Calorie needs at age 21, male
Daily calorie needs depend on age, sex, size and how much you move. Here is the sum for a 21-year-old man who is 5 ft 10 in and 178 lb.
How it works
Start with resting calories from Mifflin-St Jeor. Take 10 times weight in kilograms and add 6.25 times height in centimeters. Subtract 5 times age. Then add 5 for males or subtract 161 for females. Multiply by an activity factor to get daily calories. At 178 lb the weight term for this 21-year-old man is 807.4, at the lightly active level.
Worked example
Say a man aged 21 is 5 ft 10 in tall and weighs 178 lb. That is 177.8 cm and 80.74 kg. The weight term is 10 × 80.74 = 807.4. The height term is 6.25 × 177.8 = 1111.25. The age term is 5 × 21 = 105. Add 5. The result is 1818.65 at rest. Times 1.375 for the lightly active level is 2500.6, which rounds to 2501 calories a day.
Maintenance calories at every activity level for the same man aged 21 at 5 ft 10 in and 178 lb, with the lightly active level set in the form above.
- Sedentary (little or no exercise)
- 2182 calories a day
- Lightly active (light exercise 1 to 3 days a week)
- 2501 calories a day
- Moderately active (moderate exercise 3 to 5 days a week)
- 2819 calories a day
- Very active (hard exercise 6 to 7 days a week)
- 3137 calories a day
- Extra active (very hard exercise and a physical job)
- 3455 calories a day
Common questions
How big a surplus helps build muscle?
A modest surplus of about 250 calories a day is a common starting point. Larger surpluses tend to add more fat without adding muscle faster. A 250 calorie surplus here means 2751 calories a day for this 21-year-old man at the lightly active level.
Why does age 21 change the result?
The formula takes 5 calories off for every year of age, which reflects that resting burn tends to fall over time. At 21 that is 105 calories. Without the age term this 21-year-old man would burn 1924 calories at rest, or 2645 a day at the lightly active level.
How accurate is a calorie estimate?
It is a starting estimate. Track your weight over two or three weeks and adjust the target up or down based on what actually happens. For this 21-year-old man, a 5 percent error on 2501 calories is 125 calories a day.
What is the difference between BMR and TDEE?
BMR is what your body burns at rest. TDEE adds the calories you use moving and exercising. It is always higher. For this man aged 21 at 178 lb, BMR is 1819 calories and TDEE at the lightly active level is 2501.
Which activity level should I pick?
Pick the one that matches a typical week, not your best week. If you sit most of the day and train a few times, lightly or moderately active is usually closer than very active. Across the five levels this 21-year-old man ranges from 2182 to 3455 calories a day, and the lightly active level gives 2501.