TL;DR
- A 30-year-old male at 80 kg/178 cm needs 2,121 kcal/day sedentary and 3,358 kcal/day at athlete-level training. By age 60, the sedentary figure falls to 1,941 kcal — a 180 kcal/day reduction driven by the age term in the Mifflin-St Jeor formula.[1]
- A 30-year-old female at 65 kg/165 cm ranges from 1,644 kcal/day sedentary to 2,603 kcal/day at athlete level. By age 60, the sedentary figure falls to 1,464 kcal/day.
- Every number in these tables is deterministic physiology math computed from the Mifflin-St Jeor equation. Treat any estimate as a starting target with a ±10% error band, then verify against your actual weight trend over two to three weeks.[2]
Maintenance calories — the daily intake that holds body weight stable — are the anchor for any nutrition plan. This page is a computed reference: 50 cells across two standard profiles (male 80 kg/178 cm, female 65 kg/165 cm), five ages, and five activity levels, all derived from the Mifflin-St Jeor equation with standard activity multipliers.[1][3] Every value was computed at build time from the hub's open TDEE engine; none are hand-estimated from other sources.
How to read this table
Each table holds sex, body weight, and height constant so the only two variables you read are age (rows) and activity level (columns). Table 1 fixes male, 80 kg, 178 cm. Table 2 fixes female, 65 kg, 165 cm. If your own measurements differ, use the values as directional reads, or enter your exact numbers in the TDEE Calculator for a personalised result.
The five activity multipliers applied to BMR: sedentary ×1.20 (desk job, little or no exercise), lightly active ×1.375 (1–3 exercise days per week), moderately active ×1.55 (3–5 days per week), very active ×1.725 (hard exercise 6–7 days per week), athlete ×1.90 (twice-daily training or a physically demanding job plus structured training).[3]
Table 1: male, 80 kg, 178 cm — maintenance calories (kcal/day)
BMR at age 20 is 1,818 kcal/day, falling by roughly 50 kcal per decade to 1,618 kcal at age 60. The activity multiplier is a far larger lever than age: moving from sedentary to very active at age 30 adds 928 kcal/day, whereas ageing from 20 to 60 at a fixed activity level costs 240 kcal/day.
| Age | Sedentary | Lightly Active | Moderately Active | Very Active | Athlete |
|---|---|---|---|---|---|
| 20 | 2,181 | 2,499 | 2,817 | 3,135 | 3,453 |
| 30 | 2,121 | 2,430 | 2,740 | 3,049 | 3,358 |
| 40 | 2,061 | 2,362 | 2,662 | 2,963 | 3,263 |
| 50 | 2,001 | 2,293 | 2,585 | 2,876 | 3,168 |
| 60 | 1,941 | 2,224 | 2,507 | 2,790 | 3,073 |
Table 2: female, 65 kg, 165 cm — maintenance calories (kcal/day)
The Mifflin-St Jeor sex constant (−161 kcal for female vs. +5 kcal for male) produces a systematic gap of 350–550 kcal/day between the tables at matched ages and activity levels. This reflects average differences in lean mass, not a per-person rule — individual variation is large enough that the gap between a high-lean female and a low-lean male at the same age and weight can easily flip the direction.[4]
| Age | Sedentary | Lightly Active | Moderately Active | Very Active | Athlete |
|---|---|---|---|---|---|
| 20 | 1,704 | 1,953 | 2,201 | 2,450 | 2,698 |
| 30 | 1,644 | 1,884 | 2,124 | 2,364 | 2,603 |
| 40 | 1,584 | 1,815 | 2,046 | 2,277 | 2,508 |
| 50 | 1,524 | 1,747 | 1,969 | 2,191 | 2,413 |
| 60 | 1,464 | 1,678 | 1,891 | 2,105 | 2,318 |
The Mifflin-St Jeor formula and the activity multipliers
The formula: BMR (kcal/day) = 10 × weight (kg) + 6.25 × height (cm) − 5 × age (years) + sex constant (male +5, female −161).[1] For the reference male: 10 × 80 + 6.25 × 178 − 5 × 30 + 5 = 1,767.5 kcal at age 30, giving a moderately active TDEE of 1,768 × 1.55 = 2,740 kcal/day. TDEE = BMR × activity factor. The activity factors trace to FAO/WHO/UNU physical activity level categories.[3]
Why age matters less than you think
