Weight. Average gain of 1 pound each month. Boys usually weigh about ½ pound more than girls. Generally, expect 2 times the birth weight by 4 to 5 months and 3 times the birth weight by 1 year.

Height. Average growth of about ½ inch each month.

Head size. Average growth of about ¼ inch each month.

Gets into a sitting position by themselves

Sits without support

Reaches for and grasps objects using fingers

Can move an object from one hand to another

Plays peek-a-boo

Starts teething, often starting with the two center front teeth in the lower jaw, then the two center front teeth in the upper jaw

Puts everything into mouth

Naps are often twice, sometimes 3 times a day, for 1 to 2 hours each (on average)

May start to wake up during the night and cry

Makes a lot of different sounds like "mamamama" and "babababa" (ma-ma, da-da)

Smiles or laughs when you play peek-a-boo

Lifts arms up to be picked up

Looks for objects when out of sight

Bangs two things together

Is shy, clingy, or fearful around strangers

Shows several facial expressions, like happy, sad, angry, and surprised

Looks when you call their name

Reacts when you leave (looks, reaches for you, or cries)

Give your baby safe toys that make noises when shaken or hit.

Play in front of a mirror, calling your baby by name and pointing to your baby's reflection in the mirror.

When talking to your baby, pause and wait for them to respond just as when talking with an adult.

Play pat-a-cake and peek-a-boo.

Name common objects when shown to your baby.

Make different sounds with your mouth and tone of voice.

Repeat and expand the sounds your baby makes, such as "ma-ma" when they say "ma."

Show picture books and read stories to your baby every day.

Give your baby toys with objects or knobs to push, poke, or turn.

Give your baby toys that stack or nest and show them how they work.

Build a tower with your baby and show them how to knock it down.

Create a routine for bath and bedtime.

Offer a cup.