BSA Worked Examples: Adult, Pediatric, and Larger Body Sizes
Bikash Roy
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Bikash personally verifies every calculator against official standards (WHO, NIH, government data). Online research specialist, SEO strategist, and web developer with 10+ years building accurate digital tools.
Full bio →Seeing the Formula Spread Directly
The clearest way to understand how Mosteller, DuBois, and Haycock relate to each other is to run the same body size through all three and compare. These five examples, calculated with the exact formulas behind the BSA calculator, range from a small infant to a larger adult.
Example 1 — Average Adult (170 cm, 70 kg)
| Formula | Result |
|---|---|
| Mosteller | 1.818 m² |
| DuBois & DuBois | 1.810 m² |
| Haycock | 1.826 m² |
Spread: about 0.9% between highest and lowest. This is the typical case where formula choice barely matters.
Example 2 — School-Age Child (150 cm, 25 kg)
| Formula | Result |
|---|---|
| Mosteller | 1.021 m² |
| DuBois & DuBois | 1.067 m² |
| Haycock | 0.999 m² |
Spread: about 6.4%. This is meaningfully wider than the adult example — see BSA for pediatric dosing for why Haycock is often specifically preferred at this size range.
Example 3 — Larger Adult (190 cm, 110 kg)
| Formula | Result |
|---|---|
| Mosteller | 2.409 m² |
| DuBois & DuBois | 2.377 m² |
| Haycock | 2.433 m² |
Spread: about 2.3%. Notably, this example crosses the commonly cited 2.0-2.2 m² BSA capping threshold used at some institutions — exactly the size range where formula choice can matter for a capping decision. See how BSA is used for chemotherapy dosing for how capping works.
Example 4 — Infant (60 cm, 4 kg)
| Formula | Result |
|---|---|
| Mosteller | 0.258 m² |
| DuBois & DuBois | 0.252 m² |
| Haycock | 0.259 m² |
Spread: about 2.7%. Note that formulas validated primarily on older children and adults — like DuBois — carry more uncertainty at this size range; pediatric literature indexed by NIH’s PubMed Central often points to specialized neonatal formulas for this population rather than the three general-purpose formulas here.
Example 5 — Young Child (100 cm, 15 kg)
| Formula | Result |
|---|---|
| Mosteller | 0.645 m² |
| DuBois & DuBois | 0.640 m² |
| Haycock | 0.646 m² |
Spread: about 0.9%. Interestingly, the spread narrows again at this size compared to Example 2 — a reminder that formula divergence doesn’t move in a single consistent direction as body size changes; it depends on the specific height-to-weight proportions of each case.
The Pattern Across All Five Examples
Formula spread is smallest (under 1%) for proportionally average body sizes, regardless of whether that’s an adult or a child, and widest for body sizes with less typical height-to-weight ratios. This is why comparing all three formulas side by side — rather than trusting a single default — is useful specifically for cases far from average proportions, which is exactly what the BSA calculator shows automatically for any height and weight you enter.
Calculate Your Own
Run your own (or your child’s) height and weight through the BSA calculator to see all three formulas calculated instantly, and check common BSA calculation mistakes if a result looks different from what you expected.