Calories in Kilojoules: ${(calories * 4.1868).toFixed(2)} kJ

Guidelines:

• To maintain weight, consume ${calories.toFixed(2)} calories/day.
• To lose weight, aim for ${(calories - 500).toFixed(2)} calories/day.
• To gain weight, aim for ${(calories + 500).toFixed(2)} calories/day.

This Calorie Calculator relies on multiple equations to provide an estimated average result. One of the earliest methods, the Harris-Benedict Equation, was originally developed to calculate basal metabolic rate (BMR)—the energy expended at rest per day. It was revised in 1984 for improved accuracy and remained widely used until 1990, when the Mifflin-St Jeor Equation was introduced. The Mifflin-St Jeor Equation also determines BMR and has been found to be more precise than the revised Harris-Benedict Equation.

In contrast, the Katch-McArdle Formula calculates resting daily energy expenditure (RDEE), factoring in lean body mass—something neither the Mifflin-St Jeor nor Harris-Benedict Equations do. Among these, the Mifflin-St Jeor Equation is generally regarded as the most accurate for BMR calculations, except for lean individuals who know their body fat percentage, where the Katch-McArdle Formula may be more precise. The calculator incorporates the following three equations: