Tylenol dosage

Daelyn • Happily married and mama to Finn Charlton + Ellis Jameson👦🏼👶🏼💕
What is the Tylenol/Weight ratio? My son is just under 20lbs. How much of the liquid Tylenol should I be giving him?? I've only been 1.25 and I know that's not enough to work for him!