How to calculate calorie deficit?

You are eating less, skipping snacks, and the scale still will not move. In most cases the problem is not willpower. It is that nobody showed you how to calculate calorie deficit properly, so the “deficit” you are aiming for is really a guess. This guide gives you the exact formula, five simple steps and two worked examples, so you finish with a daily calorie target built around your own body instead of a generic number.

What Is a Calorie Deficit?

A calorie deficit happens when you take in fewer calories than your body uses in a day. To cover the shortfall, your body draws on stored energy, mainly body fat, and over time that is what produces weight loss. This idea is called energy balance.

There are three possible states:

Calorie deficit: you eat less than you burn, so weight goes down.
Maintenance: you eat about what you burn, so weight stays steady.
Calorie surplus: you eat more than you burn, so weight goes up.

You can create a deficit by eating less, moving more, or combining both. Whichever route you choose, the first job is the same: work out how many calories you burn in a day.

The Calorie Deficit Formula

The formula is short:

Calorie deficit = TDEE − calories eaten

Daily calorie target = TDEE − the deficit you want

TDEE stands for Total Daily Energy Expenditure, the full number of calories you burn in 24 hours, including rest, digestion, daily movement and exercise. It is also called your maintenance calories. If you want the full background, read our complete TDEE guide.

How to Calculate Calorie Deficit in 5 Steps?

Follow these steps in order. If you would rather skip the maths, our free TDEE calculator does steps 1 and 2 for you in seconds.

BMR (Mifflin-St Jeor)
TDEE (BMR × activity)
Deficit (10 to 20 percent)
Target (TDEE − deficit)
Adjust(every 2 to 3 weeks)

Step 1: Estimate your BMR

Your basal metabolic rate (BMR) is the energy your body needs at complete rest. The Mifflin-St Jeor equation is a widely used way to estimate it:

Sex	BMR equation (kg, cm, years)
Men	(10 × weight) + (6.25 × height) − (5 × age) + 5
Women	(10 × weight) + (6.25 × height) − (5 × age) − 161

Need the numbers explained? See our BMR calculator.

Step 2: Multiply by your activity factor to get TDEE

Your BMR only covers rest. To include daily movement and exercise, multiply it by the factor that best matches a typical week:

Activity level	What it looks like	Multiplier
Sedentary	Desk job, little or no exercise	1.2
Lightly active	Light exercise 1 to 3 days a week	1.375
Moderately active	Moderate exercise 3 to 5 days a week	1.55
Very active	Hard exercise 6 to 7 days a week	1.725
Extremely active	Very hard training plus a physical job	1.9

TDEE = BMR × activity multiplier. Most people overestimate how active they are, so if you sit between two levels, choose the lower one.

Step 3: Choose the size of your deficit

For most adults, a deficit of 10 to 20 percent of TDEE is a sensible range. It is large enough to produce steady progress and small enough to keep your energy, mood and training intact. We cover this choice in detail below.

Step 4: Subtract the deficit to set your daily target

10 percent deficit: TDEE × 0.90
15 percent deficit: TDEE × 0.85
20 percent deficit: TDEE × 0.80

The result is your daily calorie target. Then check it against a safety floor. Many health guidelines advise against eating below roughly 1,200 calories a day for women or 1,500 for men without medical supervision. If your target falls under that, choose a smaller deficit.

Step 5: Track for 2 to 3 weeks, then adjust

Every formula is an estimate. Eat at your target for two to three weeks, weigh yourself at the same time each morning, and compare the weekly average with the previous week. If your weight is not moving the way you want, change your intake by 100 to 150 calories and test again. Recalculate your TDEE whenever you lose or gain a meaningful amount of weight.

Two Worked Examples

The following examples apply the Mifflin-St Jeor equation and the activity multipliers from Steps 1 to 4. Use them as a template for your own numbers.

Example 1: Woman, 32 years, 70 kg, 165 cm, lightly active

BMR: (10 × 70) + (6.25 × 165) − (5 × 32) − 161 = 1,410 calories
TDEE: 1,410 × 1.375 = 1,939 calories
Chosen deficit: 15 percent, so 1,939 × 0.85 = 1,648 calories per day

This gives a calorie deficit of about 291 calories daily. The target sits above the 1,200-calorie safety floor, so no adjustment is needed.

