Calorie Deficit Calculator

Updated Sep 2026 Used 690 times

Calculation scenario

Choose the calculation you want to perform.

Sex used by the equation

The published Mifflin-St Jeor equation uses sex-specific constants.

Age

Supported base range: 18 to 100 years.

Height

Supported base range: 1.2 to 2.3 m.

Current weight

Supported base range: 30 to 300 kg.

Typical activity level

Activity multipliers are broad estimates; day-to-day expenditure varies.

Daily calorie deficit

Supported base range: 0 to 1500 kcal.

Target weight

Supported base range: 30 to 300 kg.

Timeframe

Supported base range: 1 to 260 weeks.

Guest calculations stay on this device. Signed-in results sync privately.

Your result

Estimated daily calorie target

Enter your values, then calculate to see a verified result.

Inputs usedReview the information used for this result.

Full calculation and sourcesReview the equation, normalized inputs, assumptions, and version.

Versioned calculationFormula v3.0.0

What is estimated

Resting energy, maintenance calories, and a starting intake for the selected scenario.

Method supported

Mifflin-St Jeor resting energy, one visible activity multiplier, and a linear 7,700 kcal/kg goal scenario.

Important limitation

The goal timeline cannot predict metabolic adaptation, water change, adherence, or individual energy expenditure.

Estimate resting energyApply the Mifflin-St Jeor equationWeight, height, age, and sex coefficient

Estimate maintenanceMultiply resting energy by activityRMR x activity factor

Apply the deficitSubtract the selected daily amountMaintenance - deficit

Estimate maintenanceCalculate resting energy and apply activityMifflin-St Jeor x activity factor

Define the scenarioCompare current and target weightWeight change over selected weeks

Show the static estimateApply 7,700 kcal per kilogramNot a dynamic body-weight forecast

Interpretation

The selected scenario estimates .

A negative change is a deficit, near zero is maintenance, and a positive change is a surplus.

Review a consistent multi-week trend before changing the target.

Use this result

Weight Loss Timeline CalculatorTranslate a selected energy gap into a labeled linear timeline.Calorie CalculatorApply an explicit percentage above or below maintenance.TDEE CalculatorEstimate maintenance energy after applying activity once.

Keep exploring

Method and test recordFormula v3.0.0

Recorded scope: Adult Mifflin-St Jeor resting-energy estimate, one activity multiplier, and linear calorie-change scenarios
Publisher: CalculatorGeek
Recorded review date: 2026-09-10
Next source review: 2027-09-10
Definition fixtures: 6 configured scenarios
Published examples: 6 shown below

Recorded method

The team checked Mifflin-St Jeor constants, unit normalization, activity-factor application, sign convention, loss/maintenance/gain branches, and linear timeline arithmetic.

These records describe the published model and reference tests. A test-case count is not a certification of every possible input or an independent specialist review. Editorial policy

Known limitations

Resting energy and maintenance calories are estimates; individual expenditure can differ.
Activity multipliers are broad planning assumptions and are applied once.
The 7,700 kcal/kg timeline is linear and does not model adaptation, water change, or adherence.
The tool is intended for adults and is not medical or individualized nutrition advice.

Method sources

Latest model update

2026-09-09 - Imported the final primary-page copy and complete six-article content cluster from the September 9 Markdown package without altering calculator logic.

Reference inputs and expected results

These published examples are separate from the configured definition fixtures and any additional automated assertions. Expected values use the stated output units; invalid inputs are intended to be rejected.

