Calories by activity level
Activity changes the calorie answer more than most people expect. The table below puts all five levels side by side. Enter your age, size and activity to see how many calories you use each day. The example below is a woman aged 45 who is 5 ft 6 in tall and weighs 165 lb.
How it works
Resting calories are 10 times weight in kilograms plus 6.25 times height in centimeters minus 5 times age. Add 5 for males or subtract 161 for females. Multiply by 1.2 for little exercise up to 1.9 for very hard training. For a woman aged 45 at the moderately active level the fixed adjustment is minus 161.
Worked example
A woman aged 45 is 167.64 cm tall and weighs 74.84 kg. Multiply weight by 10: 10 × 74.84 = 748.4. Multiply height by 6.25: 6.25 × 167.64 = 1047.75. Subtract 5 × 45 = 225. Subtract 161. The total is 1410.15, or 1410 calories at rest. Multiply 1410.15 by 1.55 for the moderately active level. That gives 2185.7, or 2186 calories a day.
Maintenance calories at every activity level for the same woman aged 45 at 5 ft 6 in and 165 lb, with the moderately active level set in the form above.
- Sedentary (little or no exercise)
- 1692 calories a day
- Lightly active (light exercise 1 to 3 days a week)
- 1939 calories a day
- Moderately active (moderate exercise 3 to 5 days a week)
- 2186 calories a day
- Very active (hard exercise 6 to 7 days a week)
- 2433 calories a day
- Extra active (very hard exercise and a physical job)
- 2679 calories a day
Common questions
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 1686 calories a day for this 45-year-old woman at the moderately 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 2436 calories a day for this 45-year-old woman at the moderately active level.
Why does age 45 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 45 that is 225 calories. Without the age term this 45-year-old woman would burn 1635 calories at rest, or 2535 a day at the moderately 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 45-year-old woman, a 5 percent error on 2186 calories is 109 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 45 at 165 lb, BMR is 1410 calories and TDEE at the moderately active level is 2186.