Fat Loss Calculator: Calculate Your TDEE, Deficit & Macros
Calculate your TDEE, fat-loss calories and daily protein, carbs and fats. Adjust your calorie deficit and macro split to fit how you prefer to eat.
Use this free fat loss calculator to estimate your TDEE, daily calorie target and macros for fat loss. Enter your age, sex, height, weight and activity level, then adjust your calorie deficit and carb-to-fat preference to create a starting plan.
Your calories, TDEE and macros — in under 60 seconds.
Estimate maintenance calories, choose a sensible fat-loss deficit, and adjust your carb-to-fat preference without changing your protein target.
Your starting numbers
Use these as an evidence-informed estimate, then calibrate against your real-world trend.
The part most calculators miss: calibrate it.
Run these numbers consistently for about 2 weeks, compare your average weight trend, and make a small adjustment only if the trend and your adherence show the estimate is off. A calculator is a starting point, not a metabolic measurement.
Want the system behind the numbers?
Choose your path to see the next step for getting leaner without turning your diet into a tiny-food misery contest.
Important: This calculator is educational and is not medical advice. It is intended for adults 18+. Do not use it as a substitute for individualized care during pregnancy or breastfeeding, eating-disorder treatment/recovery, or when a medical condition or medication affects nutrition, body weight, or metabolism.
How the calculator works + research sources
- Mifflin–St Jeor: used when body-fat percentage is not entered. PubMed: A new predictive equation for resting energy expenditure.
- Müller equation: used when body-fat percentage is entered, allowing fat-free mass and fat mass to inform the resting-energy estimate. PubMed: World Health Organization equations have shortcomings….
- Protein: the default target is set at up to 1.6 g/kg/day, consistent with evidence showing diminishing additional resistance-training benefit above roughly 1.6 g/kg/day for many healthy adults. PubMed: Morton et al. meta-analysis.
- Weight change is dynamic: simple calorie rules do not perfectly predict long-term weight loss because energy expenditure adapts. See the NIH/NIDDK Body Weight Planner.
What is a fat loss calculator?
A fat loss calculator estimates how many calories your body burns each day, how many calories to eat to lose fat, and how to split those calories between protein, carbs and fats.
Instead of guessing how little you should eat, it starts with your estimated Total Daily Energy Expenditure (TDEE), then creates a calorie deficit based on your goal.
Think of the result as a smart starting point—not a permanent prescription. Your real-world progress over the next couple of weeks tells us whether that starting point needs to move up or down.
How many calories should I eat to lose fat?
Start by eating fewer calories than your estimated TDEE—but not necessarily as few as possible.
Your TDEE is an estimate of how many calories you burn across an average day, including the energy your body uses at rest plus your normal activity.
If your maintenance level is approximately 2,500 calories, for example, a 20% deficit would give you a starting fat-loss target of about 2,000 calories per day.
That 500-calorie gap is the deficit.
But bigger isn’t automatically better.
An aggressive deficit may produce faster scale changes initially, but slower rates of weight loss can be more favorable for preserving lean mass, particularly as someone becomes leaner.
That’s why this calculator doesn’t just give you one arbitrary calorie number. You can adjust the deficit and see exactly how your calorie and macro targets change.
Start with a target you can realistically follow. Then let your results—not your impatience—tell you what to change.
How this calculator calculates your TDEE
Your TDEE isn’t measured directly by this calculator. It’s estimated in two steps.
First, the calculator estimates how much energy your body uses at rest.
By default, it uses the Mifflin–St Jeor equation, which estimates resting energy expenditure from your weight, height, age and sex. The equation was developed from measurements of resting energy expenditure in adults and remains one of the most widely used predictive equations.
If you provide body-fat information, the calculator can instead use the Müller equation, which incorporates fat-free mass and fat mass alongside age and sex. Research behind the Müller equations found that both fat-free mass and fat mass independently contributed to resting energy expenditure.
Your estimated resting expenditure is then adjusted for your activity level to produce your estimated Total Daily Energy Expenditure, or TDEE.
In plain English:
Resting needs + your activity = estimated maintenance calories.
Then we create your chosen deficit from that number.
No equation can know exactly how much you move, fidget, train, eat or recover every day—which is why the next step matters even more: calibrating the estimate against your actual results.
