Calculators / Calorie deficit calculator
Calorie deficit calculator
A calorie deficit calculator turns a weekly rate into a daily number below maintenance. This one runs MacroDiet's v2 algorithm and shows the two guardrails most calculators leave out — the 35% cap and the calorie floors — and what they cost when they fire.
Also on macrodiet.fit in six languages — same formula, same numbers.
rate = 85 kg × 0.5% = 0.425 kg/week
daily change = 0.425 × 7,700 ÷ 7 = 468 kcal (cap 993)
target = 2,837 − 467 = 2,370
How the math works
- Maintenance — Mifflin-St Jeor BMR × activity multiplier = TDEE (calorie calculator). Example: 2,837 kcal.
- Rate to kcal — weekly kg = body weight × rate%, then daily = weekly kg × 7,700 ÷ 7. Example: 85 × 0.5% = 0.425 kg, 0.425 × 7,700 ÷ 7 = 467 kcal.
- Cap — the daily change cannot exceed 35% × TDEE (993 kcal for the example). Above it, the calculator reports DELTA_CAPPED and uses the cap.
- Floor — on a cut the target is held at 1,500 kcal (men) / 1,200 kcal (women); the lower mode uses 1,200 / 1,000. Below it, CALORIE_FLOOR_APPLIED — and the delivered rate is slower than the one selected.
- Protein bump — on a cut the protein tier gets +0.2 g/kg before the split, so the macro cards under the result show more protein than the same tier at maintenance.
The three rates for the example
| Rate | % of body weight / week | kg / week | Daily deficit | Target | Protein (1.6 + 0.2 g/kg) |
|---|---|---|---|---|---|
| Conservative | 0.3% | 0.255 | −280 kcal | 2,557 kcal | 153 g |
| Moderate | 0.5% | 0.425 | −467 kcal | 2,370 kcal | 153 g |
| Aggressive | 0.75% | 0.638 | −701 kcal | 2,136 kcal | 153 g |
When the guardrails fire
75 kg, 165 cm, 30, female, sedentary, aggressive rate: TDEE 1,691; requested 619 kcal/day → capped to 592 (35% of TDEE) → target 1,099 → raised to the 1,200 kcal floor. Delivered rate 0.45 kg/week instead of the 0.56 kg asked for. Aggressive settings always come with their cost printed next to them — that is the point of showing the trace.
What the numbers are not
7,700 kcal per kg is a rounded convention for the energy in a kilogram of body fat, not a promise about what a scale will show; water, glycogen and food in transit move day-to-day weight by more than a day's deficit. The floors and cap are the algorithm's rules for producing a coherent target, not medical thresholds, and nothing here is a prescription. This is arithmetic, not medical advice.
Frequently asked
What is a calorie deficit?
Eating less energy than the body uses, so the difference comes from stored energy. In the calculator it is a number: TDEE minus the daily target. For the 85 kg example at the moderate rate, TDEE is 2,837 kcal, the deficit 467 kcal, the target 2,370 kcal.
How much of a calorie deficit is safe?
"Safe" is a medical judgement this calculator does not make. What it does have is three guardrails from the MacroDiet algorithm: the rate is at most 0.75% of body weight per week; the daily change is capped at 35% of TDEE; and the target is never set below 1,500 kcal for men or 1,200 kcal for women (a lower mode allows 1,200 / 1,000). When a guardrail fires the calculator says so and shows what it cost. Whether any rate is right for a particular person is a question for a qualified professional.
How much weight can I lose per week?
The calculator offers three rates as a share of body weight: 0.3%, 0.5% and 0.75% per week — at 85 kg that is 0.26, 0.43 and 0.64 kg. Those are the rates the arithmetic aims at using the 7,700 kcal/kg convention; scale weight moves with water and food as well as tissue, which is why MacroDiet reads a smoothed trend rather than single weigh-ins.
Should I calculate my deficit daily or weekly?
The algorithm computes a daily number and it is the same budget either way: 467 kcal/day × 7 = 3,269 kcal/week for the example. The daily figure is what a food log is compared against; the weekly one is useful for seeing that one higher day does not undo the week.
What happens with an extreme calorie deficit?
This calculator will not produce one. Ask for an aggressive rate on a small, sedentary frame — 75 kg, 165 cm, 30, female, sedentary — and the requested 619 kcal/day is first capped at 35% of a 1,691 kcal TDEE (592 kcal), then the 1,099 kcal target is raised to the 1,200 kcal floor. The cost is shown, not hidden: the delivered rate is 0.45 kg/week instead of the 0.56 kg asked for. What very low intakes do to a body is a medical topic we do not cover.
Can I exercise while in a calorie deficit?
The calculator has no opinion on the day's training; training enters only through the activity level, which sets the multiplier and therefore TDEE. If training days change, change the level and the deficit is recomputed from the new TDEE. What a cut does to training performance is a coaching question — the Zyra Workouts side of this site covers progression, not diet.
What if my weight loss stalls?
Two mechanical things to check before anything else. First, the inputs: at 80 kg the same person's TDEE is 2,759 kcal rather than 2,837, so a target set at 85 kg is a smaller deficit five kilos later — recompute. Second, the signal: a two-week flat line in a trend weight is different from two flat weigh-ins. MacroDiet compares logged intake to the trend, which is a better basis for adjusting than the estimate alone.
Related calculators
Track against these targets
MacroDiet's own calculators run this exact v2 formula, and the same zyra-algo engine sets the targets inside the app — where logged food is compared against them and the dashboard shows the weight trend. Web app, live at macrodiet.fit — nothing to install.
Zyra is a training and nutrition tracking tool. Nothing on this page is medical advice, a diagnosis, or an individual prescription. The numbers are estimates from published formulas and the apps' own rules — consult a qualified professional for decisions about your health, and a coach for your training.