Leaf Finder
How to read a cannabis label and lab report
Start with three things: the terpene list (what it'll smell and tend to feel like), the THC:CBD balance, and for edibles, the mg of THC per serving. Then look for a QR code or batch number that links to the lab report, called a Certificate of Analysis (COA).
THC, THCa and "total THC"
Flower labels often show THCa, the form of THC in the raw plant, which turns into THC when heated. "Total THC" combines them using a standard formula: total THC = THC + (THCa × 0.877). Compare products by total THC, not THCa alone.
CBD and the ratio
A 1:1 product has about equal THC and CBD. CBD-dominant products (like 20:1) have very little THC. Many people find a balanced ratio feels gentler than THC alone. More on ratios.
Terpenes
Listed by amount, highest first, usually as a percentage or mg/g. The first one "leads." Total terpenes around 1–3% is common for flower. See the terpene guide.
Edibles and drinks: mg per serving
Check mg of THC per serving and servings per package. A 100 mg package of 10 pieces is 10 mg per piece. Common starting doses are 2.5–5 mg. Many beginners find 10 mg is a lot.
The lab report (COA)
Licensed products are tested by an independent lab. The COA shows the cannabinoid and terpene results for that batch, plus safety tests such as pesticides, heavy metals, microbials and residual solvents. Check that the batch number matches the package.
Leaf Finder can scan a label (and its QR code) and tell you if the product fits your match.
Scan a label with Leaf Finder →Common questions
What is total THC on a cannabis label?
Total THC combines THC and THCa (the form in raw flower that becomes THC when heated): total THC = THC + (THCa × 0.877).
What is a COA for cannabis?
A Certificate of Analysis is the independent lab report for a product batch. It lists cannabinoids, terpenes and safety test results such as pesticides and heavy metals.
How many mg of THC is a beginner dose?
Common starting doses for edibles are 2.5 to 5 mg of THC. Wait two hours before taking more.
For adults 21 and older where cannabis is legal. This is general information, not medical advice. Everyone responds differently: start low, go slow, and talk with a clinician about health conditions or medications. Terpene amounts vary by grower and batch, so check each product's label or lab report.