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FITTA tool

Find out how many calories you burn in a day

Estimate daily calorie burn with Mifflin-St Jeor and a 1.2–1.9 activity factor

These calculators provide estimates based on population-level formulas and do not replace assessment by a dietitian, physician or exercise professional.

Your data

Biological sex
Metabolic formulas use different constants by biological sex.
3–5 sessions per week

Turn TDEE into today's targets in FITTA

FITTA calculates calorie, training, and hydration targets from your expenditure and updates Home as you log food and workouts.

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Practical guide

How to use FITTA better.

TDEE, total daily energy expenditure, is an estimate of the calories your body uses in 24 hours: resting metabolism, digestion, spontaneous movement, and training. This calculator runs the Mifflin-St Jeor equation (1990) and multiplies the result by an activity factor from 1.2 to 1.9. It is a starting point for maintenance, a cut, or a surplus, not a lab test. Treat the number as a population estimate for your sex, size, age, and routine. A registered dietitian or physician should override it when a medical condition is in play.

What total daily energy expenditure actually is

Total daily energy expenditure has four pieces. Basal metabolic rate (BMR) is the energy organs, temperature, and vital functions use at rest. The thermic effect of food, about 8 to 12 percent of intake, covers digestion. NEAT covers steps, posture, and daily chores. EAT is structured training.

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In a desk job, BMR often accounts for 60 to 75 percent of TDEE. NEAT varies more: two adults at 176 lb (80 kg) can differ by 300 to 600 kcal outside the gym. The activity factor is a population multiplier, not a wearable. TDEE is not workout calories; it is the 24-hour budget. Eating at TDEE tends to hold weight; below is a deficit; above is a surplus. This tool estimates a midpoint from sex, weight, height, age, and routine. It does not diagnose a slow metabolism.

How this TDEE calculator runs the numbers

The Mifflin-St Jeor equation (Mifflin, St Jeor et al., 1990) estimates BMR in kcal per day from weight in kilograms, height in centimeters, and age in years. Men: BMR = 10 × weight + 6.25 × height − 5 × age + 5. Women: BMR = 10 × weight + 6.25 × height − 5 × age − 161. Convert imperial first: pounds ÷ 2.205, inches × 2.54. TDEE here is that BMR times the classic PAL factor, 1.2 to 1.9.

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Male example, 80 kg (176 lb), 175 cm (5 ft 9 in), age 30: BMR = 10 × 80 + 6.25 × 175 − 5 × 30 + 5 = 800 + 1,093.75 − 150 + 5 = 1,748.75 kcal. Times 1.55, TDEE is about 2,711 kcal. Female example, 65 kg (143 lb), 165 cm (5 ft 5 in), age 28: BMR = 10 × 65 + 6.25 × 165 − 5 × 28 − 161 = 650 + 1,031.25 − 140 − 161 = 1,380.25 kcal. Times 1.375, about 1,898 kcal. Mifflin-St Jeor usually beats original Harris-Benedict on mean error in healthy adults, but it still ignores lean mass.

  • 1.2 sedentary: desk job, no training
  • 1.375 light: 1 to 3 sessions per week
  • 1.55 moderate: 3 to 5 sessions per week
  • 1.725 very active: 6 to 7 sessions per week
  • 1.9 athlete: two-a-days or a heavy physical job

How to read the result and correct it

The headline number is estimated maintenance, not a fat-loss or hypertrophy target. A 300 to 500 kcal daily deficit often yields 0.3 to 0.5 kg (0.7 to 1.1 lb) per week if TDEE is close, because 1 kg of adipose tissue is about 7,700 kcal (roughly 3,500 kcal per pound). A surplus of the same size favors gain, with more or less fat depending on training and protein.

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Read TDEE next to BMR. Maintenance under 1,600 kcal for a 70 kg (154 lb) adult at factor 1.55 means bad inputs. A value over 3,800 kcal without a heavy job is usually an inflated 1.9. Run the number for 14 to 21 days and watch a moving average of scale weight. A drop faster than 0.7 kg (1.5 lb) per week with no planned deficit, or a rise at maintenance, calls for a 150 to 250 kcal nudge. That loop beats swapping formulas.

Common TDEE mistakes

The usual miss is overstating activity. Four lifting sessions, nine desk hours, and seven hours of sleep is 1.375 or 1.55 for most people, not 1.725. The second miss is double-counting: a high factor plus watch calories. The 1.55 multiplier already assumes three to five weekly sessions. Wrist estimates inflate EAT; use them for trend, not for an extra 400 kcal at dinner.

