A dose is a single measured amount you take; dosage is the wider plan of how much and how often to take it. So you take one dose every eight hours, and that pattern together is your dosage.
The core difference
Dose is the single amount taken at one time, while dosage is the size and frequency of doses over a course of treatment.
- dose — a measured amount of medicine taken at one time: take one dose every eight hours with food.
- dosage — the size and frequency of doses given to a patient: the doctor increased her dosage after the first prescription proved too mild.
How to tell them apart
A useful trick is to swap in the word "plan": dosage is the plan (how much, how often, for how long), while a dose is just one instalment of that plan. If you can point to a single tablet or spoonful, you are talking about a dose; if you are describing the schedule across days or weeks, you mean the dosage.
The confusion usually surfaces on medicine labels and in conversations with a pharmacist, where people ask about "the dose" when they actually mean the ongoing dosage, or vice versa. Getting it right matters for clarity when checking instructions, especially for a child or pet, where the correct amount depends on weight.
