Premature baby getting a head measure based on corrected age

Corrected Age vs Actual Age: What is it and Why is Important for Preemies

Sharing is caring!

Why is Corrected Age Important to use for Premature Babies

Corrected age and actual age are terms only used in the NICU.

A premature baby’s corrected age is used to give the baby a chance to catch up with milestones.

You will never hear these terms anywhere else.

But once you have a preemie, you are constantly hearing these words.

And it can be confusing!!!

Even as a NICU nurse, it took me a while to understand these two terms.

And now having my own preemie, I have a clear understanding.

So in this blog, I want to break it down for all the NICU parents to have a better understanding what corrected age vs actual is.

I have included a FREE printable you can refer back to whenever you need to calculate the corrected age.

So let’s get started!

When to use corrected age for a premature baby for their milestones

What is Corrected Age for a Premature Baby

The corrected age is the age from their due date.

It’s used to give a preemie baby a chance to reach their milestones.

This is because a preemie is born early and if you use their actual age to see how they are developing, then they will always be behind in everything.

Think about it like this…

When a premature baby is born early, they are still growing and getting stronger.

But the difference is they are growing and getting stronger in the NICU, instead of their mom’s belly.

So technically, a premature baby doesn’t act like a “regular baby” ( in the sense of more awake period, eating on their own, breathing on their own) until they reach full term (40 wks).

This whole time, the preemie is growing and learning outside the womb (ie. in a isolette).

So it is not fair to assess the development of a preemie baby that is 3 wks old because technically this baby is still growing and not doing much.

The corrected age is used to monitor milestones and this starts after due date.

So therefore the actual age is the age from birth.

After the due date is when we treat the baby as a full-term baby and they should start meeting milestones, even though that baby is 2, 3, or 4 months old already.

Therefore, we cannot ignore that the baby was alive this whole time before reaching the due this is the actual age of the baby.

I hope that makes sense.

You can comment down below or email me if you have further questions. 🙂

How do you Calculate the Proper Age for Your Preemie

Get your Corrected Age Calculator Printable

    We respect your privacy. Unsubscribe at anytime.

    A premature baby is born before 37 wks. 

    The accurate corrected age( or adjusted age) is the current age of the premature baby minus the number of weeks early they are born.

    The corrected age only starts after the due date!

    The actual age starts the day they are born.

    To calculate the corrected age, you need 2 pieces of information.

    1. What is the gestation of your baby at birth? (ex: 26 wk, 29 wk, 33 wk)⇨ this will give you how many wks early they are!
    2. How old is your baby now (in weeks or months)⇨ this Actual Age

    Every baby is given a due date of 40 wks. 

    So to calculate corrected age, there is 2 steps:

    1st Step: 40 wks Birth Gestation= _______(# of wks early they are) ⇦⚡THIS # NEVER CHANGES⚡

    2nd Step: Actual age (months or wks) – ______(# of wks early)= Corrected Age


    Example 1: Baby A is born 28 4/7 wks. He is currently 5 months old. What is the corrected age?

    1st Step: 40 wks 28 wks = 12 wks early ⇦⚡THIS # NEVER CHANGES for your baby

    2nd Step: 5 months(Actual Age) – 12 wks ( 3 months) = 2 months Corrected.

    ↪ ***Baby A should be acting and reaching the milestones of a 2 month old even though he is 5 month***

    Example 2: Baby B is born 25 6/7 wks. She is currently 7 months old. What is the corrected age?

    1st Step: 40 wks 25 wks = 15 wks early ⇦⚡THIS # NEVER CHANGES FOR YOUR BABY

    2nd Step: 7 months(Actual Age) – 15 wks ( 3.5 months) = 3.5 months Corrected.

    ↪ ***Baby B should be acting and reaching the milestones of a 3.5 month old even though she is 7 month***

    Example 3: Baby C is born at 30 2/7 wks on April 13. His due date is Jun 10.

    What is his corrected age in May? What is the corrected age in Sept?

