Difference Between Adult and Baby

We notice a huge difference between an adult and a baby in size and body parts. Other than this, there are so many differences in body functions between an adult and a baby.

They share the same body parts and uses. But the way each body part functions will differ in an adult and a baby.

They also share similar features but vary in numerous parameters.

Adult vs Baby

The main difference between an adult and a baby is that an adult has a big size in every body part. On the other hand, the baby has a very small size of every body part when compared to an adult. Another difference between an adult and a baby is dehydration. A baby can easily get dehydrated while an adult takes time to get dehydrated.

Adult vs Baby

The term “adult” has a wider meaning in terms of both science and legal concepts. In terms of science, an adult means a person who has attained a certain age called majority, 18 years old.

An adult signifies the changes happening in the body parts. An adult legally means a person who has attained 18 years and has the eligibility to vote.

The term “baby” means the younger or a smaller version of a human being. A baby is called an infant.

The body length of the baby is small. They weigh lesser and their body parts are relatively small.

A baby cannot speak till they reach a certain age. This age for speaking may vary for each baby.

Comparison Table Between Adult and Baby

Parameters of ComparisonAdultBaby
Body sizeThe body size of an adult is bigger when compared to a baby.The body size of a baby is quite small when compared to an adult.
DehydrationAdults usually take a long time to get dehydrated s compared to babies.Babies can easily get dehydrated than adults get.
Body temperatureAdults have a stable and mature body temperature.Babies have unstable and immature. body temperature
Heart ratesThe heart rates of adults are quite slower than babies.The heart rates of babies are quite faster than adults.
WeightAdults weigh heavier than babies.Babies weigh lesser than adults.

What is Adult?

An adult is a person who is fully grown and has reached sexual maturity. The word “adult” can be associated with both science and legal.

They can be used concerning numerous areas and has a wider meaning. The age of an adult is considered globally as 18.

The age of 18 is the age of maturity. Persons who are above 18 are entitled to voting rights.

In terms of science, an adult can be defined as a person whose body has reached maximum growth. For example, changes in voice for men, body hairs for both sexes, an increase in sizes of breasts for women, etc.

Usually, this puberty stage begins at around 11 years. This process of puberty gets completed by 16 or 17 years.

They undergo changes in their weight and height. However, in some cases, puberty may happen earlier or later.

In terms of legal and social, an adult can be defined as a person who is capable of performing responsibilities. They know about making their own decisions.

People who have completed 18 are entitled to vote and select the parties which should rule the country.

Hence, an adult means a grown person both mentally and physically. They transform and undergo changes to become an adult.

What is Baby?

A baby is an infant or a child recently born into the world and has aged only a little. The term “infant” is from the Latin word Infans.

The term “Infans” means the inability to speak. Generally, babies are unable to speak.

Once they reach a certain age, they start saying small words. Babies must be carefully handled as they are small and prone to diseases.

The term “babies” is very young children aged from months to 4 years. Children have a lesser blood flow in their bodies. They have a high risk of bleeding to death.

They take a longer time to heal from wounds or injuries. In addition to this, they have small airways that make the breathing process slow.

The length of their body is small. Babies weigh a lot lesser than an average human being.

Usually, a baby’s head is large in proportion to the size of their body. They won’t have teeth.

Hence, babies only drink milk through breastfeeding. Eventually, they start growing milk teeth and chew little solid foods.

Hence, a baby is a smaller version of an adult but has to be taken care of properly as they have the risk of getting diseases and other problems.

Main Differences Between Adult and Baby

  1. An adult is a fully grown and developed person while a baby is recently born into a world and in the process of growing.
  2. A baby’s head proportion to the body is larger than an adult’s head proportion to the body.
  3. A baby has faster heartbeats in comparison to the heartbeats of an adult
  4. Babies have less healing power and have a high risk of diseases than an adult.
  5. The airways of breathing are small in babies while adults have a wider airway for the breathing process.
  6. Dehydration can happen in a baby faster than it happens in an adult.
Difference Between Adult and Baby


Both an adult and a baby have similar body parts and ways of functioning body organs. They differ in size, weight, height, heart rates, respiratory rates, etc.

A baby does not have the ability to speak but an adult can speak without any difficulties. In short, a baby is a younger version of an adult.

Adult undergoes numerous changes of puberty.

The age of an adult is 18. The age of a baby is from months to 4 years.

A baby cannot have solid foods. An adult has better digestion and teeth to chew solid foods.

Eventually, a baby grows into an adult.


  1. https://www.sciencedirect.com/science/article/pii/S0165178110003574
  2. https://europepmc.org/article/med/6886334
Search for "Ask Any Difference" on Google. Rate this post!
[Total: 0]
One request?

I’ve put so much effort writing this blog post to provide value to you. It’ll be very helpful for me, if you consider sharing it on social media or with your friends/family. SHARING IS ♥️