Weight loss

Calorie Deficit Calculator

Find the calorie deficit that fits your goal. The calculator below picks a sustainable pace, projects time-to-goal, and flags when your target dips below safe limits.

A calorie deficit is the gap between calories burned and calories eaten, and that gap is what creates fat loss. One pound of body fat stores about 3,500 kcal, so a daily deficit of 500 kcal produces roughly one pound per week of loss. Hold your weekly loss between 0.5 and 1 percent of body weight; anything faster sacrifices muscle and triggers metabolic adaptation.

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Your daily target

· cal/day

Enter your details and click Calculate

  • BMR · cal/day at rest
  • BMI ·  
  • Lean body mass · kg

Pick your goal

Macros at maintenance

30% protein · 40% carbs · 30% fat

Advanced metrics

Numbers are estimates. Eat at your target for 2 to 3 weeks, track weight, and adjust by ±100 cal/day if it does not match your real maintenance. See how accurate is TDEE?

Show advanced metrics 12 metrics · 7 formulas · 2D macro selector · life-stage

All metrics

Calculate above to populate the full metric table.

All 7 BMR formulas (side-by-side)

Mifflin–St Jeor · Harris–Benedict (revised) · Katch–McArdle · Cunningham · Average · Simple multiplier · Custom

TDEE across activity levels

See how much your TDEE changes between sedentary and athlete. Highlighted bar is your current selection.

Macros: 2D selector

Goal × carb-split matrix: Cut / Maintain / Bulk × Low / Moderate / High carb.

Life-stage adjustments

Luteal phase · Pregnancy (T1/T2/T3) · Breastfeeding · Perimenopause · PCOS

Downward-sloping weight loss line over 12 weeks at a 500 kcal per day deficit, ending at goal weight.
A 500 kcal/day deficit produces about 1 lb of weight loss per week (0.5 percent of body weight).

The math behind a calorie deficit

Daily deficit (kcal) × 7 days = weekly deficit
Weekly deficit ÷ 3,500 = pounds of fat lost per week

The 3,500-kcal-per-pound rule (Wishnofsky, 1958) is an approximation. Real-world loss runs 10 to 20 percent slower because of metabolic adaptation, especially past week four. Plan for the model, then recalibrate against the scale every two to three weeks.

Recommended calorie deficits by pace

  • 0.25 lb/week (gradual): 125 kcal/day deficit. Slow but sustainable. Minimal hunger, no measurable muscle loss, no metabolic adaptation. Best for the last 5 to 10 pounds and for body recomposition.
  • 0.5 lb/week (moderate): 250 kcal/day deficit. The sweet spot for most lifters. Easy adherence, full training performance, near-zero lean mass loss with adequate protein.
  • 1 lb/week (standard): 500 kcal/day deficit. The most common target. Some hunger and minor performance dips, but muscle loss stays under 5 percent of total loss when you hit 1.6 to 2.2 g/kg protein and lift heavy.
  • 1.5 lb/week (aggressive): 750 kcal/day deficit. Higher hunger, sleep can suffer, and 15 to 20 percent of loss comes from muscle without high protein plus resistance training. Reserve for short cuts.
  • 2 lb/week (very aggressive): 1,000 kcal/day deficit. Significant muscle loss risk, metabolic adaptation accelerates, and adherence collapses for most people within four weeks. Use only under medical supervision or at higher body fat percentages.

Never eat below your BMR

Your BMR is the safety floor. Sustained intake below BMR triggers metabolic adaptation: your body downregulates thyroid output, drops NEAT (fidgeting and spontaneous movement), and slows the metabolism beyond what the math predicts. Müller et al. (2015) documented adaptive drops of 15 percent below predicted TDEE in subjects who ate below BMR for six weeks.

If your goal weight forces intake below BMR, choose one of two paths. Accept a slower pace and stretch the cut over more weeks, or raise activity through extra walking and training so the deficit widens without lowering food.

The 1 percent weekly weight loss rule

Cap weekly loss at 1 percent of body weight. A 200-pound person can safely lose 2 pounds per week; a 140-pound person should cap at 1.4 pounds per week. Helms et al. (2014) showed that natural physique athletes who exceeded this 1 percent threshold lost strength and lean mass at measurably higher rates. The leaner you are, the more critical this rule becomes.

Protect muscle during a deficit

Three levers preserve muscle while you cut:

  • Protein: 2.0 to 2.4 g/kg body weight per day (Helms et al., 2014). Use the macro calculator to set grams precisely.
  • Resistance training: 10 to 20 hard sets per muscle group per week, with progressive overload on compound lifts.
  • Sleep: 7 to 9 hours. Nedeltcheva et al. (2010) showed that sleep-restricted dieters lost 55 percent more lean mass than rested dieters at the same calorie intake.

What to do with this calculator's number

Set the deficit. Eat it for 14 days. Track weight every morning fasted and average the seven most recent days. If the average drops at your target pace, hold. If it stalls, drop intake by 100 kcal/day or add 10 minutes of walking. If it drops too fast, add 100 kcal/day. Anchor every adjustment to your maintenance calories baseline.

Frequently asked questions

Why am I not losing weight at a 500 kcal deficit?
Three causes account for almost every stall. First, intake is under-reported (the most common cause): weigh every food in grams for one week to test. Second, the TDEE estimate is too high; see /how-accurate-is-tdee/ for the calibration method. Third, water-weight noise is hiding fat loss, so compare 7-day averages instead of daily numbers. Walk through the full checklist at /why-am-i-not-losing-weight/.
Should I have refeed days during a calorie deficit?
For cuts longer than four to six weeks, a one- or two-day refeed at maintenance helps adherence and partially counters metabolic adaptation. Trexler et al. (2018) found that planned diet breaks preserved more lean mass than continuous dieting over 16 weeks. Most lifters also report better training within 24 hours of a high-carb refeed.
How long until I start seeing calorie-deficit results?
Scale-weight changes show up within 7 to 14 days of a consistent deficit, but watch the 7-day average, not the daily reading. Visible body composition changes typically appear at four to eight weeks. The mirror lags the scale because the last fat to leave any given area often takes 12 weeks of sustained deficit.
Can I lose fat and gain muscle in a calorie deficit?
Yes if you are a beginner, returning after a layoff, overweight (above 20 percent body fat for men or 30 percent for women), or using anabolic agents. Otherwise, body recomposition is slow and rare. Lean intermediate and advanced lifters should pick a phase, either cut or bulk, and pursue it cleanly for three to four months.
Is a bigger calorie deficit always better for faster fat loss?
No. Past roughly 25 percent below TDEE, marginal returns drop sharply: hunger spikes, training suffers, sleep degrades, and adherence collapses. Garthe et al. (2011) compared 0.7 percent vs 1.4 percent weekly loss in athletes; the slower group lost the same total fat and gained 2 percent more lean mass. Slower deficits beat aggressive deficits over any timeline longer than 8 weeks.