Calorie Deficit Calculator
Free calorie deficit calculator: goal weight, pace and TDEE in — daily target, deficit size and timeline out. Safety-flagged, private, instant.
—
3,500 kcal ≈ one pound of body fat (the classic approximation). Consult a professional before aggressive or extended deficits — see the disclaimer for the full honest version.
A calorie deficit is the only mechanism weight loss has: consume less than you burn, and the body makes up the difference from stored energy. The calculator's job is to turn two warm feelings — "I want to weigh X" and "by summer" — into one cold, usable number: a daily calorie target.
The 3,500 kcal-per-pound approximation that powers the math is old and imperfect (water weight, metabolic adaptation and body composition all bend it), but as a planning instrument it remains the standard: a 500 kcal daily deficit lands at very roughly a pound a week. Pick a pace you can actually sustain — the calculator's safety line exists because aggressive deficits fail in a specific way: hunger compounds, adherence breaks, and the rebound erases the loss.
Two honest recommendations. First, start slower than feels productive: 0.5 lb/week with perfect adherence beats 2 lb/week abandoned in week three. Second, recompute as you go — TDEE falls as you lose weight, and a target set in January quietly becomes a maintenance number by April. Pair the output with one of the tracker apps we compared — the deficit is the plan; the app is the daily execution.
Frequently asked questions
What is a safe calorie deficit?
Commonly cited floors are around 1,200 kcal/day for women and 1,500 for men, with 500 kcal/day deficits as the standard sustainable pace — the calculator flags targets below the floor. A professional should supervise anything aggressive.
How long will my deficit take?
Type your numbers above: the timeline is (pounds to lose × 3,500) ÷ daily deficit. A 15-pound goal at 1 lb/week is about 15 weeks — plan refeeds and plateaus inside that estimate.
Why did my weight loss stop?
TDEE falls as you lose weight (a smaller body burns less), adaptation reduces it further, and logging drift creeps in. Recompute your target every 10-15 pounds — the calculator takes two seconds.
Should I do cardio to increase my deficit?
Only if you like it — exercise burns less than people hope (a 30-minute jog is roughly one muffin) and boosts appetite. Deficit by food, cardio for heart and mood, weights for keeping muscle: the division of labor that actually works.
Do refeed days or diet breaks help?
Structured diet breaks (a week at maintenance every 6-8 weeks) show modest adherence and hormone benefits in studies without harming fat loss. They are scheduled maintenance, not falling off the plan — budget them in the timeline.