Formula Comparison
Mifflin-St Jeor vs Harris-Benedict
Both estimate your resting calorie burn, but they were built decades apart and rarely agree. Compare them side by side for your own stats below, then see which to trust.
The short answer
Use Mifflin-St Jeor. It is newer (1990), built on a broader modern population, and a 2005 systematic review found it the most accurate of the common resting-metabolism equations — which is why the Academy of Nutrition and Dietetics recommends it.
The two formulas side by side
| Mifflin-St Jeor | Harris-Benedict (rev. 1984) | |
|---|---|---|
| Published | 1990 | 1919, revised 1984 |
| Derived from | 498 adults (251 M / 247 W), aged 19–78, normal weight to obese | 239 adults (136 M / 103 W), aged 16–63 |
| Men (kcal/day) | (10 × kg) + (6.25 × cm) − (5 × age) + 5 | 88.362 + (13.397 × kg) + (4.799 × cm) − (5.677 × age) |
| Women (kcal/day) | (10 × kg) + (6.25 × cm) − (5 × age) − 161 | 447.593 + (9.247 × kg) + (3.098 × cm) − (4.330 × age) |
| Recommended by | Academy of Nutrition and Dietetics | — |
Why they differ
The Harris-Benedict equation was first published in 1919, built from 239 adults — 136 men and 103 women (about 43% female), aged 16 to 63 — a lean, early-20th-century sample whose body composition differs from today's heavier population. Even after its 1984 revision by Roza and Shizgal, modern validation studies find it tends to overestimate resting calorie burn, particularly in people with obesity, so it usually returns a higher number than Mifflin-St Jeor for the same inputs. The Mifflin-St Jeor team set out to fix exactly that, deriving their equation from measurements on 498 healthy adults across a wide range of ages and body sizes. In our 840-profile study, Harris-Benedict read higher in 81% of cases. There is more on its origins in the equation explained.
Common questions
Which is more accurate, Mifflin-St Jeor or Harris-Benedict?
Mifflin-St Jeor. A 2005 systematic review found it predicted measured resting metabolism within 10% for more people than the Harris-Benedict equation, across both non-obese and obese adults, and it had the narrowest error range.
Why does Harris-Benedict give a higher number?
The original Harris-Benedict equation dates from 1919 and was built on a lean, early-20th-century sample. In modern validation studies it tends to overestimate resting calorie burn — especially in people with obesity — so it usually reads higher than Mifflin-St Jeor for the same person.
Which formula should I use?
Mifflin-St Jeor for most people — it is the current default in clinical practice. Harris-Benedict is mainly of historical interest now, useful mostly for seeing how estimates have changed over time.