Nutrition · Free calculator

Calorie Deficit Calculator

See how big your calorie deficit needs to be for a target weekly fat loss rate — and whether that rate is sustainable for your body size.

Short answer

Calorie Deficit Calculator

1,900Daily calorie target

Sustainable. A deficit of 21% of maintenance is in the range most people can hold for 8–16 weeks. Heavier bodies tolerate larger absolute deficits; the percentage of body weight lost per week is the honest guardrail.

How it's calculated: 500 kcal/day below maintenance — 0.5% of body weight per week. Adjust the inputs below to recalculate for your own numbers.

Disclaimer: Educational estimate only — not medical advice, diagnosis, or treatment. Population formulas do not account for your individual physiology, medications, or medical history. Discuss any health decision with a licensed clinician, and seek immediate care for urgent symptoms.

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2,400
200
1
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Formula used

Deficit from the 3,500 kcal per pound rule

A pound of body fat stores roughly 3,500 kcal. The rule overstates long-run loss because metabolism adapts, but it is a solid starting target for the first 8–12 weeks.

Daily deficit = (target lb/week × 3,500) ÷ 7 · Intake = TDEE − deficit
1 lb fat
≈3,500 kcal
Safe rate
0.5–1% BW/wk
Max useful deficit
~25% TDEE
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Why the scale stalls

Adaptive thermogenesis, water retention from training stress, and unlogged calories all blunt the theoretical rate. A stall under three weeks is usually water; beyond that, either intake has crept up or maintenance has fallen, and both call for a recalculation.

  • Weigh daily and compare 7-day averages, never day to day.
  • Diet breaks at maintenance every 8–12 weeks improve adherence.
  • Keep protein high and lift — the deficit decides how much of the loss is muscle.

FAQ

Is a 1,000 calorie deficit safe?

It can be for a heavier person with a high maintenance, but for someone maintaining at 2,000 kcal it means eating 1,000 kcal a day — too low for adequate nutrition. Judge the deficit as a percentage of maintenance, not an absolute.

How long should I stay in a deficit?

Most people do well with 8–16 week blocks followed by 1–2 weeks at maintenance before resuming.

Why am I not losing weight in a deficit?

The most common causes are underestimated intake, an overestimated TDEE, and water retention. Track precisely for two weeks before changing calories.

How this calculator is built

Independently maintained

Written by Sam Doshi and the RevenueLab editorial team. We don't sell the data feeds this tool is built on.

Sourced from primary data

Benchmarks come from public AdSense / Stripe / IRS disclosures and reader-submitted data — never third-party "$X per view" claims. Full methodology.

Last editorial review

Reviewed on a rolling quarterly cycle. Dated reviews are published on the methodology record for each calculator.

Editorial standards

See our editorial policy and disclaimer. Results are estimates, not advice.

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