Calorie Deficit Calculator - Lose Fat Without Losing Muscle
Not sure how many calories to cut per day to lose 1kg per week or something more sustainable? This safe calorie deficit calculator turns your TDEE and goal into a daily calorie target, an estimated timeline, and a protein recommendation built specifically forcutting calories while preserving muscle. It also works forUK calorie deficit calculations because kcal units are the same globally.
Protein Target to Preserve Muscle
— g / day
Estimated Timeline
Log your weight and calories in Sleet to see whether your actual rate of loss matches this target.
Cutting Calories Calculator for Muscle Preservation — The Method
One kilogram of body fat is roughly equivalent to 7,700 calories. This calorie deficit calculator uses that relationship to convert your chosen weekly weight loss rate into a daily calorie deficit, then subtracts it from your TDEE to give you a concrete daily target.
Why Bigger Deficits Aren't Always Better
A deficit above roughly 25% of your TDEE increases the proportion of weight lost from muscle rather than fat, tanks training performance, and is much harder to sustain for more than a few weeks. This calculator flags when your selected goal pushes you past that threshold so you can choose a more sustainable rate if needed.
Why Protein Intake Matters More in a Deficit
When calories are restricted, your body is more likely to break down muscle tissue for energy unless protein intake is high enough to signal it should be preserved. Lifting while in a deficit, combined with 1.8–2.2g of protein per kg of bodyweight, is the single most effective combination for keeping the weight you lose mostly fat.
What Is My Calorie Deficit?
Your calorie deficit is simply your maintenance calories (TDEE) minus your daily calorie intake. If your TDEE is 2,400 kcal and you eat 1,900 kcal, your calorie deficit is 500 kcal per day. Over a week, that is a 3,500 kcal deficit.
How to Figure Out Calorie Deficit, Step by Step
Step 1: calculate your maintenance calories using ourTDEE calculator. Step 2: choose a weekly loss target based on your risk tolerance and training demands. Step 3: convert that target into daily deficit with (weekly kg loss x 7,700) / 7. Step 4: subtract the result from TDEE. This gives your daily calorie target for fat loss.
Calorie Deficit Calculator UK, Does Anything Change?
No meaningful changes are needed. UK food labels and most global nutrition labels use kcal, so the calculation is identical. The only thing that changes is food tracking habits, not the maths.
If your goal is to keep progressing in the gym while cutting, readprogressive overload in a calorie deficitfor realistic expectations and programming adjustments.
Calorie Deficit Calculator — Frequently Asked Questions
What is my calorie deficit?
Your calorie deficit is the difference between your TDEE and your calorie intake. If your TDEE is 2,500 kcal and you eat 2,000 kcal, your deficit is 500 kcal per day.
How to figure out calorie deficit manually?
Find your TDEE first, choose a weekly fat loss goal, convert it into a daily deficit with (weekly kg loss x 7,700) / 7, then subtract that from TDEE.
How do I calculate a calorie deficit to lose fat without losing muscle?
Subtract 300–500 calories from your TDEE for a moderate deficit, keep lifting, and eat 1.8–2.2g of protein per kg of bodyweight. This calculator does the maths for four different loss-rate targets automatically.
How many calories should I cut per day to lose 1kg per week?
Roughly 1,100 calories per day, since 7,700 calories equal about 1kg of fat. This is an aggressive deficit best used short-term.
What is a safe calorie deficit for fat loss?
Generally 15–25% below TDEE, or roughly 300–750 calories per day for most people. Deficits beyond 25% increase muscle loss risk and hurt training performance.
How much protein do I need when cutting calories to preserve muscle?
1.8–2.2g per kg of bodyweight per day if strength training, or 1.6–1.8g per kg if not currently lifting.
How long does it take to lose weight on a calorie deficit?
At a 500-calorie daily deficit, expect roughly 0.45kg per week — a 10kg goal takes approximately 22 weeks. Smaller deficits take longer but better preserve muscle.
Does this calorie deficit calculator work in the UK?
Yes. It uses kcal, which is the same unit used on UK nutrition labels and internationally, so the results are valid for UK users.
What makes a good calorie deficit calculator for fat loss?
A good calculator should use your TDEE, show multiple fat loss rates, warn about overly aggressive deficits, and include a protein target to help preserve muscle.
Track Calories and Training Together
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