How to Calculate Your Daily Calorie Needs
Your daily calorie needs depend on your Basal Metabolic Rate (BMR) and activity level. This calculator uses the Mifflin-St Jeor equation, the most accurate formula for estimating calorie needs:
- Men: BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age) + 5
- Women: BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age) - 161
Your Total Daily Energy Expenditure (TDEE) is your BMR multiplied by an activity factor. To lose weight, eat 500 calories below your TDEE. To gain weight, eat 500 calories above it.
AI Food Scanner: How It Works
Our AI food scanner uses Google's Gemini AI to analyze food photos and identify individual items with their nutritional content. Simply upload a photo of your meal, and the AI will:
- Identify each food item in your photo
- Provide its top 3 best guesses for what the food is
- Estimate portion size with small, medium, and large options
- Calculate calories, protein, carbs, and fat per serving
This is the same AI technology powering the FastFlow AI mobile app, which also includes barcode scanning, a verified food database, and daily tracking history.
How Many Calories Should I Eat?
The average adult needs between 1,600 and 3,000 calories per day, but this varies widely based on age, gender, height, weight, and activity level. Here are general guidelines:
| Group | Sedentary | Moderately Active | Active |
|---|---|---|---|
| Women (19-30) | 2,000 | 2,000-2,200 | 2,400 |
| Women (31-50) | 1,800 | 2,000 | 2,200 |
| Men (19-30) | 2,400 | 2,600-2,800 | 3,000 |
| Men (31-50) | 2,200 | 2,400-2,600 | 2,800-3,000 |
Calorie Counting and Intermittent Fasting
Combining calorie counting with intermittent fasting is one of the most effective strategies for weight loss. When you eat within a restricted window (like 16:8), you naturally tend to eat fewer calories. Adding calorie tracking ensures you stay within your target even during your eating window.
FastFlow AI integrates fasting tracking with calorie counting, so you can manage both from a single app. Set your fasting protocol, scan your meals, and watch your progress — all for free.
Frequently Asked Questions
How accurate is the AI food scanner?
The AI scanner provides estimates based on visual analysis. For common foods, accuracy is typically within 10-20% of actual values. For more precise tracking, combine it with barcode scanning in the FastFlow AI app.
Do I need to count calories to lose weight?
Not necessarily, but it helps. Understanding how many calories you consume makes it much easier to create the calorie deficit needed for weight loss. Even tracking for a few weeks builds awareness of portion sizes and calorie-dense foods.
What's the minimum safe calorie intake?
Generally, women should not eat fewer than 1,200 calories per day and men should not go below 1,500 calories per day without medical supervision. Very low calorie diets can cause nutrient deficiencies and metabolic slowdown.