Calorie Calculator

Find your daily calorie target for losing, maintaining or gaining weight.

Please note: For general information only. This is not medical advice — speak to a doctor or registered dietitian before changing your diet, training or medication.

What the Calorie Calculator does

Your calorie target starts from TDEE and adjusts for your goal. A deficit of about 7,700 calories corresponds to a kilogram of body mass, so a 550 calorie daily deficit produces roughly half a kilo a week.

Formula

TDEE = BMR × Activity factor
Deficit per day = (Target kg per week × 7,700) ÷ 7
Target = TDEE − deficit (or + surplus)

Inputs explained

Input	Unit	Required	Notes
Units	one of 2 options	Yes	—
Weight	kg or lb	Yes	Accepts 1 or more.
Height	cm or ft + in	Yes	Accepts 1 or more.
Age	years	Yes	Accepts 1 or more, up to 120.
Sex	one of 2 options	Yes	—
Activity level	one of 5 options	Yes	—
Goal	one of 3 options	Yes	—
Target rate	kg per week	In some modes	Accepts 0 or more, up to 1.5. Shown in 4 of the 6 modes.

How to use it

Choose Units and Sex.
Enter Weight, Height and Age.
Fill in the remaining inputs the form shows for your choice.
Select Calculate.

Worked example

A 35-year-old man, 90 kg, 178 cm, lightly active, aiming to lose 0.5 kg a week.

Weight: 90 kg
Height: 178 cm
Age: 35
Activity: Light
Goal: Lose
Rate: 0.5

TDEE about 2,585, minus a 550 daily deficit = 2,035 calories a day.

Frequently asked questions

Is a 1,200 calorie diet safe?

It is the commonly cited floor for women and is already very low. Below that, meeting micronutrient needs is difficult and muscle loss accelerates. Get medical supervision first.

Do I need to count calories forever?

No. Most people track for a few months to learn portion sizes and food energy density, then maintain by habit with occasional check-ins.

Method and sources

Method. Maintenance calories from a predictive resting-metabolic-rate equation scaled by an activity factor, then adjusted by the deficit or surplus chosen for the goal.

Assumptions

Maintenance is stable over the period. It is not: expenditure falls as weight falls, so a figure calculated today overstates the deficit later.
Intake is measured accurately, which under free-living conditions is where most of the error in practice comes from.

Limitations

The activity multipliers are convention, not measurement, and no authority defines them.
A calorie target is not a nutrition plan. It says nothing about protein adequacy, micronutrients, or whether the deficit is safe for the person entering it.
Not appropriate for children, pregnancy, or anyone managing an eating disorder or a condition affecting metabolism.

Sources

A new predictive equation for resting energy expenditure in healthy individuals — The American Journal of Clinical Nutrition (Mifflin, St Jeor et al.), 1990. The resting metabolic rate underlying the maintenance figure.