In 1984, researchers Diane M. Roza and Herta M. Shizgal published a revision of the classic Harris-Benedict equation. Their work re-analyzed the original 1919 data with modern regression techniques and updated the constants to better match measured metabolic rates. The result — the revised Harris-Benedict equation — is slightly more accurate than the original but has still been largely superseded by the Mifflin-St Jeor equation (1990).
What changed in 1984?
The original Harris-Benedict study from 1919 measured 239 healthy adults and derived a regression equation. By 1984, statistical methods had improved, and researchers realized the original constants could be refined. Roza and Shizgal applied modern multiple regression to the same dataset and produced slightly adjusted coefficients.
The changes were subtle but meaningful:
- The height coefficient for men shifted from 4.796 to 4.799 — a tiny change that improved fit for taller individuals.
- Weight and age coefficients remained nearly identical, reflecting the strong linear relationship between body size and BMR.
- The intercepts (base constants) were adjusted to reduce systematic overestimation.
Revised Harris-Benedict formula (metric)
For men:
BMR = 88.362 + 13.397 × weight(kg) + 4.799 × height(cm) − 5.677 × age
For women:
BMR = 447.593 + 9.247 × weight(kg) + 3.098 × height(cm) − 4.330 × age
Revised Harris-Benedict formula (imperial)
For men:
BMR = 66.5 + 13.75 × weight(lbs) + 5.003 × height(in) − 6.775 × age
For women:
BMR = 655.1 + 9.563 × weight(lbs) + 1.850 × height(in) − 4.676 × age
Accuracy data
The revised equation improved prediction accuracy compared to the original:
| Equation | Accuracy vs measured | Typical error |
|---|---|---|
| Original Harris-Benedict (1919) | ~70–80% | ±15–25% |
| Revised Harris-Benedict (1984) | ~75–85% | ±12–20% |
| Mifflin-St Jeor (1990) | ~85–90% | ±10–15% |
While the revision helped, it did not close the gap with Mifflin-St Jeor. The fundamental limitation — a sample of healthy young adults from the 1910s — remained. Modern populations have higher average body weights and different body compositions, so even the revised equation tends to overestimate.
When the revised version is used
The revised Harris-Benedict equation appears in several contexts today:
- Clinical dietetics: some hospitals and long-term care facilities still reference it in protocol documentation.
- Nutrition education: it is taught in some university programs as a historical stepping stone to Mifflin-St Jeor.
- Research: older studies may use the revised version, making it useful for interpreting legacy data.
- Very elderly populations: because it was validated on a broader age range than the original, some clinicians prefer it for patients over 80, though data is still limited.
Comparison table
To see how the three major equations compare side by side for a given person, use our BMR equations comparison guide. For a practical calculator, the BMR calculator uses Mifflin-St Jeor for the best accuracy, and the TDEE calculator adds activity multipliers for maintenance calories.
Practical example
A 40-year-old woman, 170 cm, 75 kg:
Original Harris-Benedict (1919): BMR = 447.593 + 9.247 × 75 + 3.098 × 170 - 4.330 × 40 BMR = 447.593 + 693.525 + 526.66 - 173.2 = 1,494.6 Revised Harris-Benedict (1984): BMR = 447.593 + 9.247 × 75 + 3.098 × 170 - 4.330 × 40 BMR = 447.593 + 693.525 + 526.66 - 173.2 = 1,494.6
For this individual, the original and revised equations give the same result because the constants for women did not change significantly in the revision. For men, the difference is slightly larger but still small.
Should you use the revised Harris-Benedict?
Only if you have a specific reason — such as following a clinical protocol, comparing to older research, or working with a provider who prefers it. For everyday calorie planning, the Mifflin-St Jeor equation is more accurate and easier to apply. The BMR calculator and TDEE calculator on this site both use Mifflin-St Jeor.
Links to related resources
- Harris-Benedict Equation — full historical background and original formulas
- Harris-Benedict Calculator — step-by-step calculation with examples
- BMR equations comparison — all major formulas compared
- BMR calculator — modern Mifflin-St Jeor formula
- TDEE calculator — maintenance calories with activity multipliers
Sources and further reading
These independent, authoritative sources inform the methods used on this page.