Calorie needs at age 20, female
This page estimates total daily energy use. The sample is a woman aged 20 at 5 ft 4 in and 150 lb, and the table shows every activity level.
How it works
Daily calories equal resting calories times an activity factor. Resting calories come from Mifflin-St Jeor: 10 times kilograms plus 6.25 times centimeters minus 5 times age, with 5 added for males or 161 taken off for females. The factor runs from 1.2 to 1.9. This 20-year-old woman uses a factor of 1.375 for the lightly active level.
Worked example
Say a woman aged 20 is 5 ft 4 in tall and weighs 150 lb. That is 162.56 cm and 68.04 kg. The weight term is 10 × 68.04 = 680.4. The height term is 6.25 × 162.56 = 1016. The age term is 5 × 20 = 100. Subtract 161. The result is 1435.4 at rest. Times 1.375 for the lightly active level is 1973.7, which rounds to 1974 calories a day.
Maintenance calories at every activity level for the same woman aged 20 at 5 ft 4 in and 150 lb, with the lightly active level set in the form above.
- Sedentary (little or no exercise)
- 1722 calories a day
- Lightly active (light exercise 1 to 3 days a week)
- 1974 calories a day
- Moderately active (moderate exercise 3 to 5 days a week)
- 2225 calories a day
- Very active (hard exercise 6 to 7 days a week)
- 2476 calories a day
- Extra active (very hard exercise and a physical job)
- 2727 calories a day
Common questions
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 20-year-old woman, a 5 percent error on 1974 calories is 99 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 woman aged 20 at 150 lb, BMR is 1435 calories and TDEE at the lightly active level is 1974.
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 20-year-old woman ranges from 1722 to 2727 calories a day, and the lightly active level gives 1974.
How big a calorie deficit is reasonable for weight loss?
A deficit of 500 calories a day is a common starting point and works out to roughly half a kilogram a week. Smaller deficits are slower and easier to keep up. A 500 calorie deficit here means 1474 calories a day for this 20-year-old woman at the lightly active level.
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 2224 calories a day for this 20-year-old woman at the lightly active level.