Free tool
Calorie & TDEE calculator
Find how many calories you should eat a day to lose, maintain or gain — using the science-backed Mifflin-St Jeor formula. Then let LensNutra track it automatically.
Want this tracked for you automatically?
How the calorie calculator works
This tool uses the Mifflin-St Jeor equation — the formula clinicians consider the most accurate for estimating Basal Metabolic Rate (BMR), the calories your body burns at complete rest. Your BMR is then multiplied by an activity factor (1.2 for sedentary up to 1.9 for very active) to get your TDEE (Total Daily Energy Expenditure) — the calories you burn on a typical day, also known as your maintenance level.
Calories to lose or gain weight
To lose weight, eat below your TDEE. A deficit of about 500 calories a day equals roughly one pound of fat per week. To gain, eat a moderate surplus. We floor weight-loss targets at a sensible minimum so the number stays safe. For a deeper dive, read how many calories to lose weight and how to track macros.
From a number to a habit
Knowing your target is step one — hitting it every day is the hard part. That’s what LensNutra is for: snap a photo of your meal and it logs the calories and macros against this exact goal, so you always know how much you have left.
4.9 · Loved by 500,000+ people
Claim your 3-day free trial
Start scanning your meals in seconds. No ads, cancel anytime.