FotoBiteCalorie and macro calculator
Find out how many calories you need a day and how they split into protein, fat and carbs. It is the same calculation the FotoBite app uses.
What you enter is not stored or shared: the target is worked out right in your browser, or on our server without saving anything if JavaScript is off.
Your daily target
kcal a day
A guide, ±10 %.
- Protein g
- Fat g
- Carbs g
Now you know your target — it helps to see it every day. Snap your food and FotoBite counts the calories and macros and shows what is left of your target.
Count calories from photos in TelegramThe app asks for the same details and uses the same formula: nothing from this page is passed to Telegram.
How it was calculated
- Basal metabolic rate, Mifflin-St Jeor formula: ≈ kcal.
- Activity “”, factor : ≈ kcal a day — kcal more than a sedentary day.
- Goal “”: kcal.
- Total: kcal a day.
- That deficit would take the target below your basal metabolic rate, so it is raised to it: kcal a day. A gentler deficit, but a safe one.
- Protein: g per kg of adjusted body weight — g. Above a healthy weight only part of the extra weight counts.
- Protein: g per kg of lean (fat-free) mass — g.
- Fat — 30 % of calories: g. Carbs — the remaining calories: g.
We can't give you a number
Your basal metabolic rate is ≈ kcal, ≈ kcal with activity. With this goal the target would fall below the safe minimum of kcal a day, so we don't show one.
This goal is below the safe calorie minimum. Double-check height, weight and age — or choose "Maintain".
This calculator is for adults
FotoBite and this calculation are made for people aged 18 and over. Teenagers need extra energy and protein to grow, so their target is best discussed with a doctor.
How your calorie target is calculated
The calculator works in three steps — the same ones the FotoBite app uses.
1. Basal metabolic rate
The energy your body uses at rest. The Mifflin-St Jeor formula:
- men: 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5;
- women: 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161.
2. Activity
The basal rate is multiplied by an activity factor, which gives your daily energy use.
| Activity | Factor |
|---|---|
| Sedentarydesk job, under 5,000 steps, no workouts | 1.2 |
| Light activity1–2 workouts a week or 6–8k steps a day | 1.375 |
| Moderate activity3–5 workouts a week or 8–12k steps a day | 1.55 |
| Active6–7 workouts a week or an on-your-feet job | 1.725 |
| Very activedaily sport plus physical work | 1.9 |
3. Goal
To lose weight, 500 kcal is taken off (−500); to gain muscle, 300 kcal is added (+300); to maintain, the target equals your daily energy use.
The safe minimum
The target never goes below your basal metabolic rate: if a deficit would take it lower, it is raised to that rate. If even that is under 1200 kcal a day for women or 1500 kcal for men, the calculator gives no number — just like the app.
How the macros are calculated
Protein — 1.8 / 1.6 / 2 g per kg for losing weight, maintaining and gaining muscle. It uses an adjusted weight, not your full weight: the Devine ideal weight plus a quarter of anything above it, because fat tissue needs almost no protein. If you know your body fat %, protein is based on lean mass instead: 2.07 / 1.84 / 2.3 g per kg.
Fat — 30 % of calories (9 kcal per gram). Carbs — whatever is left after protein and fat (4 kcal per gram).
Example: a woman, 34, 165 cm, 72 kg, light activity, goal: lose weight. Basal metabolic rate: 10 × 72 + 6.25 × 165 − 5 × 34 − 161 ≈ 1420 kcal. With activity: 1420 × 1.375 ≈ 1953 kcal. Minus 500 kcal for the goal: ≈1453 kcal a day. Protein 109 g, fat 48 g, carbs 145 g.
Frequently asked questions
How many calories should I eat a day?
It depends on your sex, age, height, weight and activity, so there is no single number for everyone. The calculator works out your basal metabolic rate, multiplies it by an activity factor and adjusts it for your goal. The result is a guide: energy use varies between people, so check it against how your weight changes over a few weeks.
How do I calculate my macros?
Start with calories, then protein: 1.6–2 g per kg of adjusted body weight depending on your goal. Fat is 30 % of calories and carbs are the rest. The calculator does this for you and shows the grams.
Which formula does the calculator use?
The Mifflin-St Jeor formula with activity factors from 1.2 to 1.9. The FotoBite app uses the same formula, so with the same details you get the same target here and in the app.
Why won't the calculator go below my basal metabolic rate?
A target below your basal rate is too harsh a deficit, so it is raised to that rate. If the result is still under 1200 kcal a day for women or 1500 kcal for men, the calculator gives no number. Not for pregnant or breastfeeding women. If you have an eating disorder or a chronic condition, talk to your doctor first.
Is my data saved?
No. The target is worked out in your browser and the numbers you enter are not sent anywhere. With JavaScript off the server does the maths: it stores nothing, and your details never appear in the page address.
Can I use the calculator if I'm under 18?
No: the calculator and the FotoBite app are made for adults. Teenagers need energy to grow, so their target is best discussed with a doctor.
This is a guide, not medical advice. Talk to a doctor before changing your diet. The calculator and FotoBite are for adults, 18+.
Not for pregnant or breastfeeding women. If you have an eating disorder or a chronic condition, talk to your doctor first.