The top pick for turning a CBD to THC ratio into an actual dose is the ratio-first milligram method: read total CBD and total THC off the label, convert them to milligrams per milliliter or per serving, then solve for the volume or piece count that lands on your target THC amount. It beats every app and chart on four criteria: it works with any product label, it survives the rounding that marketing ratios hide, it lets you hold THC steady while you raise or lower CBD, and it produces one number you can write down and repeat.
cannabis tincture dosage calculator
The ratio is a proportion, not a dose
A 20:1 label means 20 parts CBD for every 1 part THC. It says nothing about how much you take. A 30 mL bottle with 900 mg CBD and 30 mg THC is 30:1, and so is a 10 mL bottle with 300 mg CBD and 10 mg THC. Same ratio, different strength. That gap is why a calculator that only asks for the ratio will steer you wrong.
How to Calculate THC per Serving in Homemade Edibles
Option 1: Ratio-first milligram calculator (top pick)
This is the arithmetic version of a dosing calculator, and you can run it on a phone calculator in under a minute.
cannabis dosing calculator by gram
Pros
- Works on tinctures, capsules, gummies, and topicals with a stated milligram count
- Separates the ratio question from the strength question
- Lets you scale CBD up while keeping the THC number fixed
- No app, account, or subscription
Cons
- Requires an accurate label, and hemp and dispensary labels differ in how much they disclose
- Does not account for how much THC you actually absorb by a given route
- Assumes the product is mixed evenly, which matters for homemade edibles
Option 2: Per-serving label calculator
Packaged edibles usually list milligrams per piece or per package. Divide total THC by the number of servings, then divide your target dose by that per-piece number to get a fraction of a piece.
Pros
- Fast when servings are clearly marked
- Good for splitting a package across several sessions
- Makes low-dose THC practical without a scale
Cons
- Cutting a gummy rarely gives an even split
- Labeled THC can differ from tested THC
- Edible onset is slow, so it rewards patience more than precision
Option 3: A titration log
Numbers only help if you record what happened. A simple log with date, product, ratio, milligrams of CBD, milligrams of THC, time, and effect turns a one-time calculation into a personal dose curve.
Pros
- Shows your own pattern instead of a generic chart
- Exposes products that hit harder than their label suggests
- Useful when you switch ratios and need a reference point
Cons
- Takes consistency for a week or two before it says anything
- Self-reported effect is subjective
How to run the calculation
- Write down total CBD mg and total THC mg from the package.
- Divide CBD by THC to confirm the real ratio.
- Find total volume in mL, or total servings.
- Divide each cannabinoid by that number to get mg per mL or mg per piece.
- Divide your target THC dose by the mg of THC per unit. That gives the volume or piece count.
- Round down, never up.
- Log the result and the effect.
Example: a 30 mL tincture with 900 mg CBD and 30 mg THC gives 30 mg CBD and 1 mg THC per mL. A 2 mg THC target means 2 mL, which also delivers 60 mg CBD. If you want more CBD without more THC, the fix is a higher ratio product, not a bigger pour.
Where these calculators break down
Milligram math is exact and biology is not. Absorption varies by route, edibles can take an hour or more to show themselves, and CBD can interfere with the enzymes that clear THC, which may make a THC dose feel stronger than the label predicts. Trace THC in hemp products is often listed as a limit rather than a measured amount. Tolerance, body weight, liver function, and what you ate all shift the result. A calculator produces a starting point, not a promise.
Which approach fits your situation
If you use a tincture and want a repeatable daytime dose, use the ratio-first milligram method and measure with the dropper rather than counting drops. If you split packaged edibles, use the per-serving method and cut carefully. If you are moving your THC dose up or down over weeks, keep the log. Most people end up using all three, with the milligram math as the base and the log as the feedback loop. Start lower than you think you need, change one variable at a time, and talk with a clinician if you take prescription medications or have liver concerns.