At every activity level, moving from sedentary to very active adds more calories than the entire age range in this table. For the reference male at age 30, sedentary maintenance is 2,121 kcal/day and very active maintenance is 3,049 kcal/day — a 928 kcal gap. The gap between age 20 sedentary (2,181) and age 60 sedentary (1,941) is 240 kcal. A 2021 analysis of doubly labelled water data from 6,421 people found that total energy expenditure is relatively stable from roughly ages 20 to 60 after controlling for body size — the apparent mid-life metabolic slowdown is largely a lean-mass effect, not a fundamental change in cellular metabolism.[4]
Using the reference for fat loss and muscle gain
Maintenance is the anchor; adjustments scale from it. A 500 kcal/day deficit targets roughly 0.45 kg of fat loss per week in energy-balance terms and is a rate the intervention literature supports for preserving lean mass in most populations. A 200–300 kcal/day surplus supports lean muscle gain at a pace that limits fat accumulation in a gaining phase. The TDEE Calculator generates personalised fat-loss, maintenance, and lean-bulk targets from your own inputs.
Activity level: the most common source of error
Most people overestimate their activity level. An office worker who trains three times per week is moderately active, not very active. If your weight is rising on a "maintenance" intake, the likely fix is dropping one activity tier — not a new formula. The 2003 Livingstone and Black review of energy-intake assessment errors found systematic overestimation of physical activity level is one of the most consistent biases in self-reported data.[5]
Frequently asked questions
How accurate is a Mifflin-St Jeor TDEE estimate?
For most healthy adults the Mifflin-St Jeor formula estimates resting metabolic rate within roughly ±10% of a measured result, making it the most accurate general-population equation available without lab equipment — it outperformed Harris-Benedict in the Frankenfield 2005 comparison that led the American Dietetic Association to recommend it.[2] The larger source of error is usually the activity multiplier: people overestimate how active they are. If your weight is not tracking as the table predicts, adjust intake rather than the formula.
Why do TDEE values drop with age in this table?
The Mifflin-St Jeor formula subtracts 5 kcal per year of age, so BMR falls by roughly 50 kcal per decade between ages 20 and 60.[1] A 2021 analysis of doubly labelled water data from 6,421 people found that organ-level metabolic rates are more stable across midlife than previously assumed — the apparent slowdown is largely explained by lean-mass loss rather than a per-cell reduction — but the formula still uses age as a direct predictor and the table reflects that.[4]
Should I use this table if my weight or height differs from the held constants?
Use the table matching your sex for a directional read, then account for the difference. The Mifflin-St Jeor equation scales body weight by 10 and height by 6.25, so a 10 kg weight difference shifts TDEE by roughly 150–190 kcal/day depending on activity level.[1] For an exact figure based on your measurements, use the TDEE Calculator directly.
References
- 1 A new predictive equation for resting energy expenditure in healthy individuals (Mifflin-St Jeor 1990) — American Journal of Clinical Nutrition (1990)
- 2 Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults (Frankenfield 2005 ADA review, recommends Mifflin-St Jeor for general populations) — Journal of the American Dietetic Association (2005)
- 3 Human Energy Requirements: Report of a Joint FAO/WHO/UNU Expert Consultation — activity multipliers and physical activity levels — FAO / WHO / UNU Technical Report (2004) (2004)
- 4 Daily energy expenditure through the human life course (Pontzer et al., doubly labelled water analysis, n = 6,421) — Science (2021)
- 5 Variability in human energy expenditure and the implications for diet assessment (Livingstone and Black) — Nutrition Research Reviews (2003)