Accurate Allometric Scaling for Pre-Clinical Research.
Stop using simple weight ratios. Calculate scientifically accurate dosage conversions between humans and laboratory animals using Body Surface Area (BSA) normalization and FDA-standardized $K_m$ factors.
🐭 Human to Animal Dose Calculator
Convert doses between species using FDA-approved Km factor allometric scaling method.
🤖 AI-Powered Allometric Scaling
Convert doses between species using FDA-approved Km factors with AI recommendations for species-specific considerations.
📋 Km Factor Reference Table
Based on FDA Guidance for Industry: Estimating the Maximum Safe Starting Dose in Initial Clinical Trials
| Species | Reference Weight (kg) | BSA (m²) | Km Factor |
|---|---|---|---|
| Human | 60 | 1.62 | 37 |
| Mouse | 0.02 | 0.007 | 3 |
| Rat | 0.15 | 0.025 | 6 |
| Hamster | 0.08 | 0.016 | 5 |
| Guinea Pig | 0.4 | 0.05 | 8 |
| Rabbit | 1.8 | 0.15 | 12 |
| Cat | 2 | 0.17 | 11.7 |
| Monkey (Rhesus) | 3 | 0.25 | 12 |
| Dog | 10 | 0.5 | 20 |
| Marmoset | 0.35 | 0.06 | 6 |
| Squirrel Monkey | 0.6 | 0.09 | 7 |
| Baboon | 12 | 0.6 | 20 |
| Micro Pig | 20 | 0.74 | 27 |
| Mini Pig | 40 | 1.14 | 35 |
The Science Behind the Tool
Why “mg/kg” Is Often Wrong
Small animals have faster metabolic rates than humans.1 Simply prescribing the same $mg/kg$ dose often leads to under-dosing in smaller species.
This tool uses the Allometric Scaling Method, the gold standard for translational medicine.
- Formula: Uses the exponent $0.67$ or $0.75$ for body surface area normalization.
- $K_m$ Factors: Automatically applies the correct correction factor (e.g., Human $K_m=37$, Rat $K_m=6$, Mouse $K_m=3$).
- Result: A dose that reflects the true metabolic clearance of the drug in the target species.
Core Capabilities
Essential for Drug Development & Veterinary Medicine
- 🔄 Bidirectional Conversion
- Human $\to$ Animal: Calculate the starting dose for animal studies based on human clinical data.
- Animal $\to$ Human: Convert NOAEL (No Observed Adverse Effect Level) from toxicity studies into a Maximum Recommended Starting Dose (MRSD) for Phase I human trials.
- 🐾 Multi-Species SupportPre-loaded with standard $K_m$ factors for:
- Mouse, Rat, Guinea Pig, Hamster
- Rabbit, Dog (Beagle), Cat
- Monkey (Cynomolgus/Rhesus), Marmoset
- Human (Adult & Child)
- 📝 Reference CitationsEvery calculation is based on the FDA Guidance for Industry (2005): “Estimating the Maximum Safe Starting Dose in Initial Clinical Trials for Therapeutics in Adult Healthy Volunteers.”
Use Cases
Who Needs This Tool?
- Pre-Clinical Researchers: determining the initial range for efficacy studies in rodents.
- Veterinarians: Calculating off-label doses of human medications for exotic pets or companion animals where veterinary formularies are unavailable.
- Pharmacy Students: Understanding the principles of pharmacokinetics and interspecies scaling.
Understanding Human Equivalent Dose (HED)
The Role of Body Surface Area (BSA)
While body weight varies linearly, metabolic processes (like liver enzyme activity and renal clearance) correlate better with body surface area. Our animal dose calculator normalizes the dose to $mg/m^2$ rather than just $mg/kg$, ensuring that a mouse receives a proportionally higher dose per unit of weight to achieve the same systemic exposure as a human.
Safety Factors in Translation
When converting from animal toxicity data to humans, safety is paramount. Our tool allows you to view the raw HED and also provides an option to apply a safety margin (usually dividing by 10) to determine the safe starting dose for first-in-human trials.
Frequently Asked Questions
Allometric Scaling FAQ
Q: Can I use this for all drugs?
A: This method works best for small molecule drugs cleared renally or hepatically. It should not be used for monoclonal antibodies or proteins, which scale differently (often linearly by weight).
Q: Why is the mouse dose so much higher in mg/kg?
A: A mouse has a much higher metabolic rate than a human.2 To maintain the same drug concentration in the blood, the mouse often needs a dose (in mg/kg) that is 12x higher than the human dose.
Q: Does this account for individual differences?
A: No. This tool uses standard reference weights and BSA factors for the species. It is an estimation tool for starting doses, not a substitute for therapeutic drug monitoring.
Important Disclaimer
For Research and Educational Use Only
This tool provides theoretical calculations based on allometric scaling principles. It does not account for species-specific metabolic differences (e.g., glucuronidation defects in cats). Always consult peer-reviewed literature and a licensed veterinarian before administering any substance to an animal.
