Calorie Deficit Calculator

Calorie deficit calculator 2026 online. Calculate your weight loss needs and rate

This tool helps you easily calculate your daily calorie deficit needed to lose weight. Just enter your weight, height, age, gender, activity level and goal, and the calculator will show your energy needs, optimal deficit and projected rate of weight loss. This will make it easier for you to plan a healthy and effective reduction.

Who is this calculator for

The caloric deficit calculator is a tool for people who want to:

• lose weight in a controlled and healthy way,
• plan your diet and training better,
• check your daily calorie requirement,
• assess the real rate of fat tissue reduction,
• compare the effects at different levels of deficit.

What the calculator calculates

The tool displays some key information:

• Basal metabolic rate (BMR)- that is, the amount of calories needed to sustain life at rest,
• Total calorie requirement (TDEE)- that is, the calories burned during the day, taking into account activity,
• Optimal caloric deficit- usually 300-700 kcal less than TDEE,
• Weight loss rate- forecast of how much weight you can reduce per week and month.

How the calculator works

The calculator uses popular formulas (e.g. Mifflin-St Jeora) to calculate BMR, then multiplies the result by the activity factor to obtain TDEE. It then subtracts your chosen caloric deficit from this value. This allows the user to see how many calories they can consume to lose weight at a healthy rate.

The rule of thumb is that a reduction of 7,700 kcal corresponds to a decrease in body weight of approximately 1 kg. This allows you to estimate the rate of weight loss at a given deficit.

Calculation examples

Woman, 30 years old, 65 kg, 170 cm, moderate activity

BMR is approx. 1450 kcal, TDEE approx. 2200 kcal. A deficit of 500 kcal gives a diet of 1,700 kcal, which translates into a loss of approximately 0.5 kg per week.

Male, 40 years old, 85 kg, 180 cm, low activity

BMR is approx. 1800 kcal, TDEE approx. 2200 kcal. A deficit of 700 kcal gives a diet of 1,500 kcal and a loss of 0.6–0.7 kg per week.

Female, 25 years old, 55 kg, 165 cm, high activity

BMR is approx. 1350 kcal, TDEE approx. 2100 kcal. A deficit of 400 kcal gives a diet of 1,700 kcal and a loss of approximately 0.4–0.5 kg per week.

Approximate table

Practical tips

• A safe deficit is 300-700 kcal. Too much may lead to weakness and the yo-yo effect.
• Remember that training increases your TDEE - you can eat more and still lose weight.
• Don't go below your BMR - it's the minimum needed for your body to function properly.
• Spread the deficit wisely - part through diet, part through exercise.
• Be patient - a healthy reduction rate is 0.5-1 kg per week.

Frequently asked questions

Does the calculator take into account gender

Yes, the formula takes into account metabolic differences between women and men.

Is the result a guarantee of weight loss

No, the calculator shows approximate values. The effects also depend on hormones, sleep quality, stress and individual metabolism.

Is it possible to increase the deficit to 1000 kcal

Yes, but it is not recommended in the long run. Large deficits lead to a decrease in energy and the risk of deficiency.

Does the calculator also calculate caloric surplus

Yes, just add the calories to the TDEE instead of subtracting them. Then you will see how much you need to eat to gain weight.

Most common errors

• Not providing the correct activity - overstates or underestimates the result.
• Cutting calories below your BMR, which is unhealthy.
• Exaggerated Expectations - Rapid weight loss is rarely sustainable.

Health and Safety

Calculate your deficit now