Case	Inputs	Expected result
Direct deficit male metric	{"scenario":{"value":"direct"},"sex":{"value":"male"},"age":{"value":30,"unit":"years"},"height":{"value":170,"unit":"cm"},"weight":{"value":70,"unit":"kg"},"activity":{"value":"moderate"},"daily_deficit":{"value":500,"unit":"kcal"}}	{"resting_energy":1617.5,"maintenance_calories":2507.1,"target_calories":2007.1,"daily_calorie_change":-500,"weekly_weight_change":-0.45}
Linear loss package example	{"scenario":{"value":"goal"},"sex":{"value":"male"},"age":{"value":30,"unit":"years"},"height":{"value":176,"unit":"cm"},"weight":{"value":90,"unit":"kg"},"activity":{"value":"light"},"target_weight":{"value":80,"unit":"kg"},"timeframe_weeks":{"value":20,"unit":"weeks"}}	{"goal_weight_change":-10,"daily_calorie_change":-550,"weekly_weight_change":-0.5}
Maintenance goal	{"scenario":{"value":"goal"},"sex":{"value":"female"},"age":{"value":35,"unit":"years"},"height":{"value":165,"unit":"cm"},"weight":{"value":65,"unit":"kg"},"activity":{"value":"light"},"target_weight":{"value":65,"unit":"kg"},"timeframe_weeks":{"value":12,"unit":"weeks"}}	{"goal_weight_change":0,"daily_calorie_change":0,"target_calories":1849.7}
Gain goal is labeled as surplus	{"scenario":{"value":"goal"},"sex":{"value":"male"},"age":{"value":30,"unit":"years"},"height":{"value":180,"unit":"cm"},"weight":{"value":80,"unit":"kg"},"activity":{"value":"moderate"},"target_weight":{"value":84,"unit":"kg"},"timeframe_weeks":{"value":20,"unit":"weeks"}}	{"goal_weight_change":4,"daily_calorie_change":220,"weekly_weight_change":0.2}
Imperial equivalence	{"scenario":{"value":"direct"},"sex":{"value":"male"},"age":{"value":30,"unit":"years"},"height":{"value":66.9291339,"unit":"in"},"weight":{"value":154.323584,"unit":"lb"},"activity":{"value":"moderate"},"daily_deficit":{"value":500,"unit":"kcal"}}	{"resting_energy":1617.5,"target_calories":2007.1}
Invalid zero timeframe	{"scenario":{"value":"goal"},"sex":{"value":"male"},"age":{"value":30,"unit":"years"},"height":{"value":170,"unit":"cm"},"weight":{"value":70,"unit":"kg"},"activity":{"value":"moderate"},"target_weight":{"value":65,"unit":"kg"},"timeframe_weeks":{"value":0,"unit":"weeks"}}	Accessible validation error

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On this page

Direct answer

A calorie deficit exists when energy intake is lower than energy expenditure over time. If estimated maintenance is 2,500 kcal/day and intake is 2,000 kcal/day, the planned deficit is about 500 kcal/day.

calorie deficit = estimated expenditure − calorie intake

The reverse expression, intake − expenditure, is energy balance and becomes negative during a deficit. The interface and article must use one convention consistently.

For the next related calculation, use the Protein Calculator. Estimate an adult protein range.

Continue from this result with the Calorie Calculator. Apply an explicit percentage above or below maintenance.

Continue this planning task with the Weight Loss Timeline Calculator. Translate a selected energy gap into a labeled linear timeline.

How to use the calculator

Choose a direct daily deficit or a target-weight scenario.
Enter age, sex, height, current weight, and the activity description that represents a normal week.
For a direct scenario, enter the positive calorie amount to subtract from maintenance.
For a goal scenario, enter the target weight and timeframe in weeks.
Review the maintenance estimate, signed daily change, linear weekly equivalent, and limitations.

To compare this result with another relevant method, open the Body Fat Calculator. Track an estimated composition trend.

Formula and methodology

The calculator uses the verified Mifflin-St Jeor resting-energy equation:

male REE = 10W + 6.25H - 5A + 5

female REE = 10W + 6.25H - 5A - 161

where weight is kilograms, height is centimeters, and age is years. Estimated maintenance equals REE multiplied once by the selected activity factor.

Direct mode uses target intake = maintenance - selected deficit. Goal mode uses daily energy change = (target weight - current weight) x 7,700 / days, where days equals weeks multiplied by seven. Negative, zero, and positive changes are labeled as deficit, maintenance, and surplus.

The goal calculation is a linear starting estimate. For dynamic modeling, compare it with the NIDDK Body Weight Planner.

Worked example

Assume current weight 90 kg, target weight 80 kg, 140 days, and estimated maintenance 2,500 kcal/day.

planned deficit = (90 − 80) × 7,700 ÷ 140 = 550 kcal/day

estimated target intake = 2,500 − 550 = 1,950 kcal/day

The implied average is 0.5 kg/week. Actual scale change will not be perfectly linear because water, glycogen, gut contents, adherence, and expenditure change.

