LD50 Toxicology Safe Dose Calculator
Estimate the theoretical maximum safe human dose of a substance from rat LD50, body weight and a safety factor using standard allometric scaling.
How to Use the LD50 Toxicology Safe Dose Calculator
- Enter the published rat LD50 in mg/kg.
- Enter the human body weight in kg.
- Enter the safety factor (usually 100 or 1000).
- Click Calculate.
Cas d'utilisation
- •Teaching pharmacology and toxicology.
- •Order-of-magnitude chemical safety estimates.
- •Toxicology homework and exam prep.
Formule
Safe dose (mg) = LD50 (mg/kg, rat) × body weight (kg) / safety factor. The default 100× safety factor is a common regulatory starting point.
Questions fréquemment posées
Why 100 as a safety factor?
Regulators historically divide by 10 for interspecies differences and another 10 for inter-individual variability, giving the 100× default.
Is LD50 the same as a therapeutic dose?
No — LD50 is the lethal dose for 50% of test animals. Human safe exposure is usually orders of magnitude lower than the scaled LD50.
Medical disclaimer
Educational only. LD50 extrapolation is not a substitute for proper toxicological risk assessment or clinical judgement. Never use this calculator to justify exposure to any substance.