To lose weight, you need to eat fewer calories than your body burns each day - and for most people, a comfortable target is about 250 to 500 calories below their daily maintenance level. That usually adds up to a steady, sustainable loss of roughly 0.25 to 0.5 kg (about 0.5 to 1 lb) per week.
The exact number is personal, because it depends on your age, sex, height, weight, and how active you are. Use the calculator below to get your estimate, then read on to understand what the numbers mean and how to make them work in real life.
Weight loss starts with energy balance
Your body is always trading energy. You take energy in from food and drink, and you spend it through three main channels: keeping you alive at rest, digesting what you eat, and moving around. The relationship between energy in and energy out is called energy balance, and it is the foundation of every evidence-based approach to weight management.
When you take in roughly the same energy you burn, your weight holds steady. Take in less, and your body makes up the difference by drawing on stored energy - including body fat - so you lose weight. Take in more, and the surplus is stored. This is why the Dietary Guidelines for Americans, 2020-2025 frame healthy weight as a question of matching your calorie intake to your needs.
It is worth being clear about what this does and does not mean. Energy balance is the lever that moves the scale, but the foods you choose still matter enormously for how you feel, how full you stay, and your long-term health. A 300-calorie snack of nuts and a 300-calorie soda affect your hunger and nutrition very differently, even though they cost the same against your daily budget. Counting calories and eating well are partners, not rivals.
“Calories” can sound clinical, but the idea is simple: they are just a unit of energy. Counting them is how you turn the abstract principle of energy balance into something you can see and steer. If you want the deeper science of how that gap drives fat loss, we cover it in What Is a Calorie Deficit?. For now, the takeaway is that a moderate, consistent deficit is the engine of weight loss.
How your calorie needs are estimated
To know how much to eat to lose weight, you first need a reasonable estimate of how much you burn. That number has two parts.
Step 1: Your BMR (the calories you burn at rest)
Your basal metabolic rate (BMR) is the energy your body uses just to keep you alive - breathing, circulating blood, repairing cells - if you did nothing but rest all day. It is the single biggest piece of most people’s daily burn.
The most widely validated way to estimate BMR is the Mifflin-St Jeor equation, published in 1990 after researchers measured resting energy in nearly 500 healthy adults (Mifflin et al., 1990). It is the formula the calculator above uses, and research comparing prediction equations has found it tends to land closer to measured values than older alternatives. The equation looks like this:
- Women: BMR = (10 x weight in kg) + (6.25 x height in cm) - (5 x age) - 161
- Men: BMR = (10 x weight in kg) + (6.25 x height in cm) - (5 x age) + 5
Step 2: Your TDEE (resting burn plus daily activity)
Of course, you do not lie still all day. To estimate your total daily energy expenditure (TDEE) - the full amount you burn - you multiply your BMR by an activity factor that reflects how much you move:
| Activity level | What it looks like | Multiplier |
|---|---|---|
| Sedentary | Little or no exercise, desk job | 1.2 |
| Lightly active | Light exercise 1 to 3 days a week | 1.375 |
| Moderately active | Exercise 3 to 5 days a week | 1.55 |
| Very active | Hard exercise 6 to 7 days a week | 1.725 |
| Extra active | Hard daily exercise plus a physical job | 1.9 |
So if your BMR is 1,400 calories and you are lightly active, your estimated TDEE is about 1,400 x 1.375, or roughly 1,925 calories a day. That TDEE is your maintenance level: eat that amount and your weight should stay about the same.
One honest caveat: these are estimates, not lab measurements. Real-world burn varies between people, and activity multipliers are approximations. Treat your number as a smart starting point and let the scale tell you whether to fine-tune it.
What a safe calorie deficit looks like
Once you know your maintenance calories, creating a deficit is straightforward: eat a bit less than that number. The question is how much less.
A practical, research-backed range is about 250 to 500 calories per day below maintenance. That pace generally produces a loss of around 0.25 to 0.5 kg (about 0.5 to 1 lb) per week. The CDC notes that people who lose weight at a gradual, steady pace - about 1 to 2 pounds a week - are more likely to keep it off than people who lose it faster (CDC).
The calculator above turns this into two concrete targets:
- A mild deficit of 250 calories below your TDEE, for slower, very comfortable loss.
- A moderate deficit of 500 calories below your TDEE, for a slightly faster pace.
Both keep you in the gradual zone that tends to stick. There is no medal for picking the bigger deficit - the best one is the one you can actually live with week after week. If a 250-calorie cut feels easy and your weight is trending down, there is no need to push harder.
You will also notice the calculator never recommends going below roughly 1,200 calories for women or 1,500 calories for men. Those are sensible floors: eat much less than that without medical guidance and it becomes genuinely difficult to get enough protein, vitamins, and minerals.
