Simple daily calorie intake

Five activity options are supported: sedentary, light, moderate, active, and very_active. Any other activity label is rejected as invalid_input instead of being silently mapped to a nearby factor. Use it on this page at no charge, or call the API at $0.002 per successful request when you need reproducible intake numbers in apps, logs, or tests.

How daily calorie intake is estimated from body stats and activity

Second, the engine multiplies basal metabolic rate by a physical-activity factor drawn from the classic five-level Harris-Benedict scale: sedentary at one point two for desk work with little exercise, light at one point three seven five for training one to three days a week, moderate at one point five five for three to five sessions, active at one point seven two five for hard training most days, and very_active at one point nine for very hard training or a physical job. The product is rounded to the nearest whole kilocalorie and returned as calories_per_day, which is the primary result you should display. The response also echoes the normalized inputs, the basal rate to two decimal places, the activity factor that was applied, a method tag mifflin_st_jeor, a formula string you can print next to the answer, and the unit kcal/day so a client can show the working without re-deriving coefficients.

Input contract, supported activity levels, and error behaviour

Missing or non-finite weight, height, or age, a sex value outside the accepted set, and values above the documented ceilings also fail, and those failures are not billed. POST a JSON body with five required fields. weight is body mass in kilograms, a finite positive number up to five hundred, with aliases weight_kg, kg, and mass. height is standing height in centimeters, from thirty to three hundred, with aliases height_cm and cm. age is years of life from zero to one hundred twenty, with aliases age_years and years. sex selects the Mifflin-St Jeor constant and accepts male, m, or man, and female, f, or woman, case-insensitive, with alias gender. activity is the closed list sedentary, light, moderate, active, and very_active, with aliases activity_level and pal; hyphens and spaces are folded to underscores so Very Active and very-active both become very_active. Any other activity token, including empty strings, extra, athlete, extreme, or a free-text job title, fails with invalid_input and a message that names the supported options. That rejection is the contract, not a hint: the calculator will not guess a factor for an unknown lifestyle label, because a guessed multiplier would silently shift calories_per_day by hundreds of kilocalories. On success the body includes calories_per_day as an integer, bmr, activity_factor, the canonical activity and sex strings, the numeric inputs, method, formula, and unit. Example: eighty kilograms, one hundred eighty centimeters, thirty years, male, sedentary yields basal metabolic rate one thousand seven hundred eighty and calories_per_day two thousand one hundred thirty-six, because one thousand seven hundred eighty times one point two is two thousand one hundred thirty-six exactly. Pair the free browser run on this page with the priced API when you need the identical mathematical result inside an automated pipeline.

Where a simple calorie intake calculator is used

Extreme or unknown activity strings are rejected so a typo cannot inflate a meal plan; the five-option select on the web form is the same closed set the API validates. On this page the work runs entirely in your browser; through the API each successful lookup costs $0.002, failed validation is not charged, and nothing is stored after the response returns. That split—free interactive exploration and a priced, identical API—matches the rest of the KIT tier-A catalog and lets you move from a classroom demo to an automated pipeline without changing the mathematical result.