Cannabutter Calculator
This free cannabutter calculator finds exact THC and CBD milligrams per teaspoon for any cannabis-to-butter ratio. Built-in decarb efficiency for oven, sous vide, Instant Pot, Ardent FX, and air fryer.
The Cannabutter Math
Cannabutter 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 butter you infuse it into. The formula:
(grams × THC% ÷ 100 × 1000 × decarb efficiency) ÷ teaspoons of butter = mg THC per teaspoon
The decarb efficiency is the part most calculators get wrong. Different methods convert THCA to THC at different rates: oven decarb hits ~90%, sous vide reaches ~95%, an Ardent FX gets 98%. If you skip decarb entirely, your raw flower stays as THCA — which has minimal psychoactive effect when eaten. For the full breakdown see our decarboxylation guide.
Standard Cannabis-to-Butter Ratios
Per cup (2 sticks / 8 oz) of butter, 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.
Most Common Mistakes
- Skipping decarb. Raw flower in butter gives you very mild butter. Decarb first.
- Cooking too long or too hot. Past about 4 hours or above 200°F, THC starts degrading into CBN (sedating, less psychoactive).
- Not straining well. Plant matter left in butter tastes grassy and adds nothing to potency.
- Using salted butter without accounting for it. Fine for savory recipes, but it changes baked goods.
How to Use This Cannabutter Calculator
This cannabutter calculator tells you exactly how strong your infused butter is — in milligrams of THC per teaspoon — for any amount of cannabis and any volume of butter. Enter four things: the amount of cannabis, its THC% (from the dispensary label), the butter 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 butter the recipe uses, then divide by the number of pieces.
Worked Example: Dose Per Cookie
Infuse 7 g of 20% THC flower (oven-decarbed, 90%) into 1 cup of butter, then bake 24 cookies using the whole cup:
- Butter 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 24 cookies: 1,260 ÷ 24 = ~52 mg THC per cookie
That is a strong cookie. For ~10 mg pieces, use 3.5 g of flower instead of 7 g, or split the batch into more pieces. Adjust the inputs above to design the exact per-piece dose you want.
Cannabutter Potency by Strain THC%
Stronger flower makes stronger butter, and the relationship is linear. Using 7 g into 1 cup of butter, oven-decarbed:
| Flower THC% | Approx mg THC / tsp |
|---|---|
| 15% | ~20 mg |
| 20% | ~26 mg |
| 25% | ~33 mg |
| 30% | ~39 mg |
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 butter: 1 cup = 2 sticks = 8 oz = 16 tablespoons = 48 teaspoons.
How to Store Cannabutter
Cannabutter keeps about 2 weeks in the refrigerator in an airtight container, or 6 months or more in the freezer. Freeze it in a silicone ice-cube tray or rolled in parchment so you can portion it without thawing the whole batch. Light and heat degrade THC over time, so store it dark and cold, and label it clearly with the mg-per-teaspoon you calculated. Keep it away from anyone — and any pet — who should not eat it.