    1st Step: 40 wks 30 wks = 10 wks early ⇦⚡THIS # NEVER CHANGES FOR YOUR BABY

    2nd Step: In May, the actual age is 1-month-old. There is NO corrected age because corrected age starts AFTER due date (after June)

    In Sept, he is 5 months(Actual Age) – 10 wks ( 2.5 months) = 2.5 months Corrected.

    What is a Premature Baby’s Corrected Age Used For?

    Corrected age is used to give the baby time to catch up with their milestones.

    It’s also used to assess if a baby is reaching milestones or not.

    Sunnybrook Medical Clinic offers a great resource on developmental activities that can be used in the 1st year of life.

    Vaccination: By Corrected or Actual Age?

    For vaccinations, I have seen doctors have different opinions.

    But most doctors I work with and have seen advised to vaccinate using actual age. 

    This is because the baby is out of the hospital by their actual age (ie. 2-5 month) and exposed to the outside world.

    So they need the protection of the vaccine.

    For example, my son received this 2 month vaccine when he was corrected 1 wk old.

    And he did well!!

    I chose to do this because he was already being exposed to family members and other kids.

    But if you are not comfortable vaccinating at actual age, you can definitely wait too.

    It’s your choice and you know what’s best for your baby!

    Talk to your doctor and get their opinion as well.

    When to Start Solid Food

    It’s recommended to start solids between 4-6 months corrected age.

    This is a guideline, so make sure your baby is showing signs they are ready before starting solids.

    This includes:

    • able to hold their head up on their own
    • sitting up by themselves
    • showing interest in your food

    Just remember not to push your baby and wait until they are ready.

    I will be doing a whole blog post about eating solids for preemies, tips and the best items you need to be successful.

    So stay tuned!

    Do Premature Babies Reach Milestones Later?

    Yes, premature babies are usually behind in their development and reach their milestones later.

    Therefore, it is important to monitor if your baby is reaching their milestones at least by their corrected age.

    Some preemies are fast learners and they reach milestones earlier than their corrected age too.

    Eventually, preemies do catch up.

    But there are many cases where an ex- preemie baby is very delayed and they are not reaching their milestones at all.

    This includes speech is delayed, they are not sitting up or crawling, not walking yet, not eating well.

    This is important to catch as a parent because your baby might need extra support and interventions such as speech therapy, physio, occupational therapy, feeding assessment.

    Early intervention is very important for any baby to be successful.

    Great apps parents can use to do developmental appropriate activities with their little one is Baby Sparks or Kinedu.

    Both Baby Sparks and Kinedu are great for preemies because they adjust their activities to match the corrected age.

    Below are screen shot of both Baby Spark and Kinedu app for when my son was 3 month (corrected 1 month).

    We really enjoy using these apps and the activities are really fun to do.

    Corrected age showing on Baby sparks app
    Corrected age showing on kinedu app

    Final Thoughts on Corrected Age vs Actual Age

    As a mom to a preemie, I was worried my son would never catch up and he would always be behind.

    But with time and speech therapy, he did catch up and he is doing well.

    Don’t stress yourself with reaching every milestone at a specific time.

    Some kids are just slower then others and need time.

    Just monitor and try to do developmental appropriate activities with your child to strengthen their skills.

    Also, please don’t compare your child with another child!!

    I used to do this and it would always stress me out because my son was always behind.

    Your child is special and they will meet their milestones when they are ready.

    Just be patience and enjoy the small moments.

    If you have any questions, feel free to contact me or send a message to @nicunursefaith on Instagram.

    Did this blog post clarify your confusion on Corrected age?


    If anything on my blog has helped you, please make sure to share the post, comment below the post and subscribe to my email list for more goodies.

    I would love to hear from you!

    Related Articles on Corrected Age

    Beginners Guide: How to Care for your Premature Baby

    Corrected age for a premature baby

    Corrected Age vs Actual Age: What is it and Why is Important for Preemies

    Sharing is caring!

    Leave a Comment

    Your email address will not be published. Required fields are marked *