Why crash diets backfire
It is tempting to slash calories hard and chase fast results. In practice, very aggressive dieting tends to work against you.
Very-low-calorie diets - typically defined as providing only about 800 calories a day - are designed for short-term use in specific medical situations and under a doctor’s supervision, not as a do-it-yourself plan (NIH National Task Force, 1993). Outside that setting, eating too little brings predictable problems:
- Muscle loss. When the deficit is severe, more of the weight you lose can come from lean muscle rather than fat. Because muscle helps set your resting burn, losing it makes maintenance harder later.
- A shrinking burn. Your metabolism naturally adjusts downward as you lose weight, because a lighter body needs fewer calories. The NIDDK notes that your body needs fewer calories at your new, lower weight, which is part of why keeping weight off takes ongoing effort (NIDDK).
- Rebound and burnout. Extreme restriction is hard to sustain. Intense hunger, fatigue, and a sense of deprivation often lead to giving up - and to regaining what was lost.
A moderate deficit sidesteps most of this. You lose fat at a livable pace, hold on to more muscle, and build habits you can keep.
Protein and feeling full
Cutting calories is easier when you are not constantly hungry, and this is where protein earns its reputation. Of the three macronutrients, protein is the most satisfying per calorie, and it helps protect muscle while you are in a deficit.
A review of the research on protein and body weight concluded that higher-protein eating patterns support appetite control and weight management, with the benefit linked to getting enough protein spread across the day rather than crammed into one meal (Leidy et al., 2015). In plain terms, building meals around a solid protein source - eggs, Greek yogurt, chicken, fish, tofu, beans, or lentils - tends to keep you full longer on the same calorie budget.
That same review pointed to meal-sized portions of roughly 25 to 30 grams of protein as a useful practical target - about the amount in a chicken breast, a couple of eggs with a serving of yogurt, or a generous scoop of beans or lentils. You do not need to hit a precise gram count, but aiming for a real protein source at each meal is a simple rule that does a lot of the heavy lifting.
You also do not need a complicated macro spreadsheet to benefit. Simply anchoring each meal with protein, and filling the rest of the plate with vegetables, fruit, whole grains, and healthy fats, makes a calorie target feel far less like a diet. For more on balancing protein with the rest of your day, the broader Calorie Counting hub walks through the essentials.
Adjust your target as you lose weight
Here is a detail that trips up a lot of people: the calorie target that works today will not work forever. As you get lighter, you burn fewer calories, so the deficit you started with quietly shrinks. This is normal, and it is the main reason weight loss tends to slow over time rather than continue in a straight line.
The fix is simple - recalculate. A reasonable habit is to update your numbers every time you lose about 4 to 6 kg (roughly 10 lb), or whenever your progress clearly stalls for two to three weeks despite consistent effort. Plug your new weight back into the calculator and adjust your target down if needed.
A few practical notes on tracking progress:
- Weigh yourself consistently, ideally at the same time of day, and watch the weekly trend rather than daily ups and downs. Day-to-day shifts are mostly water and food in transit, not fat.
- Expect plateaus. A pause of a week or two is part of the process, not a failure.
- Give changes time. After adjusting your calories, wait two to three weeks before judging whether the new target is working.
The real secret: consistent tracking
If there is one habit that separates people who reach their goal from those who stall, it is paying attention to what they eat. The NIDDK highlights that tracking your progress helps you spot your strengths, find areas to improve, and stay on course (NIDDK). Awareness alone often nudges your choices in a better direction.
The good news is that tracking no longer means a tedious paper food diary. Apps that estimate calories from a photo of your plate, scan barcodes, or let you log a meal in seconds remove most of the friction - which matters, because the method you will actually keep using beats the “perfect” method you abandon. This is exactly the gap CalcEat is built to close: snap a picture of your meal and get an instant calorie and macro estimate, no manual entry required.
And you do not have to weigh every gram to make this work. Reasonable portion estimates, logged consistently, are enough to keep you moving in the right direction - something we break down in How to Count Calories Accurately Without Weighing Every Meal.
Putting it all together
Losing weight comes down to a handful of durable ideas: eat a little less than you burn, keep the deficit moderate, lean on protein to stay full, recalculate as you shrink, and track consistently enough to learn from the feedback.
Start by running your numbers in the calculator above, pick the deficit that feels genuinely doable, and give it a few weeks. Steady beats drastic almost every time - and small changes you can sustain will carry you much further than any crash diet ever could. You have got this.
This article is general information, not medical advice. If you have a health condition, are pregnant or breastfeeding, or are considering a large change to how you eat, talk with your doctor or a registered dietitian first.
