Free Calorie Deficit Calculator for Weight Loss
Use the best free calorie deficit calculator to estimate your daily needs. Whether you need a calorie deficit calculator for women or men, this tool calculates your exact TDEE using NHS-aligned formulas. No app download or signup required, 100% private.
Personal Information
Settings
Your Calorie Profile
Goal-Based Adjustments
How to Use the Calculator
This tool estimates your Basal Metabolic Rate (BMR) — the calories your body burns at complete rest — and your Total Daily Energy Expenditure (TDEE), which factors in your activity level. Follow these steps. For a deeper dive into the math, read our complete guide on calculating your TDEE and BMR.
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Select Unit System: Choose between Metric (kg, cm), US (lb, ft/in), or Imperial (lb, cm) at the top of the calculator.
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Enter Personal Info: Input your age, select your gender, and enter your height and weight.
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Set Activity Level: Choose the option that best represents your daily exercise and work habits to calculate your TDEE.
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Adjust Settings (Optional): Under "Settings", select your preferred BMR formula. If you choose "Katch-McArdle," a new field will appear asking for your Body Fat Percentage (you can find this using our body fat calculator).
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Calculate: Click the "Calculate Calories" button to view your BMR, TDEE, and goal-based adjustments for weight loss or muscle gain.
BMR Equations
Female: BMR = 10 × W + 6.25 × H − 5 × A − 161
W = weight (kg), H = height (cm), A = age (years)
Published in 1990, this is considered the most accurate formula for estimating BMR in the general population. It tends to be more accurate than Harris-Benedict for overweight and obese individuals.
Female: BMR = 447.593 + 9.247 × W + 3.098 × H − 4.330 × A
Originally published in 1919 and revised by Roza and Shizgal in 1984. Historically the most widely used BMR formula, though it can overestimate by ~5% for obese individuals compared to Mifflin-St Jeor.
LBM = W × (1 − BF / 100)
W = weight (kg), BF = body fat %, LBM = lean body mass (kg)
Unlike the other formulas, Katch-McArdle accounts for lean body mass rather than total body weight, making it more accurate for individuals who know their body fat percentage (which you can measure with our body fat calculator). It is gender-independent.
Food Energy Converter
Convert between common food energy units used on nutrition labels worldwide. The large Calorie (Cal or kcal) is the standard on most food packaging. Kilojoules (kJ) are used in Australia, New Zealand, Europe, and many other regions. Enter a value and select units to convert instantly.
| Unit | Equivalent | Region / Use |
|---|---|---|
| 1 kcal | 4.184 kJ | US, Canada, most labels |
| 1 kJ | 0.2390 kcal | EU, Australia, NZ |
| 1 cal (thermo) | 4.184 J | Scientific use (small cal) |
| 1 Wh | 0.8604 kcal | Electrical energy context |
| 1 BTU (th) | 0.2522 kcal | Heating / HVAC context |
Frequently Asked Questions (FAQ)
Is this the best free calorie deficit calculator for weight loss?
Yes, we believe this is the best free calorie deficit calculator because it uses the clinically validated Mifflin-St Jeor formula to accurately calculate your TDEE and BMR. It is 100% free, requires no signup, and provides instant, precise targets for weight loss.
Can I use this as a calorie deficit calculator for women?
Absolutely. This calculator works perfectly for both men and women. The mathematical formulas used to calculate BMR and TDEE account for gender differences, ensuring highly accurate calorie targets whether you are male or female.
Does this compare to the NHS calorie deficit calculator?
Yes. The NHS recommends creating a daily calorie deficit of 500 to 600 calories for sustainable weight loss. Our calculator aligns with these NHS guidelines by calculating your exact Total Daily Energy Expenditure (TDEE) and allowing you to subtract a precise deficit to reach your goals safely. If you prefer a low-carb approach to dieting, you might also like our keto macro calculator.
Do I need a calorie deficit calculator app?
No, you do not need to download a calorie deficit calculator app. Our tool is fully web-based and works instantly in your browser on any phone, tablet, or computer. This saves storage space on your device while keeping your health data 100% private.
Can I use this as a calorie deficit calculator by date?
While this tool calculates your daily calorie deficit, you can easily use the results to plan for a specific date. For example, if your goal is to lose 10 lbs, and the calculator tells you to eat 500 calories below your TDEE, you know you will lose roughly 1 lb per week. You can then map that timeline to your target date.
Which BMR formula is the most accurate?
The Mifflin-St Jeor equation is generally considered the most accurate formula for the general population today. However, if you know your exact body fat percentage (which you can find using our body fat calculator), the Katch-McArdle formula is often more accurate because it relies on lean body mass rather than total body weight.
How large should my calorie deficit be?
A standard and safe calorie deficit for sustainable weight loss is about 500 calories per day, which typically results in losing about 1 pound (0.5 kg) per week. To see how this weight loss affects your overall body mass, you can use our BMI calculator. Larger deficits can lead to faster weight loss but may cause muscle loss, nutrient deficiencies, and fatigue. To learn more, read our guide on how many calories you should eat to lose weight.
Is it safe to eat below my BMR?
Eating below your BMR is generally not recommended without medical supervision. Your BMR represents the energy your body needs just to keep your organs functioning while at rest. Consistently eating below this number can slow down your metabolism and lead to health complications.
Why is my TDEE higher than my BMR?
Your BMR is the energy burned doing absolutely nothing (like lying in bed all day). Your TDEE is your BMR plus the calories you burn through daily activities, exercise, and digesting food. Unless you are in a coma, your TDEE will always be higher than your BMR.
Does this calculator save my health data?
No. This is a privacy-first tool. All calculations are performed directly in your browser. We do not collect, store, or transmit your age, weight, or any other personal information.