How to Calculate Your Maintenance Calories (Step-by-Step Guide)

Your maintenance calories represent the number of calories your body needs each day to maintain its current weight. Understanding this number is the single most important step in any nutrition plan, whether your goal is fat loss, muscle gain, or simply staying healthy. Without knowing your baseline, every diet strategy is guesswork.

What Are Maintenance Calories?

Maintenance calories are the total daily energy expenditure (TDEE) required to keep your weight stable. This includes the energy your body uses at rest (your basal metabolic rate), the energy spent digesting food (the thermic effect), and the energy burned through physical activity and daily movement. When calories consumed equal calories burned, your weight stays the same.

The Mifflin-St Jeor Formula

The gold standard for estimating basal metabolic rate (BMR) in the general population is the Mifflin-St Jeor equation. Published in 1990 and validated across multiple studies, it tends to be more accurate than older equations like Harris-Benedict.

If you know your body fat percentage, the Katch-McArdle formula can be even more precise because it accounts for lean body mass directly. Our calculator uses Mifflin-St Jeor by default and automatically switches to Katch-McArdle when you provide body fat data.

Activity Multipliers

Your BMR tells you what you burn at rest. To estimate total daily expenditure, multiply by an activity factor:

• Sedentary (little or no exercise): BMR × 1.2
• Lightly active (1-3 days/week): BMR × 1.375
• Moderately active (3-5 days/week): BMR × 1.55
• Very active (6-7 days/week): BMR × 1.725
• Extra active (physical job + training): BMR × 1.9

Step-by-Step: Use the FitFixLife Calculator

Instead of doing the math by hand, our free calorie calculator handles all of this for you in seconds. Enter your age, sex, height, weight, and activity level, and the tool returns a calorie range — not just a single number. Ranges account for the margin of error inherent in any estimation formula and give you a practical window to work within.

Common Mistakes to Avoid

• Overestimating activity level — Most people with desk jobs are sedentary to lightly active, even if they exercise 3 times a week. Be honest with yourself.
• Treating estimates as exact — Formulas are starting points. Real-world data from tracking your weight over 2-4 weeks is far more accurate.
• Ignoring metabolic adaptation — Your TDEE shifts as your weight, age, and activity change. Recalculate every 4-6 weeks.
• Not accounting for NEAT — Non-exercise activity thermogenesis (walking, fidgeting, standing) can vary by hundreds of calories daily between individuals.

How to Adjust Over Time

Start with your calculated maintenance range and eat within it for two weeks while tracking your weight daily (first thing in the morning). Average the weekly weights. If your weight is stable, you have found your true maintenance. If you are gaining, reduce by 100-200 calories. If you are losing, increase by the same amount. Small adjustments over time beat drastic changes every time.

Disclaimer: This content is for informational purposes only and is not medical advice. Consult a healthcare professional before making changes to your diet.