Maintenance Calorie Calculator

What "maintenance calories" actually means

Maintenance calories are the daily intake at which your weight stays the same over time — not the same on any single day, but the same as a 14-day rolling average. It is the sum of four components: basal metabolic rate (60–70% of total), the thermic effect of food (5–10%), exercise activity, and NEAT — non-exercise activity thermogenesis like walking, standing, and fidgeting (15–30%, the most variable component person to person). Calculators estimate the first two and use an activity multiplier for the rest.

Why the activity multiplier is the noisy part

The Mifflin-St Jeor BMR equation has a published prediction error of ±5%. The activity multiplier has ±10–15% error. NEAT — the part that turns BMR into maintenance — is the single largest source of variance between people of the same height, weight, age, and training schedule. James Levine's pioneering 1999 NEAT studies at Mayo Clinic showed that NEAT alone can vary by 2,000 kcal/day between sedentary office workers and active manual labourers of the same height and weight. Two people described by their friends as "the same activity level" can have 400–600 kcal/day of real maintenance difference. This is why a calculator gives you a starting point, not a final answer.

Finding your real maintenance — the 14-day trial

The fastest reliable way to find your actual maintenance number: eat the calculator's prediction for 14 days, track every meal, weigh yourself daily on the same scale at the same time. Compute the average of days 1–7 and the average of days 8–14. If those two averages are within ±0.5 lb (0.2 kg), the calculator is right for you. If you gained, drop daily calories by 100 and run another 14 days. If you lost, add 100 and run another 14 days. Most people land on their true maintenance within 2–3 cycles.

Why your maintenance changes — and when to recalculate

Maintenance is not a constant. It changes with weight (every 10 lbs lost drops it by ~50–100 kcal), training volume (more exercise increases it), and age (BMR drops ~1–2% per decade after age 30). Recalculate every 3–6 months, or after any 5+ lb change, or after a major change in activity (joining a gym, becoming a parent, changing jobs). Adapting calorie targets to actual energy needs is the difference between maintaining weight and slow drift.

Common mistakes that hide your real maintenance

Under-eating on workout days and over-eating on rest days averages out to maintenance — but lets you believe your tracker numbers are wrong. Forgetting weekends (most people under-track calories on Saturday and Sunday by 200–400 kcal). Ignoring liquid calories (a "small" latte is 200 kcal, two glasses of wine is 250). Eyeballing portion sizes — Western adults underestimate restaurant portions by 30–40% on average. Honest tracking for 2 weeks usually reveals the real intake, not the target you thought you were eating.

Related tools

• TDEE Calculator — same calculation, different framing
• BMR Calculator — three formulas compared
• Calorie Deficit Calculator — for fat loss
• Macro Calculator — splitting maintenance into protein, carbs, fat

Frequently asked questions

What's the difference between maintenance calories and TDEE?

They're the same thing. TDEE (Total Daily Energy Expenditure) is the scientific term; maintenance calories is the everyday term. Both refer to the calorie intake that keeps weight stable over time — BMR plus all energy spent on physical activity, NEAT, and the thermic effect of food. Different calculators may give slightly different numbers because they use different BMR formulas (Mifflin-St Jeor, Harris-Benedict, Katch-McArdle) or different activity multipliers, but the underlying concept is identical.

How accurate is the activity multiplier approach?

Moderate. Indirect calorimetry studies (Müller 2016, Speakman 2021) show activity multipliers have ±10–15% error for any individual — meaning a 2,400 kcal predicted maintenance could actually be 2,040–2,760 kcal. The error comes mostly from NEAT (fidgeting, posture, spontaneous movement) which varies 200–500 kcal/day between people. The calculator gives you a starting point; 2–3 weeks of consistent eating + weight tracking gives you the real number.

Why did my maintenance calories drop after weight loss?

Two reasons. First, a smaller body genuinely needs less energy — every kg of body mass costs roughly 20–25 kcal/day to maintain at rest. Lose 10 kg and BMR drops 200–250 kcal/day before any adaptation. Second, adaptive thermogenesis: NEAT and RMR drop by an additional 5–15% below what body mass alone predicts. This is why the Biggest Loser participants (Fothergill 2016, Obesity) had measured maintenance calories 500+ kcal below predicted six years after the show — adaptation lingers.

How do I find my real maintenance calories?

Run a 14-day maintenance experiment. Eat the predicted number consistently (within ±100 kcal each day), weigh yourself daily, and average the first 7 days vs the last 7 days. If the 7-day rolling average is unchanged (±0.5 lb), you found it. If you gained, drop daily intake by 100 kcal and repeat. If you lost, add 100 kcal and repeat. After 2–3 cycles you'll have your real maintenance within ±50 kcal — accuracy no static calculator can match.

Do I need to adjust maintenance on heavy training days vs rest days?

For most recreational lifters, no — the day-to-day variance in NEAT and food digestion costs more than calorie tracking precision can capture. Eat the same amount every day. For athletes doing 2+ hours of training/day, calorie cycling (higher on training days, lower on rest) is reasonable. The simpler approach is to use a weekly average: total weekly calorie target = maintenance × 7. Spread however you like across days.