What calorie deficit should I use?
For most people, the best deficit is the smallest one that produces meaningful, sustainable progress.
A practical place to begin is often around 15–20% below your estimated TDEE, rather than immediately choosing the most aggressive option available.
The calculator lets you move the deficit slider so you can see the tradeoff in real time:
Smaller deficit → more calories, easier adherence, potentially slower progress.
Larger deficit → fewer calories, potentially faster progress, but less room for food and recovery.
Research in resistance-trained populations suggests that more gradual weight loss can be advantageous for preserving lean mass, especially in leaner individuals.
So don’t automatically drag the slider to the maximum.
If you train regularly, are already relatively lean, struggle with hunger or want to protect performance, starting toward the gentler end may make more sense.
Your objective isn’t to win the first seven days of dieting.
It’s to choose a deficit you can sustain long enough to actually get leaner.
How much protein should I eat while losing fat?
Around 1.6 grams of protein per kilogram of body weight per day is a useful starting point for many active adults.
That’s approximately 0.73 grams per pound.
Protein matters during fat loss because the goal isn’t simply to make the number on the scale smaller. Ideally, you want to lose fat while retaining as much lean tissue as possible—particularly if you’re also resistance training.
A large meta-analysis found that, during resistance training under non-energy-restricted conditions, benefits for fat-free-mass gains tended to level off around 1.6 g/kg/day. Sports-nutrition guidance commonly places protein intake for exercising adults in roughly the 1.4–2.0 g/kg/day range.
But 1.6 g/kg is a starting point, not a magic number.
Your ideal intake can vary with your body composition, training, calorie deficit, food preferences and individual circumstances. Lean resistance-trained athletes under calorie restriction, for example, may benefit from higher protein intakes than the general exercising population.
That’s why the calculator handles protein first, then lets you personalize what happens with the remaining calories.
Should I eat more carbs or more fat?
You don’t need to join Team Carbs or Team Fat to lose body fat.
Once you’re consistently consuming an appropriate number of calories and enough protein, there is considerable flexibility in how you divide the rest between carbohydrates and fats. Multiple dietary approaches—from lower-fat to lower-carbohydrate diets—can produce fat loss when they successfully create an energy deficit.
So the better question is:
Which split helps you eat well, train well and stick to your calories?
Prefer rice, potatoes, fruit and higher-carb meals? Slide the calculator toward carbs.
Prefer avocado, nuts, olive oil and fattier foods? Move it toward fats.
Train hard and feel better with more carbohydrate? Account for that.
Feel more satisfied with a little more dietary fat? Account for that too.
Your macros should serve the diet—not make the diet harder to follow.
That’s why this calculator keeps your protein target anchored while allowing you to adjust the carb-to-fat ratio based on your preference.
The plan you can consistently follow usually beats the theoretically “perfect” macro split you quit after nine days.
How accurate is a TDEE calculator?
A TDEE calculator is an estimate—not a metabolic test.
Equations can make an educated prediction from variables such as your weight, height, age, sex, body composition and reported activity. But they cannot perfectly know your actual daily movement, training output, food intake or individual energy expenditure.
Even sophisticated models of body-weight change account for the fact that energy expenditure and body composition change dynamically rather than following a perfectly fixed calories-in/calories-out formula.
So instead of asking:
“Is my TDEE number perfectly accurate?”
Ask:
“Is it accurate enough to give me a useful starting point?”
Then calibrate it.
The 14-Day Calibration Method
Use your calculator result consistently for approximately two weeks.
Track your body weight under reasonably similar conditions and focus on the trend, rather than reacting to a single weigh-in. Comparing averages is more useful than comparing one unusually high or low morning.
After 14 days:
If you’re progressing at a reasonable rate: keep your calories where they are.
If the trend isn’t moving: your real maintenance needs may be lower than the calculator estimated—or your actual intake/activity may differ from what was assumed.
If you’re losing faster than intended and hunger, recovery or training quality is suffering: consider easing the deficit.
The calculator gives you Version 1 of your plan.
Your own data makes Version 2 better.
Why isn’t my calculated TDEE matching my weight loss?
Because your calculated TDEE is a prediction, while your body is the real-world test.
A calculator can estimate your expenditure. It cannot see every variable affecting what happens afterward.
