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How old is my baby?
Enter a birth date to see your baby's age in days, weeks and months. Born early? Add the due date for corrected age and the right feeding stage.
Pick your baby's birth date to see their age.
How do you calculate a preemie's corrected age?
Subtract the weeks your baby was born early from their actual age. Weeks early is 40 minus the weeks of pregnancy at birth. A baby born at 32 weeks is 8 weeks early, so at 16 weeks old their corrected age is 8 weeks (about 2 months). It equals the time since the due date.
Feeding stages by age
For babies born early, use corrected age.
| Age | Stage | Feeds | Amounts |
|---|---|---|---|
| 0 to 6 days | First days | 8 to 12 feeds in 24 hours | Tiny feeds: colostrum, or about 1 to 2 oz (30 to 60 ml) of formula per feed |
| 1 to 4 weeks | Newborn weeks | 8 to 12 feeds (breast) or about every 3 to 4 hours (formula) | Working up toward about 3 to 4 oz (90 to 120 ml) per bottle by 1 month |
| 1 to 2 months | Settling in | About 7 to 10 feeds a day | Formula: about 2.5 oz per lb per day (up to 32 oz). Breast milk: about 25 oz (750 ml) a day |
| 2 to 4 months | Finding a rhythm | About 6 to 8 feeds a day | Formula: about 2.5 oz per lb per day (up to 32 oz). Breast milk: about 25 oz (750 ml) a day |
| 4 to 6 months | Getting ready for solids | About 5 to 7 feeds a day | Milk is still everything. Formula up to about 32 oz a day |
| 6 to 9 months | First foods | About 4 to 5 milk feeds plus solids | Formula about 6 to 8 oz (180 to 240 ml) a feed. Breast milk about 600 ml a day |
| 9 to 12 months | More textures | About 3 to 5 milk feeds plus 3 meals | Milk feeds shrink a little as meals grow |
| 12 months and up | Toddler | Meals and snacks, plus breastfeeding if you both like | Ask your pediatrician which milk to offer after 12 months |
Typical ranges for healthy babies. 1 oz ≈ 30 ml.
How we calculate this
Age in days = today − birth date. Weeks = days ÷ 7, with the remainder in days. Months are calendar months: a baby born on the 10th turns a month older on each 10th (or the last day of a shorter month).
Corrected age = actual age − (40 weeks − weeks of pregnancy at birth), which is the same as today − due date. We use corrected age for the feeding stage when your baby was born before 37 weeks, following the AAP. All dates use your device's calendar, so nothing is sent anywhere.
When to call your pediatrician
- Your baby born early isn't gaining weight as your care team expected, or feeds take much longer than usual.
- Fewer wet diapers than expected for your baby's age (after day 5, fewer than 6 in 24 hours), or dark yellow urine.
- A temperature of 100.4°F (38°C) or higher in a baby under 3 months. Call right away, day or night.
- Very sleepy, floppy or hard to wake for feeds, or less alert than usual.
- Refusing feeds, or several feeds in a row that are much smaller than usual.
- Signs of dehydration: dry mouth, no tears, a sunken soft spot on the head, or no poop along with very few wet diapers.
- Yellow skin or eyes that's spreading or getting deeper, especially in the first week.
- Forceful or green vomiting, or blood in the poop.
Call 911 (or your local emergency number) if your baby has trouble breathing, turns blue or gray around the lips, or won't wake up.
If something feels off, trust your gut and call. That's what they're there for.
Frequently asked questions
How do I calculate my baby's age in weeks?
Count the days since birth and divide by 7. A baby born 45 days ago is 6 weeks and 3 days old. Doctors and apps often use weeks for the first 3 months, then switch to months. This calculator shows days, weeks and months together.
What is corrected age for a premature baby?
Corrected age (also called adjusted age) is your baby's age counted from the due date instead of the birth date. The AAP example: a baby born at 32 weeks is 8 weeks early, so at 16 weeks old their corrected age is 2 months. Pediatricians use it for growth and milestones.
Until what age do you use corrected age?
Usually until about age 2. By then most babies born early have caught up, and the few weeks' difference matters less. Your pediatrician or NICU follow-up team will tell you what to use for your baby, especially for feeding and starting solids.
When is my baby 3 months old?
On the same date three months after birth. A baby born on January 10 turns 3 months on April 10. That's about 13 weeks. Because months have different lengths, the week count and month count don't line up perfectly, which is why this calculator shows both.
Sources
- American Academy of Pediatrics (HealthyChildren.org): Corrected Age For Preemies(opens in a new tab)
- American Academy of Pediatrics (HealthyChildren.org): Starting Solid Foods(opens in a new tab)
- American Academy of Pediatrics (HealthyChildren.org): Amount and Schedule of Formula Feedings(opens in a new tab)
- Centers for Disease Control and Prevention (CDC): How Much and How Often to Breastfeed(opens in a new tab)
Last reviewed: November 2026
Feedoo Baby shares general information, not medical advice. Every baby is different. If you're worried about feeding, weight gain, diapers or your baby's health, call your pediatrician, midwife or health visitor.
Targets that grow with your baby
Feedoo Baby knows your baby's age and adjusts the daily milk-intake band as they grow, so the numbers you see are for this week, not some other baby's.
- Intake bands by age on the home screen and in Metrics
- Calendar for pediatrician visits, one-off or recurring
- Supplement check-offs for vitamin D or probiotics
- Twins or siblings: switch between babies
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