FitForge

Calorie Deficit Calculator

Choose a goal weight and a pace. You get a daily calorie target and an honest timeline that accounts for your maintenance calories falling as you lose weight.

Units
Sex
yrs
lb
Height
ft
in
lb

Eat this per day

2,080kcal

TDEE 2,740 − 660 kcal deficit

Time to goal

15weeks

Simple math says

14weeks

If TDEE never changed

Plan the cut with an assistant

Ask how to structure the deficit around your training, what to do at a plateau, or how to keep strength while cutting.

Uses AI. Answers can be wrong; check anything important.

Why the last kilos come off slower

Losing weight lowers your maintenance: a lighter body costs less to run and to move. If you keep eating the same amount, your deficit quietly shrinks every week. Step through the weeks and compare the curve with the straight "3,500 calories per pound" line.

Weight

176.4lb

Maintenance now

2,740kcal

Real deficit

660kcal / day

The blue line flattens because the deficit shrinks, not because your body is "in starvation mode". The fix is simple: recalculate every few weeks and trim intake or add steps to restore the gap.

How the target is set

Your maintenance comes from the Mifflin-St Jeor equation times your activity factor (see the TDEE calculator). The deficit is sized from your chosen pace: losing 0.75% of bodyweight a week needs about 7,700 kcal per kilogram of fat, spread over seven days. The projection then simulates each week, re-computing maintenance at your new weight.

Pace guidance: 0.5% a week is gentle and easy to hold; 1% is aggressive but workable for people with more to lose. Faster than that and research on athletes (for example Garthe et al., 2011) shows more lean mass lost alongside the fat.

Questions lifters ask

How big should my calorie deficit be?

For most people, 15–25% below maintenance, which usually means 300–700 kcal a day. That produces about 0.5–1% of bodyweight loss per week, fast enough to see progress and slow enough to keep muscle and training performance.

Is 3,500 calories really one pound of fat?

It is a reasonable rule of thumb for fat tissue (about 7,700 kcal per kilogram), but it overpredicts long-term loss because your maintenance calories fall as you get lighter. This calculator re-computes your TDEE every week to account for that.

What is the lowest safe calorie intake?

General guidance, including from the NIH, is not to go below about 1,200 kcal a day for women or 1,500 for men without medical supervision. This calculator warns you if a target falls under those figures.

Why did my weight loss stall?

Common reasons: your TDEE fell as you lost weight, portions crept up, or water retention is hiding fat loss. Compare weekly averages rather than daily weigh-ins, and recalculate your deficit after every 4–5 kg lost.

Keep calculating