Medical Marijuana Dosage Calculator
Estimates an initial medical marijuana dosage (THC/CBD in mg) based on body weight, condition severity, tolerance, and administration method. Always consult a licensed healthcare provider before use.
Formula
Step 1 — Base Effective Dose (mg):
Base Dose = (Severity Factor × Weightkg) × Tolerance Multiplier
• Severity Factors: Mild = 0.05 mg/kg, Moderate = 0.10 mg/kg, Severe = 0.20 mg/kg
• Tolerance Multipliers: Naïve = 1.0×, Low = 1.5×, Moderate = 2.5×, High = 4.0×
Step 2 — Administered Dose (accounting for bioavailability):
Administered Dose (mg) = Base Effective Dose ÷ Bioavailability
• Oral ≈ 12%, Sublingual ≈ 25%, Inhaled ≈ 40%, Topical ≈ 3%
Step 3 — THC / CBD Split:
THC Dose = Administered Dose × THC Fraction
CBD Dose = Administered Dose × CBD Fraction
• THC-Dominant (20:1): THC = 20/21, CBD = 1/21
• Balanced (1:1): THC = 1/2, CBD = 1/2
• CBD-Dominant (1:20): THC = 1/21, CBD = 20/21
Assumptions & References
- Base dosing range (0.05–0.20 mg/kg) derived from clinical micro-dosing guidelines and the principle of "Start Low, Go Slow" endorsed by Health Canada and state medical boards.
- Bioavailability estimates: Oral 6–20% (mean 12%) — Grotenhermen, 2003, Clin Pharmacokinet; Sublingual 20–35%; Inhaled 30–56% (mean 40%) — Huestis, 2007, Chem Biodivers; Topical 1–5%.
- Tolerance multipliers are approximations based on receptor downregulation research (Hirvonen et al., 2012, Mol Psychiatry).
- THC:CBD ratios reflect common pharmaceutical and dispensary product categories; the entourage effect may modify individual response.
- This tool does not account for drug interactions, hepatic metabolism (CYP2C9/CYP3A4), pregnancy, pediatric use, or psychiatric contraindications.
- Not a substitute for professional medical advice. Legal status of medical marijuana varies by jurisdiction.