FITTA
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FITTA tool

How many calories to eat each day for your goal

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

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
Goal
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Turn this calorie target into a daily FITTA plan

FITTA logs meals, workouts and scale weight, then recalculates the plan when your pace drifts off the projection.

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Practical guide

How to use FITTA better.

This calculator sets a daily calorie target from your energy expenditure and goal: lose fat, hold weight, or gain mass. It uses the 1990 Mifflin-St Jeor equation, multiplies by an activity factor, then applies a deficit or surplus of 7,700 kcal per kilogram (about 3,500 kcal per pound). Enter biological sex, age, weight, height, activity level, weekly pace, and target weight. The output is a population estimate, not a clinical plan. Start there and adjust from the scale over the following weeks.

How the daily calorie target is calculated

The daily target starts with basal metabolic rate, estimated by the 1990 Mifflin-St Jeor equation. Men: 10 × weight in kg + 6.25 × height in cm − 5 × age in years + 5. Women: the same base, with −161 instead of +5. A man at 80 kg (176 lb), 175 cm (5 ft 9 in) and 30 years old lands at 10 × 80 + 6.25 × 175 − 5 × 30 + 5 = 1,748.75 kcal. A woman at 70 kg (154 lb), 165 cm (5 ft 5 in) and 28 years old lands at 10 × 70 + 6.25 × 165 − 5 × 28 − 161 = 1,430.25 kcal.

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TDEE is BMR times the activity factor. In the male example at 1.55, TDEE is 1,748.75 × 1.55 = 2,710.6 kcal. The goal applies 7,700 kcal per kilogram of adipose tissue (about 3,500 kcal per pound): daily adjustment = (kg per week × 7,700) ÷ 7. Losing 0.25 / 0.5 / 0.75 / 1 kg per week (0.55 to 2.2 lb) needs a 275 / 550 / 825 / 1,100 kcal deficit; gaining uses the same values as a surplus. Maintenance uses TDEE. The calculator will not recommend eating below 60% of TDEE: if the pace would break that floor, the target is capped and the timeline stretches.

  • Sedentary: BMR × 1.2 (desk job, no training)
  • Lightly active: BMR × 1.375 (1 to 3 sessions per week)
  • Moderately active: BMR × 1.55 (3 to 5 sessions)
  • Very active: BMR × 1.725 (6 to 7 sessions)
  • Athlete: BMR × 1.9 (two-a-days or a heavy physical job)

Deficit, maintenance, and surplus in real numbers

Fat loss needs a weekly-average deficit. On a 2,711 kcal TDEE, the default 0.5 kg (1.1 lb) per week pace lands at 2,711 − 550 = 2,161 kcal. A 0.25 kg pace sits at 2,436 kcal and usually protects more lean mass. Paces of 0.75 kg and 1 kg (1,886 and 1,611 kcal here) fit people with more fat to lose and a TDEE high enough to stay above the floor.

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Maintenance is TDEE. Use it at goal weight or for two to four stable weeks between blocks. A muscle-gain surplus is smaller than a typical fat-loss deficit: 0.25 kg per week adds about 275 kcal (2,986 kcal in the example). Half a kilogram of gain per week mixes in more fat, especially past the novice stage. A woman with an 1,800 kcal TDEE asking for 1 kg per week would land at 700 kcal; the 60% floor clamps to 1,080 kcal and the true pace is no longer 1 kg per week.

How to read the result and the time projection

The headline number is your daily calorie target. Under it sit TDEE, the daily deficit or surplus, and BMR. The timeline only appears when target weight matches the goal: fat loss needs a lower weight; gaining needs a higher one. Formula: weeks = |target weight − current weight| ÷ kg per week. Five kilograms at 0.5 kg per week is 10 weeks, about 2.3 months (4.345 weeks per month).

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That date assumes a constant pace. In practice expenditure falls as weight drops, NEAT often shrinks in a deficit, and the scale mixes water and glycogen. Swings of 0.5 to 1.5 kg over a few days do not cancel the deficit. Use a 7-day fasted average. If it has not moved in the expected direction after 14 days, shift 150 to 200 kcal. Recalculate the card every 4 to 5 kg.

Common mistakes that warp the target

The most common miss is overstating activity. Four lifting sessions and a desk job sit closer to 1.375 than to 1.725. Inflating the factor erases the deficit without the plate changing. When unsure, pick the lower tier.

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Another miss is treating 7,700 kcal (or 3,500 kcal per pound) as the weekly scale change. That figure describes adipose tissue, not water, glycogen, or gut content. Copying someone else's target, logging only lunch and dinner, or ripping up the plan after every daily wiggle breaks the model. The equation is a population estimate. This page is a starting point, not a substitute for a dietitian or physician when there is a medical condition, disordered eating history, or an aggressive cut.

