Below is a simple but highly accurate scientific calorie calculator, along with five evidence-based tips on how to sustainably reduce your calorie intake.
Enter your details in the calculator below to figure out how many calories you should be eating per day to either maintain or lose weight.
The answer to this question depends on numerous factors, including your age, height, current weight, activity level, and metabolic health, among several others.
When trying to lose weight, a general rule of thumb is to reduce your calorie intake to 500 fewer calories than your body needs to maintain your current weight. This will help you lose about 1 pound (0.45 kg) of body weight per week.
Below are average calorie ranges that consider these factors.
The average, moderately active woman between the ages of 26–50 needs to eat about 2,000 calories per day to maintain her weight and 1,500 calories per day to lose 1 pound (0.45 kg) of weight per week.
Women who are active and walk more than 3 miles per day will need to consume 2,200 calories or more daily to maintain their weight and at least 1,700 calories to lose 1 pound (0.45 kg) of weight per week.
Young women in their early 20s have higher calorie needs. They require about 2,200 calories per day to maintain their weight.
Women over age 50 generally require fewer calories. The average moderately active woman over 50 needs about 1,800 calories per day to maintain her weight and 1,300 calories per day to lose 1 pound (0.45 kg) per week.
These estimates do not apply to women who are pregnant or breastfeeding, as they have significantly higher calorie needs.
The average, moderately active man between the ages of 26–45 needs 2,600 calories per day to maintain his weight and 2,100 calories per day to lose 1 (0.45 kg) pound per week.
Active men who walk more than 3 miles per day may require 2,800–3,000 calories per day to maintain their weight and 2,300–2,500 calories per day to lose 1 pound (0.45 kg) of weight per week.
Young men ages 19–25 have higher energy needs. They require an average of 2,800 calories per day to maintain their weight and up to 3,000 if they’re active. To lose 1 pound (0.45 kg) per week, moderately active young men should consume 2,300–2,500 calories daily.
Energy needs decrease as men age. Between the ages of 46–65, moderately active men need an average of 2,400 calories per day. After 66 years, the average man’s calorie needs decrease to about 2,200 calories per day.
Children have widely varying calorie needs based on their age, size, and activity level.
Whereas the average toddler requires 1,200–1,400 calories per day, the average moderately active teenager requires 2,000–2,800 calories per day. Active teenage boys require even more.
Children who are growing and developing normally and engage in regular physical activity usually don’t need to count calories. When they’re provided with a range of healthy options to eat, most moderately active kids naturally eat the amount of food their body requires.
A calorie is a unit that measures energy. Calories are usually used to measure the energy content of foods and beverages. To lose weight, you need to eat fewer calories than your body burns each day.
Calories are simply a measure of energy. To gain weight, you need to consume more calories than you expend. Conversely, you lose weight if you use more calories than you consume.
That said, cutting calories without considering which foods you eat is usually not a sustainable way to lose weight. For example, choosing more nutrient-dense foods will benefit your health more than opting for nutrient-poor ones.
Though it works for some people, most end up hungry and eventually revert to their old habits.
For this reason, it’s highly recommended to make a few other permanent changes to help you maintain a calorie deficit in the long term, without feeling starved.
The following evidence-based eating and lifestyle changes have been shown to help people lose weight.
1. Eat more protein
When it comes to losing weight, protein is the king of nutrients.
Adding protein to your diet is a simple, effective way to lose weight with minimal effort.
Studies show that protein both increases your metabolic rate and helps curb your appetite .
Because protein requires energy to metabolize, a high protein diet can increase the number of calories you burn by 80–100 calories per day.
Eating protein helps you stay fuller longer and may help you consume fewer calories throughout the day. One older study showed that people who ate 30% of calories from protein ate 441 fewer calories per day.
In other words, you can increase the number of calories you burn and decrease the number of calories you consume simply by adding protein to your diet. Protein can also help fight cravings.
