The primary unit of measure for cannabis products is grams. Flower comes in sizes 1 gram, 3.5 grams (one eighth ounce, or an eighth); 7 grams (one quarter ounce, or a quarter); 14 grams (one half ounce, or a half); and 28 grams (one ounce). A pound of weed is 16 ounces.
Concentrates are sold by the gram or half gram usually. Other sizes might include 2g, 2.5g, 3g, 3.5g.
Edibles contain THC and CBD in milligrams. Since they have a legal maximum amount, the total amount of a product is usually 100mg of THC, usually made in pieces that are each 10mg. For CBD, you might see 5-100mg, although there’s no limit for CBD.
Sometimes THC and CBD are present in an edible product in proportion to one another. For example, a 1:1 product has equal amounts of THC and CBD. A 4:1 product has four parts THC for every one part CBD. A 1:20 product has one part THC for every 20 parts CBD.
Flower contains THC and CBD in percentages, meaning the total percentage of the bud. Low THC products might be only 5% or 10% THC. The highest THC amounts are between 30% and 40%. CBD will be present at much lower amounts, only 1-6%.
Concentrates contain THC and CBD in percentages, often 70% or higher.