Hearts Baby Blanket is just right for carseats and baby carriers.
It is comprised of hearts and cables.

I used Knit Picks Sport Shine yarn in Blush, 60% Pima Cotton 40% Modal natural beach wood fiber and is super soft.

5 balls
Needle size 6, 4.0 mm
Gage is 18 sts = 4”

Be sure to make a gage swatch. If your gage is a little different I have included the formulas to calculate your blanket width.