The correct dose of acetaminophen for your child is based on their weight, not their age. If you don't know how much your child weighs and they are too young to stand on a scale, weight yourself while holding them and then weigh yourself alone. Subtract your weight from the combined weight to get your child's weight. Do not give acetaminophen to a baby under 3 months of age without a doctor's approval. Shake liquid medicine well before measuring. Never give acetaminophen to a child who is taking other medicine that contains acetaminophen unless a doctor advises it. Infants' and children's liquid acetaminophen (both labeled 'oral suspension') have the same concentration: 160 mg per 5mL. The only difference is that the infant version comes with a syringe and the children's version comes with a cup. You can repeat the dose every 4 hours as needed. Do not give more than 5 doses in a 24-hour period.
A child weighing 6-11 pounds should receive a 1.25mL dose. A child weighing 12-17 pounds should receive a 2.5mL dose. A child weighing 18-23 pounds a 2.75mL dose. And 24-35 pounds a 5mL dose. Click here for chart.