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The third is treating Mifflin-St Jeor as biology. It was derived in adults, with mean error around 10 percent. Hypothyroidism, medications, crash-diet recovery, pregnancy, and pediatrics sit outside this page. Update weight after a 3 to 4 kg (7 to 9 lb) change: BMR falls as mass falls, and an old TDEE becomes a silent, growing deficit.

  • Overstating the weekly activity factor
  • Adding watch calories on top of the factor
  • Eating at BMR and calling it TDEE
  • Skipping a recalc after 7 to 9 lb
  • Treating the equation as a clinical diagnosis

Using TDEE in training and diet

Pick the goal after TDEE. For fat loss, cut 15 to 20 percent and keep a floor near 60 percent of TDEE. For muscle gain, 10 to 15 percent above is usually enough; a 500 kcal surplus in an intermediate lifter often adds fat faster than tissue. Maintenance is eating at TDEE while you periodize load.

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Anchor protein at 1.6 to 2.2 g/kg (0.7 to 1.0 g/lb) for recomposition, fat at 20 to 35 percent of calories, and let carbohydrate fill the rest on training days. TDEE only sets the calorie envelope. In FITTA, expenditure becomes the day's targets: meals, water, training, and Home update together. The plan FITTA calculates from your log keeps January's number from becoming July's diet.

TDEE, BMR, and watch calories: do not double-count

BMR and TDEE are not interchangeable. Eating at BMR is an aggressive deficit: even 1.2 already sits 20 percent above basal. Do not treat a hard training day's TDEE as the weekly mean either. Five training days and two rest days already live inside 1.55. Recalculating Saturday at 1.2 and Monday at 1.725 builds a sawtooth your appetite will not follow.

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Pair this page with the BMR calculator to compare Mifflin-St Jeor and Harris-Benedict, and with the calorie-target calculator to project weeks to a weight goal. TDEE is the axis. Without it, macros and protein have no envelope.

Frequently asked questions

What is TDEE and how do I calculate it

TDEE is your estimated 24-hour calorie burn. Get BMR with Mifflin-St Jeor: 10 times weight in kg, plus 6.25 times height in cm, minus 5 times age, plus 5 for men or minus 161 for women. Multiply by 1.2 if you are sedentary up to 1.9 if you are an athlete. That product is maintenance, not a finished meal plan.

TDEE vs BMR what is the difference

BMR is resting energy. TDEE is BMR times an activity factor, so it already folds in digestion, daily movement, and the training load that belongs to that band. Eating at BMR is a steep deficit for almost everyone. Use BMR as the physiological floor and TDEE to set maintenance, a cut, or a surplus across the week.

How many calories should I eat to lose weight with my TDEE

Subtract 15 to 20 percent of TDEE, or about 300 to 500 kcal, and watch scale trend for two to three weeks. One kilogram of fat is about 7,700 kcal (about 3,500 kcal per pound), so a 500 kcal daily deficit points to roughly 0.45 kg (1 lb) per week if TDEE is right. If the scale does not move, the activity factor is probably too high.

How do I choose a TDEE activity factor

Judge the whole week, not the workout day. A desk job with no training is 1.2. One to three sessions is 1.375. Three to five is 1.55. Six to seven is 1.725. Two-a-days or a heavy job is 1.9. When unsure, pick the factor just below. Overstating PAL is the usual way to invent a deficit that never shows up on the plate.

Is the Mifflin-St Jeor TDEE formula accurate

It is the equation with the lowest average error in healthy adults versus classic Harris-Benedict, typically around 10 percent. It does not measure lean mass or hormones. Very lean athletes and people with obesity can deviate more. Treat the output as a starting point and correct it with weight trend. It does not replace a clinician.

How do I use TDEE to build muscle

Add 10 to 15 percent to TDEE and train with progressive overload. A surplus larger than 500 kcal speeds up fat gain once you are past the novice stage. Keep protein around 1.6 to 2.2 g per kg (0.7 to 1.0 g per lb) and use carbohydrate to fuel training volume. Recalculate TDEE every 3 to 4 kg (7 to 9 lb) gained, because maintenance rises with body weight.

Does TDEE change over time

Yes. Weight, age, NEAT, and the deficit itself change expenditure. In a calorie cut the body often reduces spontaneous movement, and BMR dips a little as mass drops. Recalculate when body weight moves a few kilograms or when training jumps to a new activity band. A January TDEE rarely still fits in July without an update.

Keep exploring

BMR Calculator

Compare Mifflin-St Jeor and revised Harris-Benedict for resting burn

Daily calorie calculator

Daily target for fat loss, maintenance or muscle gain, plus time to goal weight

Macro calculator

Daily protein, carbs, and fat in grams from your goal

These calculators provide estimates based on population-level formulas and do not replace assessment by a dietitian, physician or exercise professional.