Calorie Deficit Calculator for Fat Loss

A calorie deficit means eating fewer calories than your body burns. Enter your details to find your maintenance level, then see mild, standard, and aggressive deficit targets β€” each with an estimated weekly fat loss rate.

Mifflin-St Jeor Formula Weekly Loss Estimates Metric & Imperial

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Understanding Calorie Deficit Sizes

A calorie deficit means eating fewer calories than your body burns in a day. When you sustain a deficit, your body draws on stored fat for the missing energy β€” leading to fat loss over time. The size of the deficit determines how fast and how sustainably that happens.

Mild Deficit β€” 250 kcal/day below maintenance

A mild deficit leads to approximately 0.25 kg (0.5 lb) of fat loss per week. It is the most sustainable approach β€” least disruptive to energy levels, training performance, and hunger. Best suited for people who are new to tracking, those with low starting body fat, or athletes in a slow cut to preserve performance and muscle.

Standard Deficit β€” 500 kcal/day below maintenance

The standard deficit is the benchmark recommendation from most sports dietitians and nutrition researchers. It produces approximately 0.5 kg (1 lb) of fat loss per week β€” a rate consistent with body fat reduction with minimal muscle loss, provided protein intake is adequate (roughly 1.6–2.2 g/kg of bodyweight).

Aggressive Deficit β€” ~25% below maintenance

An aggressive deficit produces faster short-term results but carries meaningful risks: increased muscle loss, lower energy for training, hormonal disruption, and difficulty sustaining the approach. It may be appropriate for short-term phases (4–6 weeks) under professional guidance, but is not recommended as a long-term strategy.

How to Choose Your Deficit

If you are new to tracking calories: start with the mild deficit. If you have tracked before and want consistent fat loss without feeling depleted: use the standard deficit. If you are preparing for a specific event on a tight timeline: consider the aggressive deficit only for a short period. Your weekly results will tell you whether to adjust.

Deficit Tiers at a Glance
Deficit Size kcal/day Below Est. Weekly Loss
Mild250 kcalβ‰ˆ 0.25 kg / 0.5 lb
Standard500 kcalβ‰ˆ 0.5 kg / 1 lb
Aggressive~25% of TDEEβ‰ˆ 0.75–1 kg / 1.5–2 lb

The Weekly Fat Loss Formula

Approximately 7,700 kcal of energy is stored in 1 kg of body fat. A daily deficit of 500 kcal creates a weekly energy deficit of 3,500 kcal β€” translating to roughly 0.45–0.5 kg of fat loss per week. Actual results vary based on water retention, stress, sleep, and diet composition.

Track Your Fat-Loss Calories in Nutrido

The hardest part of a calorie deficit is not knowing the number β€” it is hitting it consistently, every day. Nutrido makes daily tracking fast enough to actually stick to.

Set Your Deficit Target in Nutrido

Enter your deficit calorie target directly as your daily goal in Nutrido. Set your protein target to preserve muscle during the cut β€” aim for at least 1.6 g per kg of bodyweight. Your dashboard shows your remaining budget in real time.

Log Every Meal Quickly

Photograph your food for an instant AI estimate or search the manual database. The faster logging is, the more likely you are to actually do it. Consistency in tracking β€” not perfection β€” is what produces results over weeks and months.

Adjust When Results Plateau

If weight loss slows after 2–3 weeks, your maintenance calories have likely decreased as your body adapts. Recalculate your TDEE with your new weight, and update your target in Nutrido. Small adjustments prevent plateaus from stalling your progress.

Track Your Deficit with Nutrido

Free on iOS & Android

Frequently Asked Questions

Common questions about calorie deficits, fat loss, and sustainable dieting.

What is a calorie deficit?

A calorie deficit means eating fewer calories than your body burns in a day. When you consistently consume less energy than you expend, your body draws on stored body fat to make up the difference β€” leading to fat loss over time. The size of the deficit determines how quickly this happens.

How large should my calorie deficit be?

A mild deficit of 250 kcal per day leads to approximately 0.25 kg (0.5 lb) of fat loss per week. A standard deficit of 500 kcal per day leads to roughly 0.5 kg (1 lb) per week. Deficits larger than 750 kcal per day increase the risk of muscle loss and are generally not recommended without professional guidance.

How much weight will I lose per week in a calorie deficit?

Approximately 7,700 kcal equals 1 kg of body fat. A 500 kcal daily deficit creates a 3,500 kcal weekly deficit, which leads to roughly 0.45–0.5 kg of fat loss per week. Actual results vary based on water retention, starting body fat percentage, sleep quality, stress, and diet composition.

Is a large calorie deficit dangerous?

Very low calorie diets β€” below approximately 1,200 kcal for women or 1,500 kcal for men β€” can lead to nutrient deficiencies, muscle loss, fatigue, and hormonal disruption. This calculator is not a medical tool. Consult a registered dietitian or physician before pursuing a significant calorie restriction, especially if you have any health conditions.

Why did my weight loss plateau?

As you lose weight, your maintenance calorie level decreases because there is less body mass to fuel. After significant weight loss, your original deficit is no longer sufficient to produce the same results. Recalculate your TDEE with your new weight and update your target accordingly. Also check for non-fat weight changes β€” increased water retention from stress or sodium, for example, can mask ongoing fat loss on the scale.

How does Nutrido help with a fat-loss diet?

Set your calorie deficit target as your daily goal in Nutrido and log every meal using AI photo analysis or manual search. Your daily calorie balance updates in real time so you always know how much room you have left. Nutrido also tracks protein to help you eat enough to preserve muscle while in a deficit.

Track Your Fat-Loss Calories in Nutrido

You have your deficit target. Now make it stick every day. Nutrido logs meals in seconds with AI photo analysis, tracks your running calorie balance, and helps you hit your protein to protect muscle during fat loss. Free on iOS & Android.

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🎯 Custom calorie & macro goals