The cornerstone of any good fitness plan is getting your diet right, and to do that, the first thing you need to do is to determine what your daily calorie needs are.
There are a lot of different online calculators you can use to find out how many calories you should eat per day. Some of them are ok, but most calorie calculators oversimplify by only using your age, weight, and gender (and perhaps BMI).
If you are a fitness nerd like me, you will probably want to know the correct scientific way of calculating what your daily calorie needs are.
It’s a very easy 5-step process. I have used my own data in the example below to show you how I work out what my daily calorie needs are.
Table of Contents
How to calculate your daily calorie needs
You can calculate your daily “maintenance calories” by following these easy steps:
Step 1: Find your current body weight in kilograms (if you live in the US, just divide your current weight in pounds by 2.2 to get your weight in kilograms).
Step 2: Multiply your weight in kilograms by 0.9 if you are a woman or 1.0 if you are a man.
Step 3: Multiply by 24
Step 4: Multiply by your “Lean Factor” from the table below (read on to learn how to find your body fat percentage if you don’t know it)
Example using my stats: 61 kg (134.5 lbs.) x 0.9 (female) x 24 x 0.95 (20% body fat) = 1252
This number is called your Basal Metabolic Rate (BMR). It’s how many calories you would burn in a day if you just lay on the couch all day and did nothing.
To find out how many calories you actually burn in a day, you need to multiply with your “Activity Modifier” from the table below.
Step 5: Multiply by Activity Modifier
My daily calorie need would be: 1252 (my BMR) x 1.55 (Light Activity) = 1940 calories/day
Important: No matter what this formula says, never eat less than 1,200 calories per day on average without consulting your medical team first. A very low daily calorie intake can lead to a slower metabolism, hormonal problems, and a number of other medical issues.
How to find your body fat percentage
As you can see, calculating your daily calorie needs is actually pretty simple, as long as you know your body fat percentage. Most gyms should be able to measure that for you, or a trainer can give you a very good estimate just by looking.
You can also use a tape measure and this online calculator to estimate your body fat percentage. It’s not as accurate, but you really only need an approximate number, so it should be good enough.
If you want a more accurate number (and to track any changes), you can invest in a scale that measures body fat percentage (you can buy the one I use HERE). It’s only $27.99 so it’s a worthwhile investment if you want to track your weight and body fat percentage.
How to decide your activity factor
The main mistake people make when using this calculation is to overestimate their physical activity level.
Even though I live a very active lifestyle and work out almost every day, I still only use the “Light Activity” multiplier. And that may even be on the high side because I also spend a lot (too much) time in front of a computer.
The higher multipliers are for people who use their bodies almost constantly throughout the day and therefore need a lot of energy, like construction workers, pro athletes, etc.
If you are pretty fit and active, you should probably use the “Light” or “Very Light” multiplier. If you are just starting a fitness program, use the “Very Light” multiplier.
Now that you know how many calories you burn in a day, the next step is to decide if you want to lose or gain weight.
How many calories should you eat to lose weight?
If you are trying to lose weight, I recommend eating around 400-500 calories less than you burn daily. That calorie deficit should lead to a weight loss of about 1 pound per week, which is a very healthy and sustainable weight loss.
I know it can be tempting to lower your daily calorie intake more if you are trying to lose weight, but it’s not a good idea. When you lose weight quickly by restricting your calories, you also lose muscle mass, and the weight you lose is much more likely to come right back (as fat) as soon as you stop dieting.
Instead, add more physical activity to your daily routine. Even just 15-30 minutes of light to moderate exercise such as walking can burn calories, increase your metabolism, and help you reach your goal weight.
To learn more about healthy calorie deficits, read our guide Can Eating Too Little Make You Gain Weight?
How many calories should you eat to gain weight (muscle)?
If you want to gain muscle, start out at 500 calories/day more than your maintenance calories and see what happens. If you find that you are also putting on a little too much fat, decrease your calories slightly.
Just like weight loss, healthy weight gain should happen slowly. If you want to gain weight and add muscle mass without adding (much) fat, focus on eating a healthy diet, incorporate exercise (and especially resistance training) into your daily routine, and aim for a caloric intake that’s only slightly higher than your maintenance calories.