Your actual results can differ because:
- Your activity level was over- or underestimated.
- Your daily movement changed after starting the diet.
- Your calorie intake is different from what you estimate.
- Your exercise varies from week to week.
- Your body weight is being temporarily affected by water, food volume and other short-term fluctuations.
- Your energy expenditure can change as your body weight and calorie intake change over time.
Human body-weight change is dynamic; energy requirements do not remain perfectly fixed throughout weight loss. That’s one reason NIH’s Body Weight Planner uses dynamic modeling rather than assuming that one fixed calorie equation predicts progress indefinitely.
So if your calculator says your TDEE is 2,500 calories, don’t treat 2,500 like a laboratory result.
Treat it like a hypothesis.
Follow the plan.
Watch the trend.
Then adjust based on evidence.
The calculator gets you close. Your results make it personal.
Frequently Asked Questions
Is TDEE the same as BMR?
No.
Your BMR or resting energy expenditure represents the energy your body needs while at rest.
Your TDEE attempts to account for the rest of your day as well—movement, exercise and general activity.
That’s why your TDEE should normally be higher than your resting calorie estimate.
For fat-loss planning, TDEE is the more useful number because it gives you an estimate of the calories required to maintain your current weight before creating a deficit.
Should I eat back the calories I burn during exercise?
Usually, you should be careful about automatically adding every estimated exercise calorie back to your diet.
If you’ve already selected an activity level that includes your regular training, some of that activity is already reflected in your TDEE estimate. Adding the full amount again could effectively count the same activity twice.
Instead, use the calculator as your initial target and judge it against your 14-day trend.
If your training volume changes dramatically, recalculate or adjust from there.
Do I need to know my body-fat percentage?
No.
You can calculate an estimated TDEE using your weight, height, age, sex and activity level with the Mifflin–St Jeor equation.
Body-fat percentage is optional.
If you have a reasonably reliable estimate, it allows the calculator to use a body-composition-based equation that considers fat-free mass and fat mass.
If you don’t know it, don’t guess just to complete another field.
A good estimate with accurate inputs is more useful than a “more advanced” equation fed bad data.
How often should I recalculate my calories?
You don’t need to recalculate every time the scale moves.
Your calorie needs can change as your body weight, activity and lifestyle change, but reacting to every small fluctuation makes the process unnecessarily complicated.
Instead, stick with one target long enough to establish a meaningful trend.
If you’ve lost a significant amount of weight, your activity changes substantially, or progress has genuinely stalled for several weeks, that’s a sensible time to calculate again and compare the new estimate with your real-world data.
Why did my weight go up even though I ate in a calorie deficit?
Because scale weight and body fat are not the same thing.
Your body weight can move from day to day without representing an equivalent change in body fat. What matters for evaluating your calorie target is the trend over time, not whether tomorrow morning’s number is higher than today’s.
That’s why this calculator is designed around a 14-day calibration period instead of encouraging you to change your calories after one disappointing weigh-in.
Don’t let one data point rewrite the whole plan.
Can I lose fat without counting calories?
Yes. You don’t have to count every calorie to create an energy deficit.
Calorie tracking is simply one way of controlling energy intake.
Someone may also reduce their intake by changing portions, eating more filling foods, altering meal structure or following a consistent nutrition framework.
The calculator can still be useful because it shows you the approximate energy and protein targets behind the process—even if you ultimately choose to reach them without logging every meal.
Should men and women use different fat-loss calculators?
The underlying principle is the same: fat loss requires an energy deficit over time.
However, predictive equations can include sex because average resting-energy requirements differ after accounting for variables such as weight, height and age. The Mifflin–St Jeor equation, for example, uses different constants for males and females.
That’s why this calculator asks for sex when estimating your calorie needs.
From there, the fundamentals remain remarkably similar:
Find your starting calories.
Eat enough protein.
Train intelligently.
Track the trend.
Adjust when the evidence tells you to.
What should I do after I calculate my calories and macros?
Don’t turn your numbers into another diet you hate.
The calculator tells you approximately how much to eat.
The next step is learning how to build your diet so those numbers feel surprisingly easy to follow.
That means choosing foods, meals and training strategies that let you stay satisfied, protect muscle and make fat loss fit your actual life.
Your numbers are the target.
Your system is what determines whether you can keep hitting it.