Use this energy estimate as a starting point for planning or comparing intake and activity assumptions when body measurements and activity level are entered consistently.

Basal metabolic rate (kcal/day)

Basal metabolic rate in kilocalories per day.

Activity level

Weekly activity pattern.

Scale a basal metabolic rate into daily maintenance calories by activity level. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Maintenance calories (kcal/day)

Estimated maintenance calories per day.

• BMR and daily-expenditure equations estimate population averages rather than an individual's metabolism. Body composition, age, sex, health, medication, pregnancy, climate, activity measurement, and adaptive changes can shift actual needs.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Track weight, intake, performance, and wellbeing over several weeks and adjust gradually. Seek clinical or dietetic guidance for medical conditions, pregnancy, eating disorders, or major weight changes.

• Basal Metabolic Rate

  Estimate daily resting energy expenditure with the Mifflin-St Jeor equation.

• Ammonia Excretion

  Estimate daily total-ammonia-nitrogen excretion from biomass and an externally determined excretion rate.

• Kleiber BMR

  Estimate basal metabolic rate across animals with Kleiber's law: BMR = 70 x bodyMass^0.75 kilocalories per day.