How accurate is this formula?
While this calorie calculator is quite accurate for most people, it is based on an “average” person and therefore isn’t perfect for everyone.
It doesn’t take differences in natural metabolism into account, so if you have a particularly high or low metabolism (for example because of thyroid disease), the result from this formula won’t be accurate.
Because your natural metabolism declines as you age, the formula also tends to underestimate how many calories teenagers need and overestimate the daily calorie requirements for people older than 60.
It’s also the most accurate for people who are close to the “average weight”. If the result of your calculation is that you need less than 1,400 daily calories or more than 2,500 daily calories to maintain your current weight, then it’s recommended that you talk to your doctor or dietitian before making any changes to your diet.
Frequently asked questions
There are roughly 3,500 calories in 1 pound of body fat. This means that, in principle, you will lose 1 pound per week with a calorie deficit of 500 calories/day (3,500 calories/week).
In reality, weight reduction is often a little slower than this as your body adjusts dynamically to any calorie reductions by lowering your metabolism.
It can be very hard to know how much you are actually eating without counting calories. Research shows that people eating in fast-food restaurants underestimate how many calories are in their meal by up to 500 calories.
You can use apps such as MyFitnessPal or Lifesum to track your daily calorie intake (and daily activity).
To ensure you reach your daily calorie targets, it’s also a good idea to follow a meal plan. You can either create your own or simply pick one from my meal plan library.
5’7″ 53 yo F. 230 pounds. Your calculator says I should be eating 2642 calories per day. My doctor says I’m not allowed to eat any carbs due to triglycerides and diabetes. He won’t tell me what I’m allowed to eat. All he tells me is “avoid carbs”. Even if I only eat 10 grams of carbs with a meal he tells me I’m eating to much carbs and I need to watch it better. I’m scared to eat anything. Today I’ve had 2 cups of black coffee w/erythritol, 1 egg white and 1 stalk of celery. Is that too many carbs? I’m not allowed to eat carbs. Will it send my sugar too high? I’m afraid to check my sugar because it’s always too high and that only makes me feel like more of a failure and makes my anxiety worse. I’m afraid to eat and I’m desperate.
If you can I’d recommend you find another doctor and regardless get referred to talk to an RD (registered dietitian) and/or Certified Diabetes Care and Education Specialist (CDCES). I don’t think your doctor knows what he’s talking about.
Until then you can watch this interview I did with Toby Smithson, MS, RDN, LD, CDCES, FAND (https://youtu.be/j49XQStTfKo) and explore her resources
Hello Phenyxxfire, you must be feeling very upset not having your doctor give you the right guidance. You need the right information for what type of carbs you can eat. What you should try to do if you can is speak to a certified diabetic specialist. You may want to see, if possible, another Doctor. You need guidance, support and proper education not a scolding. You are not a failure, it’s just about learning to manage your diabetes and triglycerides. And this can be difficult but not impossible. I suggest you take note of everything you eat and at what times. This can help your future specialist see what you are consuming. You are not alone and you are not a failure. You can do this! Wishing you the best.
Katy RN
I am in same boat with the carbs but you need carbs too just right ones. Mostly you need make sure you eat other wise that will put your sugars out of walk too. I was doing 2 cups black coffee. I have hard time eating in morning so I am going to do my 2 cups coffee and a protien shake but I had look for one that didn’t have soy and whey which I found I am just waiting for it to come. I probably cary nuts with me for small snack before noon. The doctors I have want me eat 5 to 6 small meals to keep sugars balanced. Go to another doctor that will help you better then one you have now.
Find a new Dr. Your Dr should be helping you by giving you a meal plan. There are plenty of good diabetic cook books. A good diabetic plan is a balanced meal. AIM for low carb – try looking at “Keto” diets on Pinterest – those are mostly low carb options. Eat protein like chicken, ground turkey, eggs, almonds, cottage cheese. Avoid processed foods like lunch meat or other processed foods. Its a process – don’t freak out and starve yourself – just read more about diabetic meal plans.
