Answer first
A cannabis dosing calculator does one job: it multiplies body weight by a dose rate, then divides by product strength. A 70 kg adult at a 0.1 mg/kg rate gets 7 mg. A 30 mL bottle holding 1000 mg CBD holds 33 mg/mL, so 7 mg is about 0.2 mL. The arithmetic is exact. The dose rate is not. No US federal agency publishes a standard cannabis dose.
Is There a Calculator for Weed Dosage?
Inputs a calculator needs
- Body weight in kilograms or pounds.
- Target dose in mg, or a rate in mg/kg.
- Product strength: total mg per bottle, mg per mL, or mg per piece.
- Route: oral oil, capsule, edible, inhaled, topical.
- Tolerance and prior use.
Why route changes the number
Oral CBD bioavailability averages about 6% in published human data, with a range of 4% to 20% by formulation. Inhaled cannabinoids reach the bloodstream in minutes. Oral edibles peak at 2 to 4 hours. A calculator that ignores route returns a number with no context.
Weight-based formula
Dose (mg) = body weight (kg) × dose rate (mg/kg). The FDA label for Epidiolex, a prescription CBD product, starts at 2.5 mg/kg twice daily, or 5 mg/kg per day, and targets 10 mg/kg per day. For a 70 kg adult that is 350 mg per day at the starting rate. Over-the-counter CBD labels sit lower. Published consumer surveys report common use of 10 mg to 50 mg per day. That gap is the reason a calculator needs a stated source for its rate.
is there a calculator for weed dosage
Product strength math
- Divide total mg by bottle volume in mL. 1500 mg in 30 mL = 50 mg/mL.
- Divide mg/mL by 20 drops per mL. 50 mg/mL = 2.5 mg per drop.
- Divide the target dose by mg per drop. A 12 mg target needs about 5 drops.
Drop size varies by dropper. Measure 1 mL once and count the drops. Gummies and capsules skip this step because the label states mg per piece.
THC caps and serving limits
Canada limits edible cannabis to 10 mg THC per package. Colorado limits retail edible servings to 10 mg THC. A calculator built for THC should cap output at the local legal limit and flag any single serving that exceeds it.
Timing
Inhaled THC peaks in 15 to 30 minutes. Oral THC peaks at 2 to 4 hours and lasts 4 to 8 hours. CBD half-life runs 18 to 32 hours with repeated dosing. Dose changes should be spaced by at least a week so the prior dose clears.
What a calculator cannot do
It cannot read a lab report, check a drug interaction, or screen for liver disease. CBD inhibits CYP2C9, CYP2D6 and CYP3A4, the same enzymes that clear warfarin, clobazam and several statins. Epidiolex carries an FDA warning for liver injury. People who take prescription drugs, are pregnant, or have liver disease should set the calculator aside and talk to a clinician.