  • Picking very active or athlete without the matching volume
  • Forcing 1 kg per week on a low TDEE and hitting the 60% floor
  • Reading every daily scale swing as a failed deficit
  • Copying a target from someone with a different body or routine
  • Cutting protein and lifting, then losing lean mass with the fat

Putting the target into training and diet

The target only works if weekly-average intake lands near it. Spread calories across 3 to 5 meals. In a deficit, anchor protein at 1.8 to 2.4 g per kg and fat between 20% and 35% of calories; carbohydrate covers training. In a surplus, extra carbohydrate does more good on lifting days.

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Strength work 3 to 5 times per week is what separates fat loss from weight loss. Thirty minutes of easy running burns on the order of 250 to 350 kcal, less than a weekend off-plan. Do not expect 0.5 kg per week of pure muscle: 0.25 kg is the useful ceiling for intermediates. FITTA calculates the target and plots meals, training, and scale weight on the same chart; if the average drifts, the plan is recalculated from your logs.

  • Hit the weekly average, not every isolated meal
  • Weigh fasted and use a 7-day mean
  • Keep lifting in a deficit to hold lean mass
  • For gaining, prefer 0.25 kg per week to a wide surplus

When to recalculate as body weight changes

Recalculate after 4 to 5 kg of change, after a clear routine shift, or if a two-week average misses the chosen pace by more than 0.2 kg per week. BMR falls with body weight: the same 175 cm, 30-year-old man now at 75 kg instead of 80 kg drops BMR to 10 × 75 + 6.25 × 175 − 5 × 30 + 5 = 1,698.75 kcal and moderate TDEE to 2,633 kcal. Keeping the old target quietly steepens the deficit.

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Do not change the target every morning. Give two weeks of real adherence. Once you hit the goal weight, switch to maintenance for at least two weeks: glycogen and water refill and the scale ticks up without that being regained fat.

Frequently asked questions

How many calories should I eat to lose 0.5 kg per week

This page uses 7,700 kcal per kilogram of adipose tissue, about 3,500 kcal per pound. Half a kilogram per week needs a 3,850 kcal weekly deficit, or 550 kcal per day below TDEE. On a 2,711 kcal TDEE the target is 2,161 kcal. That is an average: a high day has to be offset later. A low TDEE may not support faster paces without hitting the 60% floor.

How many calories are in 1 kg of body fat

The planning convention is 7,700 kcal per kilogram of adipose tissue, matching the classic 3,500 kcal per pound. It is not the same as a one-week scale swing, because water, glycogen, and gut content move too. A 1,100 kcal daily deficit points to about 1 kg of fat in seven days only if average intake and TDEE are actually correct.

How do I calculate calories to gain muscle

Add a surplus of (kg per week × 7,700) ÷ 7 to TDEE. At 0.25 kg per week that is about 275 kcal above maintenance. On a 2,711 kcal TDEE the target is 2,986 kcal. Larger surpluses move the scale faster, but a growing share is fat. Pair the surplus with lifting and 1.6 to 2.2 g of protein per kilogram.

How long will it take to reach my goal weight

Divide the weight gap by the weekly pace. Ten kilograms at 0.5 kg per week is 20 weeks, about 4.6 months (the tool uses 4.345 weeks per month). The date assumes steady adherence. If the target weight sits in the opposite direction from the selected goal, no timeline is shown. Recalculate every 4 to 5 kg because TDEE changes with body weight.

Is it safe to eat under 1,200 calories a day to lose faster

This calculator floors intake at 60% of TDEE, not at a fixed 1,200 kcal. On an 1,800 kcal TDEE the floor is 1,080 kcal; on 2,700 kcal it is 1,620 kcal. Going under that raises lean-mass loss, NEAT drop, and rebound risk. If the requested pace would break the floor, the target is capped. Prefer 0.25 to 0.5 kg per week.

Why am I not losing weight on a calorie deficit

Most of the time the deficit exists only on paper. Activity is set too high, portions are under-logged, or weekends erase the weekday cut. The scale can also hold water after hard training or more sodium. Check a 14-day average. If it has not dropped, cut 150 to 200 kcal or step the activity factor down one tier.

Does a calorie calculator replace a dietitian

No. Mifflin-St Jeor and activity factors are population estimates, often off by a few hundred kcal. They are a starting point and a way to sketch a timeline. Anyone with a medical condition, weight-altering medication, a history of disordered eating, or a plan for an aggressive cut needs professional care. Then tune the number from your actual scale response.

Keep exploring

TDEE Calculator

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

Macro calculator

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

Ideal Weight Calculator

Healthy BMI range plus Devine, Robinson, Miller, and Hamwi estimates

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