Adjusted Age Calculator

Calculate the precise age of your premature baby with the following tool.

Created by Helen Stark
Helen Stark
Helen Stark

Student of Harvard university, she loves to observe new things about society, she studies Wikipedia more and learns about quantum physics on the internet. She loves dancing and singing songs.

Full Bio

Reviewed by Nick Walker
Nick Walker
Nick Walker

Done PHD of nuclear physics from the University of Pennsylvania. He is always seeking ways to explain science in easy terms. Moreover, he loves coffee & its beans more than his girlfriend (not at all).

Full Bio

Based on Research: 


The birth of a premature baby brings a lot of new challenges. One of the biggest necessities is to understand the development and growth. That's where our adjusted age calculator helps.

With the help of this tool, you can effortlessly determine the chronological age, and corrected age of a newborn baby. Our calculator is based on the fact that it only provides calculations for babies born preterm (between the 21st & 37th week of gestational age).

What Is The Adjusted Age?

This is the actual age of your baby who is born before the 37th week of gestation. It's an adjustment for the time that is spent in the womb. The adjusted age allows the physicians to assess the development of the child by considering their preterm delivery date. 

What Is The Difference Between Corrected Age And Real Age?

The chronological age is the time duration, measured in years, months, and days from the birth to the current date. It is also called actual age while the corrected age is measured by subtracting the number of weeks the infant was born before the expected due date from the chronological age. 

What Is Considered A Premature Pregnancy?

When the babies are born before 37 weeks of pregnancy they are considered premature. And this adjusted age calculator is particularly developed to tell you the corrected age of a premature baby based on his/her chronological age. There are different types of preterm birth, categorized by how early or late the baby is born. Here they are:

  • If the body is born less than 28 weeks then it is extremely preterm
  • When the baby is born from 28 to less than 32 weeks then it is considered very preterm 
  • If it happens between 32 to 27 weeks then it is Moderate To Late preterm

How To Calculate The Preemie Adjusted Age?

To calculate the adjusted age of the child, subtract the gestational age of the child from 40 weeks. For a precise calculation, follow these steps:

  1. Write down the number of days your baby was born before the expected due date. You can do that in two ways:
  • Determine the difference between the actual birth and due date of the baby
  • Find the difference between the gestational age of the baby and the full-term gestational age (280 days)
  1. Calculate the difference between the number of days early and your baby's current age in days.


Suppose the current date is 13 Feb 2024 the birthdate of your baby was 1 Feb 2024, and the gestational age of the baby is 35 weeks, and now how to calculate the chronological age, 18-month Adjusted Age, and 22-month Adjusted Age..!


Given that:

Current date = Feb 13, 2024

Birth date = Feb 1, 2024

Gestational Age at Birth = 35 weeks

Chronological Age:

Chronological age = Current date - Birth date

Chronological age = Feb 13, 2024 - Feb 1, 2024 = 12 days

Days Needed To Reach Corrected Birthdate:

Prematurity in days= (40 weeks - 35 weeks) * 7 days/week = 35 days

Days needed to reach corrected birthdate = 35 days - 12 days (current age) = 23 days

Adjusted 18 Months: 

18-months = 547.501 days

Total days to reach 18-month adjusted age: 547.501 days + adjusted age + chronological age

Total days to reach 18-month adjusted age = 547.501 + 23 + 12 = 582.501 days 

Adjusted 18 months = Feb 2, 2024 + 582.501 = Sept 06, 2025

Adjusted 22 Months: 

22-months = 669.167 days

Total days to reach 22-month adjusted age: 669.167 days + adjusted age + chronological age

Total days to reach 22-month adjusted age = 669.167 + 23 + 12 = 704.167 days 

Adjusted 22-months = Feb 2, 2024 + 704.167 = January 06, 2026

Skip the hassle of manual calculations, and try our adjusted age calculator. Get precise chronological and corrected age values for your newborn in seconds.

These manual calculations might be tricky and include human error. This is why for instant and precise guess, enter the premature delivery data in the adjusted age calculator and get the corrected age for up to 18 & 22 months.


Is The Adjusted Age The Same As Corrected Age?

Yes, They both refer to the age of a premature or preterm infant, adjusted for the number of weeks/days born before the expected due date.

Do You Use Corrected Age For Baby Born At 37 Weeks?

The babies that are born at 32–37 weeks of pregnancy lie on the preterm chart until 2 weeks past their estimated due date. After that, they are considered on the main charts with the help of the corrected age measure based on the due date.

How Can You Tell If Baby Will Come Early?

If you are experiencing any of the following signs or symptoms 37 th week of pregnancy:

  • Preterm Labor
  • Experiencing changes in your vaginal discharge (watery, mucus, or bloody)
  • The increased amount of vaginal discharge
  • Feeling a high pressure in your pelvis or lower belly, like the baby is pushing down
  • Constant low, dull backache

At What Age Do You Stop Using Adjusted Age?

When a child reaches 24 months chronological age, there is no need to correct the age for prematurity.