Assigned sex is one of five details the calorie calculator asks for, alongside your age, height, weight and activity level. Together they produce an estimate of how many calories your body uses in a day.
What the field means
Assigned sex is the classification recorded at birth, male or female, based on physical characteristics such as anatomy or chromosomes. It is usually the entry on your birth certificate.
It is not the same thing as gender identity, which is how you identify. The calculator asks for assigned sex because that is what the equation behind the estimate was built around.
Why it changes the number
The equation uses assigned sex as a stand-in for a few averages that differ between the two groups:
- Basal metabolic rate. The calories your body uses at rest, before you move at all. This is often shortened to BMR.
- The balance of tissue. The average proportions of muscle and other tissue differ, and that changes how much energy movement costs.
- Hormone levels. These sit behind both of the points above.
In practice, your age, assigned sex, height and weight are used together to estimate the calories your body uses at rest. That figure is then scaled by your activity level to give the daily number you see.
What the number is, and what it is not
The result is an estimate, not a measurement. It is a starting point to track against and adjust from, rather than a figure to hit exactly.
Assigned sex is used to pick between two sets of averages, and that is the whole of its job here. The calculator makes no other use of it.
If neither option describes you
Assigned sex does not always match gender identity, and the calculator offers only the two options the equation is built on.
If you are on hormone replacement therapy, or have been, your energy needs may sit closer to the averages for your affirmed gender. Choosing the option that matches your current physiology will give you the closer estimate.
You can also run the calculator both ways and read the two figures as a range. For advice about your own situation, a healthcare professional is the right place to ask.
What else changes the estimate
Age, height, weight and activity level each move the number too, and activity level usually moves it most. Each one has its own article in the Academy if you want to know what it is doing.
If you have feedback on this field or on how the calculator handles it, you can contact our support team by email.