and is "nothing to be concerned about". It may last a few days when a baby is going through a growth spurt (NHS).

Some breastfed babies want to nurse every 30 minutes to an hour in the evening (USDA WIC), which is where the planner's shortest gaps come from. Frequent feeding in the early weeks is expected anyway: the CDC puts it at about 8 to 12 feeds in 24 hours (CDC).

Tips for breast, formula and mixed feeding

  • Breastfeeding: feed in response to cues rather than the clock. Breast milk works on supply and demand, so more feeding generally means more milk (NHS). Keep water and a snack close. The HSE notes you may feel hungrier and thirstier during a growth spurt.
  • Formula: you can cluster feed formula, but the NHS warns not to overfeed. Watch for signs your baby needs a break: splayed fingers and toes, milk spilling out, stopping sucking, turning away or pushing the bottle away (NHS). Hold the bottle close to horizontal, let your baby take breaks, and don't push them to finish (NHS).
  • Mixed: keep the evening calm and low-distraction, and offer smaller top-ups when your baby cues rather than large bottles.

When to call a doctor

A growth spurt or cluster-feeding phase should not come with signs of illness. Get medical advice instead of waiting it out if:

  • Your baby has a fever. The NHS says to call 111 if a baby under 3 months has a temperature of 38°C or higher, or a baby aged 3 to 6 months has 39°C or higher. The AAP says to call your pediatrician for any temperature of 100.4°F (38.0°C) or higher in a baby younger than 3 months (NHS, AAP).
  • There are signs of dehydration: fewer wet diapers than usual, a sunken soft spot (fontanelle), sunken eyes, few or no tears when crying, or unusual drowsiness or irritability. The NHS advises an urgent GP appointment or NHS 111 for these (NHS).
  • Diaper output is below the expected level. From day 5 the NHS expects at least 6 heavy wet diapers every 24 hours for a breastfed baby (NHS).
  • Call 999 (or your local emergency number) for difficulty breathing, blue, gray or blotchy skin, a rash that doesn’t fade under a glass, a stiff neck, or a baby who is drowsy and hard to wake or not responding like they normally do (NHS).

If you’re simply worried that your baby isn’t getting enough milk, ask early: your midwife, health visitor, pediatrician or a breastfeeding specialist can check a feed and your baby’s weight.

About this tool: how it’s calculated

The calculator adds the day ranges in the table above to your baby’s birth date and shows each window’s dates, length in days, and whether it is happening now, coming up or past. The windows reflect ages commonly described by parents and feeding resources, not a medical schedule. The NHS notes that babies may cluster feed for a few days during a growth spurt, but a 2024 research review found that fixed growth-spurt ages (such as 2–3 weeks, 6 weeks, 3 and 6 months) are not well supported by evidence. So treat the dates as a prompt to watch your baby’s cues, not a forecast.

Privacy

The birth date stays in your browser and isn’t saved.

Written by the Nurtura Daily team. Sources checked 26 September 2026.

Sources

How accurate are these dates?

They’re typical windows, not guarantees. Expect a few days early or late. Look for the pattern: appetite up, short-term sleep wobble, clingier baby.

Should I use corrected age for preterm babies?

The tool asks only for a birth date. For a preterm baby, you can enter the due date instead so the windows follow corrected age. If unsure, check both and watch the signs.

What if my baby skips a window?

That happens. Some spurts are subtle. Focus on the signs and your baby’s appetite/sleep, not the calendar.

Can I use this for twins?

Yes. Twins share a birth date, so the dates are the same, but expect different timing and intensity for each baby and watch each one’s signs.

Does the tool store birth dates?

No. It runs in your browser and doesn’t save the date.

How often should I check this?

Check when feeding or sleep suddenly change, or at the listed windows. Combine it with the growth spurt signs checker for a clearer read.

When do babies have growth spurts?

They’re commonly described at around 7–10 days, 2–3 weeks, 4–6 weeks, 3 months and 6 months, and the NHS notes babies may cluster feed for a few days during one. Research hasn’t confirmed fixed ages, so your baby’s timing may differ.

Is there a 6-month growth spurt?

Many parents notice hungrier, more unsettled days around 6 months, and the calculator shows a window at 24–26 weeks. Evidence for a set spurt at this age is limited, so if feeding or sleep changes last or you’re worried, check with your health visitor or pediatrician.

What's the main difference between a growth spurt and a sleep regression?

A growth spurt is usually described as a few days of clearly bigger appetite, often with evening cluster feeding. Rough sleep with no change in appetite, longer wake windows, less day sleep and early mornings points more towards the routine side, which is what the tool counts as schedule pressure.

Does fever ever fit a growth spurt?

No. Fever points to illness. For a baby under 3 months, 38°C (100.4°F) or higher needs medical advice straight away. For 3 to 6 months, the NHS says to call 111 at 39°C or higher.

Can formula-fed babies have growth spurts too?

Yes. Any baby can go through phases of wanting more. With formula, offer smaller, paced feeds and follow your baby's cues rather than pushing larger bottles. The NHS warns against overfeeding.

How long does cluster feeding last?

Evening clusters often run for 2 to 3 hours before a baby settles (HSE). When they're linked to a growth spurt, the NHS says they may last a few days. When appetite and sleep settle, drift back to your usual rhythm.

Does cluster feeding mean I don't have enough milk?

Not by itself. The HSE notes that feeding more often during a growth spurt doesn't mean your baby isn't getting enough. Wet diapers are a better check: the NHS expects at least 6 heavy wet diapers a day from day 5. If you're worried, ask your midwife, health visitor or a breastfeeding specialist early.