In one 2011 study, consuming 25% of daily calories from protein reduced obsessive thoughts about food by 60%, as well as the desire to snack late at night by 50%.
If you want to lose weight sustainably and with minimal effort, consider increasing your protein intake.
It may not only help you lose weight but also prevent or reduce weight regain.
2. Avoid sugary soft drinks and fruit juices
Another relatively easy change you can make is to eliminate liquid sugar calories from your diet.
This includes sodas, fruit juices, chocolate milk, and other beverages with added sugar.
Your brain doesn’t register liquid calories in the same way it registers solid calories.
For this reason, drinking sugary soda doesn’t make your brain automatically compensate by having you eat smaller amounts of other things instead.
Studies have shown that sugary drinks are strongly linked to an increased risk of obesity, with one study in children showing a 60% increased risk for each daily serving of a sugar-sweetened beverage.
The harmful effects of sugar go beyond weight gain. It can have negative effects on metabolic health and raise your risk of many diseases.
Eating fruit, which also contains fiber and other important nutrients, isn’t associated with the same negative effects as drinking fruit juice or other sweetened beverages. However, eating large amounts of added sugar and sugary drinks can harm your health in a variety of ways.
There’s no physiological need for these beverages, and the long-term benefits of avoiding them can be enormous.
3. Drink more water
One very simple trick to increase weight loss is to drink more water.
Studies have suggested drinking water can increase the number of calories you burn for up to 90 minutes.
Drinking about eight, 8-ounce glasses (2 liters) of water per day may make you burn about 96 more calories.
However, recent studies suggest drinking water may not increase the number of calories you burn.
The timing of when you drink water may be even more important. Drinking water immediately before meals may help reduce hunger and make you eat fewer calories.
In one 12-week study, drinking 17 ounces (0.5 liters) of water half an hour before meals made people lose 44% more weight.
When combined with a healthy diet, drinking more water, especially before meals, appears to be helpful if you need to lose weight.
Drinking caffeinated beverages, such as coffee and green tea, may also boost metabolism slightly, at least in the short term. Doing so is associated with losing weight and keeping it off .
4. Exercise and lift weights
When you eat fewer calories, your body compensates by saving energy, making you burn fewer calories.
This is why long-term calorie restriction can significantly reduce your metabolism.
Plus, it can lead to a loss of muscle mass. Muscle is metabolically active, so this can reduce your metabolism even further.
The only proven strategy to prevent this effect is to exert your muscles by lifting weights.
This has been repeatedly shown to prevent muscle loss and stop your metabolism from slowing during long-term calorie restriction.
When trying to lose weight, it’s important to maintain or strengthen your muscles in addition to losing fat.
If you can’t get to a gym, consider doing bodyweight exercises, such as pushups, squats, and situps, at home.
Doing some cardio, including walking, swimming, or jogging, can also be important — not necessarily for weight loss but for optimal health and general well-being.
What’s more, exercise has a variety of other benefits that go beyond weight loss, such as increased longevity and energy levels, a lower risk of disease, and simply feeling better every day.
5. Reduce your refined carb intake
Cutting carbs is a very effective way to lose weight, as it reduces appetite and makes you eat fewer calories.
Studies have shown that eating a low carb diet until fullness can make you lose about two to three times more weight than a calorie-restricted, low fat diet.
What’s more, low carb diets have many other benefits for health, especially for people with type 2 diabetes or metabolic syndrome.
Yet, you don’t have to go low carb. Simply ensure that you eat quality, fiber-rich carb sources, focusing on whole, single-ingredient foods.
If you stick to whole foods, the exact composition of your diet becomes less important.
Many websites and apps can help you track your calorie intake.
Try using a calorie counter for at least a few days to see how many calories, carbs, protein, fat, fiber, vitamins, and minerals you’re actually eating.
Seeing the numbers like this can often be eye-opening.
How many calories you need per day depends on whether you want to maintain, lose, or gain weight, as well as various other factors, such as your gender, age, height, current weight, activity level, and metabolic health.