Calorie Needs Calculator
An honest estimate of what you burn, and a gentle target if you want to lose weight.
Common questions
How many calories a day does an adult need?
Most adult women need roughly 1,800 to 2,200 calories a day and most adult men need roughly 2,200 to 2,800, depending on size and activity. A small, mostly sedentary older adult may need less, and a tall, active person may need more. This calculator gives you a personal estimate rather than a one-size number.
Why do crash diets fail?
When you cut calories very hard, your body fights back: it slows its energy use, a change called metabolic adaptation, and it burns muscle along with fat. Hunger hormones also rise, so most people regain the weight, sometimes plus extra, once the diet ends. Slow, steady changes keep more muscle and are far easier to hold onto.
How big a calorie deficit should I use to lose weight?
A deficit of about 400 to 500 calories a day below your maintenance number leads to roughly one pound of loss per week for most people. That pace is slow enough to protect muscle and gentle enough to live with. If you take medications or have health conditions such as diabetes, plan any weight loss with your own doctor.
Does metabolism really slow down with age?
Less than most people believe. Recent large studies found that calorie burn per unit of body tissue is quite stable from about age 20 to 60, with a clear decline only after 60. What changes for most people in midlife is less muscle and less daily movement, both of which you can act on with strength exercise and walking.