Cannabis labels pack a lot of information into a small space, and most of it actually matters for your experience. The key details to focus on are the THC and CBD percentages, the terpene profile, the harvest or packaging date, and the batch number. Once you know what each section means, you can make much better purchasing decisions and avoid unpleasant surprises.
THC and CBD Percentages
The most prominent numbers on any cannabis label are the cannabinoid percentages, typically THC and CBD. For flower, these are listed as a percentage of the product’s total weight. A label reading 22% THC means that for every gram of flower, roughly 220 milligrams are THC. CBD is listed the same way, and some products carry significant amounts of both.
Here’s where it gets slightly tricky. Raw cannabis flower doesn’t actually contain much active THC. It contains THCA, a precursor that converts to THC when you apply heat (smoking, vaping, or baking). Labels account for this with a “Total THC” number calculated using a specific formula: Total THC = (THCA × 0.877) + THC. The 0.877 multiplier exists because not all THCA converts during heating. Some is lost. If your label lists both THCA and THC separately, the Total THC line is the number that predicts your actual experience.
For flower, anything under 10% THC is considered low potency, 10 to 20% is moderate, and above 20% is high. But potency alone doesn’t determine how a product will feel. Two strains at 25% THC can produce noticeably different effects depending on their terpene and minor cannabinoid profiles.
Edible Dosing: Milligrams Per Serving
Edibles use a completely different measurement system. Instead of percentages, they list THC in milligrams, both per serving and per package. Most U.S. states define a single serving as either 5 or 10 mg of THC. A package might contain 50 or 100 mg total, divided into individually marked servings. Canada takes a more conservative approach, capping entire packages at 10 mg.
This distinction between per-serving and per-package dosing is one of the most important things to check. A chocolate bar labeled “100 mg THC” with 10 servings means each piece contains 10 mg. Eating the whole bar delivers ten times a standard dose. Colorado requires each 10 mg serving to carry a universal THC symbol stamped directly into the product, making individual portions easier to identify even after you’ve opened the package.
If you’re new to edibles, 5 mg is a reasonable starting point. The effects take 30 minutes to two hours to set in, which is why the serving size on the label matters more than it does for almost any other cannabis product.
Terpene Profiles
Terpenes are aromatic compounds that give cannabis its smell and flavor, and they also influence its effects. Labels list them as a percentage of total weight for flower and concentrates, or in milligrams for edibles and infused products. Common ones you’ll see include myrcene (earthy, musky), limonene (citrus), linalool (floral), and caryophyllene (peppery).
A product with 2% total terpenes will generally have a more pronounced flavor and aroma than one at 0.5%. Some consumers use terpene profiles as a better predictor of effects than the indica/sativa label, which is largely a marketing distinction at this point. A strain high in myrcene tends to feel more sedating, while one dominant in limonene or pinene often feels more energizing. The terpene breakdown, when listed, gives you more useful information about what to expect than the strain name alone.
Concentrates: Potency and Purity
Concentrate labels follow similar principles but at much higher potency levels, often 60 to 90% THC. The format depends on the product type. Wax, shatter, and live resin typically list cannabinoids as percentages, while pre-filled vape cartridges may use either percentages or milligrams.
One thing unique to concentrate labels is residual solvent testing. Products made with solvents like butane, propane, or ethanol must be tested to confirm those chemicals have been removed to safe levels. You’ll usually see this as a simple “Pass” on the label, meaning the product fell within legal limits. In Massachusetts, for example, residual butane must test below 1 mg per kilogram of product. If a concentrate label doesn’t mention solvent testing at all, that’s a red flag.
For vape cartridges specifically, check the ingredient list. California requires all ingredients to be listed in descending order by weight, including any thinning agents or added flavorings. Some cartridges contain only cannabis-derived oil, while others include botanical terpenes or other additives. The ingredient list tells you exactly what you’re inhaling.
Harvest Date, Package Date, and Freshness
Most labels include either a harvest date, a packaging date, or both. This matters more than many consumers realize. THC degrades over time into CBN, a cannabinoid that produces groggier, more sedative effects. Heat, light, and oxygen all accelerate this process. Research published in Cannabis and Cannabinoid Research found that THC degradation is measurable even at room temperature, with CBN levels climbing as THC drops.
In practical terms, cannabis stored properly (cool, dark, sealed) holds its potency well for several months. But a product sitting on a dispensary shelf for six months or more may not deliver the experience its label promises. The THC percentage on the label reflects the product at the time of testing, not at the time you buy it. Checking the date and choosing fresher products, particularly for flower, gives you a better chance of getting what you’re paying for.
Warning Symbols and Required Icons
Legal cannabis packaging carries mandatory warning symbols that vary by state. The most widely adopted is the International Intoxicating Cannabinoid Product Symbol, or IICPS: a black cannabis leaf inside a yellow warning triangle. First adopted by Montana in 2022, it’s now used in some form across more than ten states including Oregon, New Jersey, Minnesota, and Vermont. The yellow triangle follows international caution sign standards (the same design logic behind biohazard or electrical warning symbols), and it contains no text, making it recognizable regardless of language.
Other states use their own symbols. Colorado, for instance, stamps a diamond-shaped “THC!” icon directly onto edible products. California requires a specific THC warning symbol on all packaging. Whatever the local design, these symbols serve one purpose: making it immediately obvious that a product contains intoxicating cannabinoids, especially important for edibles that might otherwise look like regular food.
Batch Numbers and Lab Testing
Every legal cannabis product carries a batch number or lot ID. This alphanumeric code tracks the product from cultivation through processing, testing, and sale. If a safety issue is discovered, the batch number is how regulators identify exactly which products are affected and need to be pulled from shelves.
For you as a consumer, the batch number also links to the lab test results. Many dispensaries and brands let you look up a batch number on their website or through a QR code on the packaging to see the full certificate of analysis. That document includes the exact cannabinoid percentages, terpene breakdown, and results for contaminant testing: pesticides, heavy metals, mold, and residual solvents. If a label seems vague or you want more detail than the packaging provides, the batch number is your key to the complete picture.
Strain Name and Product Type
The strain name (Blue Dream, OG Kush, Gelato) and the indica/sativa/hybrid classification are the most visible elements on most labels, but they’re also the least standardized. Two products labeled “Blue Dream” from different growers can have meaningfully different cannabinoid and terpene profiles. The strain name gives you a general neighborhood, not a precise address.
The product type designation (flower, pre-roll, live resin, distillate, rosin, full-spectrum, broad-spectrum) tells you more about what you’re actually getting. “Full-spectrum” means the product retains a range of cannabinoids and terpenes from the original plant. “Distillate” means it’s been refined down to mostly pure THC or CBD, with other compounds stripped away. “Live resin” or “live rosin” indicates the plant was frozen fresh before extraction, preserving more of the original terpene profile. These distinctions affect flavor, onset, and the overall character of the experience more than the strain name does.