Further to Christel’s point, your doctor is likely referring to “bad” carbs (also called simple carbs) which include pastries, pastas, etc. Complex carbs in veggies are healthy. And because he is not explaining this further emphasize’s Christel’s point to see a registered professional. All the best. You got this!!
I am 17 years old, my height is 5 feet 8.5 inches, my weight is 119 lbs,my body fats is around 7.5 to 8.5 percent. The main problem is that I am not able to build muscle. What should I do?
You don’t mention if you live with diabetes, but since that’s our primary focus here on Diabetes Strong, I’m adding the link to our article on how to build muscle with diabetes. Even if you don’t, much of the article is applicable to anyone https://diabetesstrong.com/gaining-muscle-with-type-1-diabetes-an-intro-guide/
Phenyxxfire, There is some good advise here. Personally, I don’t think your Doctor has done a very good job explaining what elevates your blood glucose. Carbs are just one factor. As suggested, a good registered dietitian could be very useful in giving you a plan and better understanding, as well as lessen your anxiety.
From experience, I was diagnosed with Type 2 last July. It was suggested that I look at the Keto Diet. With a some research I discovered an app, CarbManager.com. It has been a blessing. I dropped nearly 30% of my body weight (252 to 177 lbs) and my blood glucose from 160 to 90 mg/dl. I am no longer Type 2 or Pre-Diabetec. I also am on medication for high Cholestrol and high Triglycrtides which have also drop to normal levels. I feel better and am more activity without the stress and guilt.
Don’t despair, with knowledge and a little effort you can change where you are at. I found CarbManager gave me the direction and I found it very easy to follow. My appetite subsided and I discovered minor modifications to my menus left me satisfied and accomplished my health goals.
Good luck with your quest and happier day!
Thank you for the suggestion! I’m going to try it!
Hi, I’m female, 52 years old, 72kg and 1.63 cm
I’m trying to calculate my intake calories but i cant understand what u mean by 24 in your calculation???
Example using my stats: 61 kg (134.5 lbs.) x 0.9 (female) x24_x 0.95 (20% body fat) = 1252
can you explain for me pls thanks
We multiply by 24 to get your calorie needs for 24 hours. If you skip the step and don’t multiply by 24, you’ll have your hourly calorie need. In the calculation you have written out, all you need now is to multiply the 1252 with your activity factor step 5. If you’re not that active, that would then be 1252×1.3 = 1630 daily calories
i am 65 weigh 250 pounds. i am having trouble with my math. can you help me figure out my daily needs. i am very light in exercise.5’2 inches
Remember this formula is based on averages and should only be used as a starting point. Based on what you’ve told me your needs are probably around 2500-3000 calories per day
I am 37 years old Male. My weight is 130.9 kgs. And height is 5′ 11″ .As per calculations I need 3400 cal for daily maintenance of body
From 15 days I am taking intake of 1500 cal or some times less also
I lost 7 kgs
My question is that 1500 cal diet is good for me
Shall I continue same
Pls reply
I think it sounds on the low side. It’s probably not damaging in the short run, but you could try to increase it to 2000 calories for a week or two and see what type of results you get. Remember the calculator is meant as a starting point. It bases its recommendations on averages, and hardly anyone is average
Hi am 21 years old and am 5,9 I basically eat ones in a day but I still see my self adding weight I really don’t understand especially belle fat omg that the worst I really don’t know what to do I can wake up with a flat belle but ones I eat that first breakfast my belle comes out it really makes me sad 😞
Sounds like you’re really bloated. Everyone’s stomach will bulge out somewhat after we eat, especially if you only eat one large meal a day. You could try eating 2-3 smaller meals a day and pay attention to which types of food make you so bloated. Reducing or eliminating foods that irritate your stomach can for some help greatly with bloat
Hi, I’m 5.1 tall and I’m 21 years old. my weight is 126lb. I eat one Indian roti (bread), one sandwich with salad and a lot of water. sometime I just eat soup not an indian bread. 30min walk on treadmill. 3 exercises to burn fat but its doesn’t work for me. I want to lose weight and also burn fat from my hips and from my thighs. please guide me.
