Calorie deficit calculator
Pick a goal weight and a pace. It works out your maintenance calories, takes the matching deficit off, and tells you how long the cut will take. It won't go below a sensible minimum intake.
Calorie Deficit Calculator
A calorie deficit of about 500 kcal a day loses roughly 0.45 kg (1 lb) a week, because a kilo of body mass holds about 7,700 kcal. A sustainable pace is 0.5 to 1 percent of bodyweight a week. Faster than that costs more muscle. Men should rarely eat below 1,500 kcal a day, and women below 1,200, without supervision.
Optional. Switches maintenance to Katch-McArdle.
451 kcal below maintenance
Method notes (3)
- Using Mifflin-St Jeor — Katch-McArdle would need body_fat_pct
- Activity multiplier 1.55 (moderate)
- Maintenance falls as you lose weight, so recalculate every 4-5 kg or the deficit quietly shrinks.
Metric or imperial · runs the same code as the app · nothing is sent anywhere
How it works
Maintenance is the TDEE calculator's figure: Mifflin-St Jeor, or Katch-McArdle when body fat is given, times the activity multiplier. The deficit is bodyweight × weekly % × 7700 / 7, using 7,700 kcal per kilo of body mass lost, and it is subtracted from maintenance.
The intake never goes below 1,500 kcal for men or 1,200 for women. If the pace you asked for would go lower, it is capped and the weeks are worked out from the capped deficit. Weeks to goal is (current − goal) / weekly loss. The macros below are the cut split, with protein raised to protect muscle.
Common questions
How fast should I lose weight?
Half to one percent of bodyweight a week works for most people. Leaner people should stay near the low end, because the leaner you are the more muscle a fast cut takes with it. People with a lot to lose can go faster at first.
Why did my weight loss stall?
Maintenance falls as you get lighter, so the same intake gives a smaller deficit over time. Water swings can also hide fat loss for a week or two. Recalculate every 4 to 5 kg and judge the trend over at least two weeks.
Is 1,200 calories enough?
For a small, sedentary woman it can be the right number. For most men and active women it is too low to get enough protein and micronutrients, and it makes training much harder. A slower pace you can stick to beats a fast one you abandon.
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The app runs this same maths against your logged weigh-ins, meals and sessions, so the figure updates itself instead of being a one-off.
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