Cannabis Oil Calculator
This free cannabis oil calculator finds exact THC and CBD milligrams per teaspoon for any flower-to-oil ratio. Works with coconut oil, olive oil, MCT, and ghee, with built-in decarb efficiency for oven, sous vide, Instant Pot, Ardent FX, and air fryer.
The Cannabis Oil Math
Infused-oil potency comes down to four numbers: how much cannabis you start with, the THC percentage of that cannabis, how efficiently you decarb it, and the volume of oil you infuse it into. The formula is (grams × THC% ÷ 100 × 1000 × decarb efficiency) ÷ teaspoons of oil, which gives you milligrams of THC per teaspoon. Every number in that formula is something you control, which is why the ratio matters more than the technique. For the full breakdown of activation see our decarboxylation guide.
Standard Cannabis-to-Oil Ratios
Per cup of oil, with 20% THC flower oven-decarbed:
| Cannabis | Strength | Approx mg THC / tsp |
|---|---|---|
| 3.5g (⅛ oz) | Mild | ~13 mg |
| 7g (¼ oz) | Standard | ~26 mg |
| 14g (½ oz) | Strong | ~52 mg |
| 28g (1 oz) | Industrial | ~105 mg |
Numbers above assume 20% THC and oven decarb. Your strain and method will differ — use the calculator above for exact values.
How to Use This Cannabis Oil Calculator
This cannabis oil calculator tells you exactly how strong your infused oil is — in milligrams of THC per teaspoon — for any amount of cannabis and any volume of oil. Enter four things: the amount of cannabis, its THC% (from the dispensary label), the oil volume, and the decarb method you used. It handles the unit conversions and the decarboxylation efficiency loss for you, so you can dose a recipe accurately instead of guessing.
Once you know mg per teaspoon, dosing any recipe is simple: multiply mg per teaspoon by the teaspoons of oil the recipe uses, then divide by the number of pieces.
Worked Example: Dose Per Gummy
Infuse 7 g of 20% THC flower (oven-decarbed, 90%) into 1 cup of coconut oil, then portion the whole cup into 60 gummies:
- Oil potency: (7 × 0.20 × 1000 × 0.90) ÷ 48 tsp = ~26 mg THC per teaspoon
- One cup = 48 tsp, so the batch holds 48 × 26 = ~1,260 mg THC total
- Across 60 gummies: 1,260 ÷ 60 = ~21 mg THC per gummy
That is a strong gummy for most people. For ~10 mg pieces, use 3.5 g of flower instead of 7 g, or stretch the same oil across 120 gummies. Adjust the inputs above to design the exact per-piece dose you want.
Coconut Oil vs Olive Oil vs MCT
All three extract cannabinoids equally well because THC and CBD bind to any fat. The differences are practical rather than chemical:
- Coconut oil — highest saturated fat content, solid at room temperature, neutral flavor. The default choice for gummies and capsules.
- MCT oil — stays liquid, absorbs quickly, and is the standard base for tinctures and droppers.
- Olive oil — strong flavor that suits savory cooking and salad dressings, but it competes with sweet recipes.
- Ghee — clarified butter, so it behaves like butter in baking but tolerates higher heat without burning.
Because the math is identical across all of them, you can use this calculator for any of these and for cannabutter alike.
Converting Ounces to Grams
Cannabis is often sold by the ounce but dosed by the gram. Quick reference: 1 oz = 28 g, ½ oz = 14 g, ¼ oz = 7 g, ⅛ oz = 3.5 g. For oil: 1 cup = 8 fl oz = 16 tablespoons = 48 teaspoons.
How to Store Cannabis Oil
Infused oil keeps about 2 months in the refrigerator in an airtight jar, or 6 months or more in the freezer. Light, heat, and air all degrade THC over time, so use a dark glass container and fill it close to the top. Label it clearly with the mg-per-teaspoon you calculated, and keep it away from anyone — and any pet — who should not eat it.