MasterTool

Calorie Deficit Calculator

Set a daily calorie deficit against your maintenance calories and see your target intake and projected weekly weight change.

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What this tool does

Set a daily calorie deficit against your maintenance calories and see your target intake and projected weekly weight change. The 3,500 kcal-per-pound figure is a long-standing rule of thumb; real loss slows as body weight and activity change. Deficits that take intake below BMR or below ~1,200/1,500 kcal should only be used under professional supervision — this tool flags very low targets.

How to use the Calorie Deficit Calculator

  1. Enter or select body weight in lb.
  2. Enter or select height in in.
  3. Enter or select age (years).
  4. Enter or select equation sex coefficient.
  5. Enter or select activity level.
  6. Enter or select daily calorie deficit (kcal).
  7. Read the calculated result; change any measurement to compare alternatives.

Formula

target intake = TDEE − deficit; projected weekly loss ≈ deficit × 7 / 3,500 kcal per lb (rule of thumb, labelled as such)
weight
Body weight (lb, before metric conversion)
height
Height (in, before metric conversion)
age
Age (years)
sex
Equation sex coefficient
activity
Activity level
deficit
Daily calorie deficit (kcal)

The 3,500 kcal-per-pound figure is a long-standing rule of thumb; real loss slows as body weight and activity change. Deficits that take intake below BMR or below ~1,200/1,500 kcal should only be used under professional supervision — this tool flags very low targets.

Worked example

For calorie deficit calculator, the following measurements illustrate the exact method: Body weight: 150; Height: 67; Age (years): 30; Equation sex coefficient: male; Activity level: 1.55; Daily calorie deficit (kcal): 500.

Inputs

  • Body weight150 lb
  • Height67 in
  • Age (years)30
  • Equation sex coefficientMale (+5)
  • Activity levelModerately active (exercise 3–5 days/week)
  • Daily calorie deficit (kcal)500

Result

  • Target daily intake (kcal)1,978.47
  • Maintenance calories (kcal/day)2,478.47
  • Projected weekly loss (lb, rule-of-thumb)1

Results explained

Target daily intake (kcal)
Target daily intake (kcal) from the formula above. The 3,500 kcal-per-pound figure is a long-standing rule of thumb; real loss slows as body weight and activity change. Deficits that take intake below BMR or below ~1,200/1,500 kcal should only be used under professional supervision — this tool flags very low targets.
Maintenance calories (kcal/day)
Maintenance calories (kcal/day) from the formula above. The 3,500 kcal-per-pound figure is a long-standing rule of thumb; real loss slows as body weight and activity change. Deficits that take intake below BMR or below ~1,200/1,500 kcal should only be used under professional supervision — this tool flags very low targets.
Projected weekly loss (lb, rule-of-thumb)
Projected weekly loss (lb, rule-of-thumb) from the formula above. The 3,500 kcal-per-pound figure is a long-standing rule of thumb; real loss slows as body weight and activity change. Deficits that take intake below BMR or below ~1,200/1,500 kcal should only be used under professional supervision — this tool flags very low targets.

Frequently asked questions

Eating fewer calories than your maintenance (TDEE) level. The gap is the deficit — e.g. maintenance 2,400 kcal with a 500 kcal deficit means a 1,900 kcal/day target.

A common sustainable range is 250–750 kcal/day. Larger deficits lose weight faster on paper but are harder to sustain and risk muscle loss and under-fuelling; very low intakes need medical supervision.

It approximates the energy stored in a pound of body fat. It is a rule of thumb for early projections — real-world loss is not linear and slows over time, so treat projections as rough guides.

Water shifts, activity changes, intake tracking error and metabolic adaptation all bend the curve. Judge by the 3–4 week trend, not single weigh-ins, and review with a professional if progress stalls completely.

Eating below BMR for extended periods is generally discouraged without supervision. If the calculator's target lands below your BMR, consider a smaller deficit.