💉 Body Surface Area (BSA) Veterinary Dosing Converter Simulator

Weight-to-BSA Conversion Formula

BSA scales with weight to the 0.67 power, not linearly.

• 0.67: Formula exponent (allometric power law)
• kg: Input unit (body weight)
• m²: Output unit (surface area)
• Oncology: Common use (chemo dosing)

Why a power law, not linear scaling

Surface area grows slower than mass as an animal gets larger.

Placeholder: small pets have proportionally more surface area per kg.

Species-Specific BSA Constant

The constant K adjusts the formula per species body shape.

• 10.1: Canine K (dogs)
• 10.0: Feline K (cats)
• 10.5: Equine K (horses)
• cm²/g^0.67: Units (scaled constant)

Choosing the right constant

Placeholder: constant reflects average body geometry per species.

Placeholder: wrong constant skews dose estimates.

BSA (m²) Calculation Result

The computed BSA value becomes the dosing reference point.

• ~0.3 m²: Small dog BSA (5 kg)
• ~0.7 m²: Medium dog BSA (20 kg)
• ~1.4 m²: Large dog BSA (50 kg)
• 3 decimals: Precision (clinical rounding)

Reading the BSA output

Placeholder: BSA result feeds directly into dose calculation.

Placeholder: always double-check units before dosing.

Chemo Dose (mg/m²) Application

Target dose per m² multiplies by BSA for total mg administered.

• 10-300 mg/m²: Typical range (protocol dependent)
• Dose × BSA: Formula (total mg)
• Nearest 0.1 mg: Rounding (syringe precision)
• Every visit: Recheck (weight changes)

From target dose to syringe

Placeholder: multiply mg/m² target by patient BSA for total dose.

Placeholder: recalculate BSA at every treatment visit.

Why BSA Dosing Differs From mg/kg

BSA tracks metabolic rate better than raw body weight.

• Overdose: mg/kg risk (small patients)
• Safer scaling: BSA benefit (across sizes)
• Oncology: Adopted by (human & vet)
• Extremes: Limitation (very small/large)

Metabolic scaling rationale

Placeholder: metabolic rate correlates with surface area, not mass.

Placeholder: BSA dosing reduces toxicity risk in small patients.