Example 2: Man, 40 years, 90 kg, 178 cm, sedentary

BMR: (10 × 90) + (6.25 × 178) − (5 × 40) + 5 = 1,818 calories
TDEE: 1,818 × 1.2 = 2,181 calories
Chosen deficit: 20 percent, so 2,181 × 0.80 = 1,745 calories per day

This creates a calorie deficit of roughly 436 calories daily, which is comfortably above the 1,500-calorie floor for men.
Both results are estimates. Treat them as a starting point and refine them using the tracking method in Step 5.

How Fast Will You Lose Weight?

One kilogram of body fat holds roughly 7,700 calories. This figure is an approximation, but it helps you set realistic expectations.

Example 1: 291 calories × 7 days = 2,037 calories per week, or about 0.25 kg per week.
Example 2: 436 calories × 7 days = 3,052 calories per week, or about 0.4 kg per week.

A steady pace of 0.25 to 0.75 kg per week is considered sustainable for most adults. Early weight changes may look faster because of water loss, and later progress often slows as your body weight drops. This is normal, and it is the reason Step 5 asks you to recalculate your TDEE after meaningful weight change.

Common Mistakes When Calculating a Calorie Deficit

Overestimating activity level. Choosing “very active” for a desk job inflates your TDEE and erases the deficit.
Cutting calories too low. Extreme restriction is difficult to maintain and often ends in rebound eating.
Ignoring liquid calories. Juices, sweetened coffee and soft drinks add up quickly.
Judging results too early. Daily weight changes are noisy. Use the weekly average instead.
Never recalculating. Your maintenance calories fall as your weight falls, so your target needs periodic updates.
Neglecting protein and strength training. Adequate protein and resistance exercise help preserve muscle while you lose fat.

Who Should Be Careful With a Calorie Deficit?

Calorie restriction is not appropriate for everyone. Consult a qualified healthcare professional before starting if you are pregnant or breastfeeding, under 18, living with diabetes or another medical condition, taking regular medication, or have a history of disordered eating. This article is for general information only and is not a substitute for medical advice.

Use this formula: Calorie deficit = TDEE − calories eaten. First estimate your BMR with the Mifflin-St Jeor equation, then multiply it by your activity factor to get your TDEE. Subtract your daily food intake from that number. Our free TDEE calculator completes the first two steps automatically.

For most adults, a reduction of 10 to 20 percent of TDEE is a sensible range. For example, if your TDEE is 2,000 calories, a 15 percent deficit gives a daily target of 1,700 calories. This range supports steady fat loss without extreme hunger or loss of energy.

Most people notice changes on the scale within two to three weeks, although early drops often include water weight. Visible changes in body shape usually take four to eight weeks of consistency. Tracking the weekly average of your weight gives a more reliable picture than daily readings.

Yes. Portion control, regular meals, higher protein and fibre intake, fewer liquid calories and more daily movement can all create a calorie deficit without strict tracking. However, counting calories for a few weeks is a useful way to learn portion sizes and check whether your estimate is accurate.

There are several common reasons:

Your activity level was overestimated, so your TDEE is too high.
Food portions or drinks are being under-logged.
Your weight has dropped, so your maintenance calories have fallen.
Water retention is hiding fat loss in the short term.

Recalculate your TDEE, track accurately for two to three weeks, and adjust your intake by 100 to 150 calories if needed.

Conclusion

To calculate your calorie deficit, estimate your BMR, multiply it by your activity factor to find your TDEE, and subtract a moderate 10 to 20 percent. Then track your weekly average for two to three weeks and adjust by 100 to 150 calories when needed. A realistic, steady calorie deficit is far more effective than a drastic one, because it is the version you can actually maintain.
Ready to start? Use our TDEE calculator to get your personalised daily calorie target in seconds, or read our complete TDEE guide and BMR calculator page for the full background.

How to calculate calorie deficit?

What Is a Calorie Deficit?