Calculator Tools
Calorie Deficit Calculator
Calculate your daily calorie deficit, target intake, and weekly rate to lose or gain weight by a date or in a set number of weeks.
Unit system
Kilograms and centimeters.
Your details
14 to 120.
Biological sex
Mifflin-St Jeor uses a sex-based constant.
Activity level
Your goal
Set this lower than current for a deficit, higher for a surplus.
Timeframe
12 weeks is a common starting plan. Range: 1 to 520.
Your plan
Target daily intake
1,777 kcal
Eat this many kcal per day to lose weight on schedule.
Daily deficit
-642 kcal/day
Difference from your TDEE of 2,418 kcal/day.
Total weight change
-7 kg
15.4 lb
Timeframe
12 weeks
Finish around August 31, 2026.
Weekly rate
-0.58 kg/wk
1.29 lb/wk
TDEE (maintenance)
2,418 kcal
BMR 1,759 x 1.375
Reference rates
| Daily change | Weekly loss | Pace |
|---|---|---|
| -250 kcal/day | ~0.23 kg / 0.5 lb | Mild deficit. Easy to sustain. |
| -500 kcal/day | ~0.45 kg / 1 lb | Classic dieting pace. Common default. |
| -750 kcal/day | ~0.68 kg / 1.5 lb | Aggressive. Higher risk of muscle loss. |
| -1000 kcal/day | ~0.91 kg / 2 lb | Upper boundary unsupervised plans should stay within. |
| +250 kcal/day | ~0.23 kg / 0.5 lb gain | Lean bulk pace. |
| +500 kcal/day | ~0.45 kg / 1 lb gain | Standard bulking surplus. |
Numbers use the 7700 kcal/kg (3500 kcal/lb) planning rule. Real weight change is non-linear because of water, glycogen, and metabolic adaptation. This calculator is for general planning and is not medical advice.
How to use
- Pick your unit system (metric or imperial). Switching units converts existing values automatically.
- Enter your age, biological sex, current weight, and height.
- Select your activity level. Most people who train a few times a week fall between Lightly active and Moderately active.
- Enter your goal weight. Set it lower than current for a deficit, higher for a surplus.
- Choose a timeframe: By weeks (e.g. 12 weeks), By target date (event or vacation), or By weekly rate (e.g. 0.5 kg per week).
- Read the target daily intake, the deficit or surplus, the weekly rate, and the estimated finish date in the plan card.
- Tap Copy summary to save the result, or Reset to start over.
About this tool
Calorie Deficit Calculator turns a weight goal into a concrete daily calorie plan. Enter your age, sex, height, current weight, and activity level, then set a goal weight and a timeframe (weeks to goal, target date, or weekly rate). The tool computes your Basal Metabolic Rate with the Mifflin-St Jeor equation (the formula used in modern clinical and sports practice), multiplies it by the standard activity factor (1.2 sedentary, 1.375 light, 1.55 moderate, 1.725 very active, 1.9 extra active) to estimate Total Daily Energy Expenditure, and then back-solves for the daily kcal deficit or surplus required to reach the goal on schedule using the 7700 kcal per kilogram (3500 kcal per pound) planning rule. The plan card shows the target daily intake to eat each day, the daily deficit or surplus compared with maintenance, the total weight change, the weekly rate of change, and an estimated finish date. If the plan exceeds a 1000 kcal per day deficit or pushes intake below the conservative 1200 kcal (female) or 1500 kcal (male) floor, a safety note suggests a longer timeframe or a smaller goal change. A reference table maps common deficits and surpluses (250, 500, 750, 1000 kcal per day) to weekly weight changes in both kilograms and pounds. The math is transparent and runs locally in your browser; nothing you type is uploaded. Useful for cutting, lean bulking, planning a vacation cut, hitting a wedding weight, reverse dieting, or simply checking whether a popular online plan is realistic. This is a general planning tool and not medical advice; consult a qualified professional for clinical or athletic guidance.
Free to use. Works in your browser. No signup, no login.
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