Precision and recalculation

Keep full internal precision for BMR, activity multiplication, days, and energy change; round only displayed calories and rates. Do not treat a target such as 1,947 kcal as biologically exact. Start with a practical rounded target, observe a multi-week trend, and use How to Recalculate Calories During Weight Loss before making a large adjustment.

How large should the deficit be?

There is no universal number. A smaller person, older adult, athlete, or person with a medical condition may need a different approach from a larger healthy adult. CDC notes that gradual, steady weight loss—about 1 to 2 lb per week—is more likely to be maintained, but this is context, not a promise or an individual prescription. Review How Big Should My Calorie Deficit Be?.

Who should not use this as a self-directed target

Do not use this calculator as stand-alone guidance for children or adolescents, pregnancy or breastfeeding, an eating disorder or history of one, underweight, frailty, significant kidney/liver/heart disease, diabetes medication adjustment, or any condition requiring prescribed nutrition. Consult an appropriate clinician or registered dietitian.

Limitations

BMR equations estimate group averages and can be wrong for an individual.
Activity factors are broad multipliers and often create the largest uncertainty.
The 7,700-kcal-per-kg rule is linear; bodies adapt as weight and intake change.
Short-term scale change includes water and glycogen, not only fat.
Food labels, portions, tracking, wearables, and exercise estimates contain error.
Weight change can be affected by medicines, sleep, stress, hormones, illness, and fluid balance.

Inputs, outputs and result meaning

Calculates estimated daily calorie target, estimated resting energy, estimated maintenance, and estimated daily calorie change from calculation scenario, sex used by the equation, age, and height with visible method, validation, precision, and limitations.

Inputs

Calculation scenario: Available choices are Choose a daily calorie deficit and Explore a target weight and timeframe.
Sex used by the equation: The published Mifflin-St Jeor equation uses sex-specific constants. Available choices are Male and Female.
Age: Supported units include years (yr). The supported range is 18 through 100.
Height: Supported units include centimeters (cm), meters (m), inches (in), feet (ft), and feet / inches (ft / in). The supported range is 1.2 through 2.3.
Current weight: Supported units include grams (g), kilograms (kg), and pounds (lb). The supported range is 30 through 300.
Typical activity level: Activity multipliers are broad estimates; day-to-day expenditure varies. Available choices are Sedentary, Lightly active, Moderately active, Very active, and Extra active.
Daily calorie deficit: Supported units include kilocalories (kcal). The supported range is 0 through 1,500.
Target weight: Supported units include grams (g), kilograms (kg), and pounds (lb). The supported range is 30 through 300.
Timeframe: Supported units include weeks (wk). The supported range is 1 through 260.

Outputs

Estimated daily calorie target: This is the primary result. It is displayed in kcal/day. The visible value is displayed without decimal places.
Estimated resting energy: It is displayed in kcal/day. The visible value is displayed without decimal places.
Estimated maintenance: It is displayed in kcal/day. The visible value is displayed without decimal places.
Estimated daily calorie change: It is displayed in kcal/day. The visible value is displayed without decimal places.
Estimated weekly calorie change: It is displayed in kcal/week. The visible value is displayed without decimal places.
Linear weekly weight-change equivalent: It is displayed in kg/week. The visible value uses up to 2 decimal places according to the output rule.
Selected weight change: It is displayed in kg. The visible value uses up to 1 decimal places according to the output rule. It appears only when the selected mode supports this result.

Target calories = estimated maintenance - selected daily deficit. Keep the result label, unit, selected mode, and stated limitations together when sharing the answer.

Frequently asked questions

Is a 500-calorie deficit right for everyone?

No. It represents a different percentage of maintenance for different people and may be inappropriate in some circumstances. Use the implied rate and professional context, not a universal subtraction.

Why did my weight not match the calculator?

Maintenance and activity are estimated, intake tracking has error, and short-term scale weight includes water. Compare a consistent multi-week trend before concluding that the estimate failed.

Should I subtract exercise calories again?

Not automatically. If the selected activity factor already represents normal exercise, adding full exercise calories again can double-count activity.

How often should I recalculate?

Recalculate after a meaningful weight or activity change, or when a well-measured trend differs from the plan for several weeks. Avoid daily target changes.

Sources

Evidence and editorial status

Evidence for this package was checked on September 10, 2026. This material is educational and is not medical diagnosis, treatment, or individualized nutrition advice.