Doesn’t sound like you’re eating a lot. Starving yourself is not the way to go, it’s not sustainable or healthy. If you find that your body fat doesn’t change despite eating very little you should consult with your doctor and get your hormone levels tested. You might also benefit from working with a nutrition specialist such as an RD or fitness expert
I was recently told by my dr that I’m now diabetic. Not to the point of needing treatment yet, told me to lose some weight. I’m 56 years old, 5’8” and I weighed around 185 lbs when diagnosed. I’m now down to approximately 181 lbs. I’m confused with your formula. How can I figure my body fat %?
Well done on your weight management journey! If you scroll down to step 5 there’s a link to a body fat calculator
Hi, I’m 20 years old and I’m 4’11” and have had type 1 diabetes since I was 16. I have been trying to lose weight for almost a year and have seen no change at all. My friends tell me that I look more toned but that’s all. I weigh 128 lbs. I am very muscular but still I want to be smaller. Each day I eat an apple, a banana, a mini kind bar, a salad with almonds, cranberries, onion, tomato, and feta, and cauliflower rice with a pasta sauce. I usually eat 1000 calories per day. I also work out 5 days a week for about an hour each day (orange theory). I am so beyond frustrated with how I completely changed my lifestyle and still look the same. I see my roommates and friends eating way more than me and being so thin and I work so hard everyday. what more can I do and is my diet bad for weight loss?
Sounds like you’re undereating, which is not overall healthy.
The first step would probably be to get your hormones checked and see if everything is as it should be. If it is you can consider signing up with a qualified diabetes coach. I’d suggest you choose someone who has an RN degree and isn’t just winging it. A good option would be Ben Tzeel (ben@diabetesstrong.com).
The hard truth is probably that you’re not eating as little as you think you are or you might have thyroid issues. Both things are worth looking into.
Don’t give up
Hi Christel,
I am a 50 year old woman with type 1 diabetes since 2000. I am 155cm and 70kg. I am also in menopause for 2 years already. My blood sugars are not good but I have figured out my basal insulin needs as well as my carb ratio for the first meal. I would like to follow the 16 hour intermittent fasting program as well as a 50 grams carboyhydrates a day diet. My bodyfat is approx. 33%. Would you have any suggestions on how many calories I should eat daily to achieve a weight loss of 1 pound per week? And I really struggle with the macro thing so if you have a specific diet I could follow in the beginning that would be very helpful. Thank you in advance for your answer. And also thank you for having this website. What an inspiration!
Sincerley, Tina
If you use the methodology described here you should be able to calculate your daily calorie needs, it will probably be in the ballpark of 1800 calories/day, but you’ll have to run the calculation. Remember that’s based on the calculator not you as an individual, that means that it’s a starting point for finding your calorie needs. You can consume a few hundred less calories for 3-4 weeks and see if you’re tracking towards your goal, if not reduce your calories a bit more.
I wouldn’t worry too much about the macronutrients for now, but I think a good rule of thumb is to include a protein in every meal.
Hiya. I am a type 1 diabetic since the age of 6 and now I’m 38. I am 5 foot 3 (female) and I’ve been slim all my life, weighing between 47kg to 55kg. I had my last child 10 years ago and past 5 years, my weight has increased to 72kg. I look so big that its making me depressed. My BMR is 1329 and activity level makes this 1728. Can I make a deficit of 400 via diet alone/exercise only or combination of the 2? and should the deficit not go below my BMR?
Thank you
You can create a calorie deficit through diet and exercise or a combination. Whatever is easiest for you. Remember this calculator gives you a starting point, it’s not exact. Going below the calculated BMR occasionally shouldn’t hurt you but I wouldn’t recommend “living” in such an aggressive deficit
I’m 5’1 after my dieting i weighed 52.2kg I’ve been eating 800 calories for 2 months whilst also running 5k a day and doing 1 15 minute HITT workout a day, 10 min abs routine. I began to increase my calories to 850 and i’ve gained 1.2kg in two days what am i doing wrong?? i now weigh 53.4kg. I’m eating way below my maintenance and tracking my calories correctly
If you’ve increased your fiber content (more food and carbs) your body will store more water which most often explains rapid weight gain. Unless you have an underlying condition I’d assume that it’s a combination of water and waste and not be too concerned about it