What this is for: Body-surface-area dosing (Mosteller + Du Bois), species dose conversion with the FDA Km table, and power-law allometric scaling.
The formula: HED (mg/kg) = animal dose (mg/kg) × (animal Km ÷ human Km); allometry: Y2 = Y1 × (W2/W1)^b
How to use:
- In the BSA section, enter height and weight and read the Mosteller and Du Bois BSA values.
- Enter the dose rate in mg/m² and the stock concentration to get the total dose and the volume to draw.
- In Km Species Conversion, choose the from- and to-species, enter the dose in the from-species and the target body weight, and read the converted mg/kg dose and total dose.
- In Allometric Scaling, enter the quantity in species 1, both weights and the exponent b to get the scaled quantity.
- Enter a per-kg dose in species 1 in the same section to get the scaled per-kg dose in species 2.
BSA & Km — Body Surface Area and Dose from BSA
BSA by Mosteller and Du Bois, then a mg/m² dose to a total dose and a volume from stock.
cm
kg
mg/m²
mg/mL
BSA — Mosteller sqrt(H × W / 3600) (m²)
BSA — Du Bois (m²)
Total dose (mg) — uses Mosteller BSA
Volume to draw (mL)
Km Species Conversion (FDA table)
Human-equivalent dose (mg/kg) = animal dose (mg/kg) × Km animal / Km human. Species are picked from the workbook's FDA 2005 Km table.
| Species | Reference weight (kg) | BSA (m²) | Km |
|---|---|---|---|
| Human | 60 | 1.62 | 37 |
| Mouse | 0.02 | 0.007 | 3 |
| Hamster | 0.08 | 0.02 | 5 |
| Rat | 0.15 | 0.025 | 6 |
| Guinea pig | 0.4 | 0.05 | 8 |
| Rabbit | 1.8 | 0.15 | 12 |
| Monkey (rhesus) | 3 | 0.24 | 12 |
| Dog | 10 | 0.5 | 20 |
| Baboon | 12 | 0.6 | 20 |
| Mini-pig | 20 | 0.74 | 27 |
mg/kg
kg
Km (from)
Km (to)
CONVERTED DOSE (mg/kg)
Same dose in mg/m² (= mg/kg × Km from)
Total dose at target weight (mg)
Allometric Scaling — Power Law Between Species
A physiological quantity Y scales as Y = a × W^b: clearance and metabolic rate often use b = 0.75, volumes b = 1.0, times (half-life) b = 0.25.
kg
kg
mg/kg
Weight ratio W2/W1
SCALED QUANTITY in species 2
Dose in species 2 (mg/kg)
Prefer to work offline or keep a copy? The download link is right below.
Download the BSA & Allometric Dosing workbook (.xlsx)
Download the BSA & Allometric Dosing workbook (.xlsx)
Notes & limits (from the workbook): Km conversion (dose scales with surface area) is the FDA-recommended first step for a first-in-human starting dose — a safety factor (usually /10) is then applied on top, which is a judgement call and deliberately not built in. The Km method and the power law are different models: for the same rat dose the Km sheet gives 8.1 mg/kg while b = 0.75 gives 12.2 mg/kg. For study design report both and state the assumption; for first-in-human doses the FDA Km method is the regulatory default.