How many calories should I eat a day?
It depends on you. Estimate your daily energy, then adjust for your aim. For a 30 year old woman of 65 kg and 165 cm, moderately active, that is about 2,100 kcal to keep her weight and 1,550 to lose slowly.
Updated 21 October 2026. Sources named on the page.
- Why there is no single right number
- Two worked examples: keep, lose and gain
- The floors the calculator will not go below
- The average figure on Australian food labels
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Your own number
Enter your details, choose keep, lose or gain slowly, and get a daily target in kcal and kJ.
Worked examples
Targets are rounded to the nearest 50 kcal. Daily energy is resting energy (Mifflin and St Jeor) times the activity factor.
Two people, moderately active (x1.55)
| Person | Daily energy | Keep | Lose slowly (minus 550) | Gain slowly (plus 300) |
|---|---|---|---|---|
| Man, 30 y, 80 kg, 180 cm | 2,759 kcal | 2,750 kcal | 2,200 kcal | 3,050 kcal |
| Woman, 30 y, 65 kg, 165 cm | 2,124 kcal | 2,100 kcal | 1,550 kcal | 2,400 kcal |
Lowest targets the calculator suggests
| Sex | Floor |
|---|---|
| Women | 1,200 kcal (5,021 kJ) |
| Men | 1,500 kcal (6,276 kJ) |
Sources: Mifflin MD, St Jeor ST and others, American Journal of Clinical Nutrition, 1990; Australian food labels use an average adult daily intake of 8,700 kJ (about 2,079 kcal) as a reference; 1 kcal = 4.184 kJ
Figures and sources checked 21 October 2026. General information, not medical advice.
There is no one right number
Needs rise with size and with activity, and fall with age. Two adults of the same weight can need several hundred kcal apart. The 8,700 kJ average on Australian labels is a yardstick for comparing foods, not a target for you.
The steps
First find your daily energy with the TDEE calculation. Then keep it for weight maintenance, subtract about 550 kcal for slow loss (a common rule of thumb for roughly 0.5 kg a week) or add about 300 kcal to gain slowly.
What this does not cover
The figures are for adults aged 19 and over without a medical condition. They are not for pregnancy, breastfeeding or recovery from an eating disorder. If any of those apply, or you are unsure, talk to a doctor or an accredited practising dietitian.
Questions
How many calories should a woman eat a day?
It depends on her age, size and activity. The worked example above comes to about 2,100 kcal to keep weight for one woman, and the calculator will give you your own figure.
How many calories should a man eat a day?
It depends on age, size and activity. The man in the example keeps weight at about 2,750 kcal. Use the calculator for your own.
What is the lowest I should eat?
The calculator never suggests below 1,200 kcal for women or 1,500 kcal for men. Lower amounts should only be used under medical supervision.
Is a deficit of 550 kcal safe?
It is a modest, commonly used size for healthy adults, but it is not right for everyone. Check with a doctor or dietitian if you have any health concern.
Keep going
Log your meals against the number
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