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.
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.
Joseph
Hi I work as a plumber and it’s quite a demanding job I easily surpass 10,000 steps every day, i also play soccer twice a week and use the gym 5 days a week, I’m 11st 5lbs (72kg) and I am 5ft 8 inches (172 cm) do you think 2300 cals per day in a deficit is too low especially because I play a sport because I do be so hungry on this amount of calories and this was given to me by a PT?
Christel Oerum
It all depends on what your goals are. If you athletic performance is suffering it might not be worth it.
The way to think of these calculators is that they can help you establish a baseline and you can then dial in your calories from there
Lidi
I am 5’2, female, 30 y/o, on a insulin pump, I weight 77kg and I am 7 month postpartum. I was 65kg before pregnancy. I been having such a difficult time to lose the weight I gained. Also, I am taking 100-120 units of insulin which my doctors and myself can’t figure out what’s going on. I wasn’t taking so much before pregnancy. I am frustrated at this point and don’t know what meal plans, diets to follow. I feel like though my doctor and diabetic educator are professionals, they don’t understand the struggle it is to be a diabetic and lose weight. My doctor tell me that my insulin resistant is due to the weight I have over, but I don’t know how to lose it. I have been eating clean and I see no weight loss!
Christel Oerum
I understand your frustration.
Your insulin needs do correlate strongly with your bodyweight so what your medical team is telling you makes sense. Since your goal is fat loss I”d suggest you focus on being in a calorie deficit and managing your blood sugars. Eating healthy, or “clean”, isn’t enough if you’re not in a calorie deficit.
Further, fat loss is a process that takes time, so you need to be patient and kind to yourself.
Gabrielle
Hi, my name is Gabrielle. I’m 16 and I’ve had type one since I was 2. I do intense training workouts 6 days a week, and at least an hour a day (I’ve been fighting in a combat sport at a national level for about 5 years so I need this type of training). I usually eat no more than 1500 calories a day yet I cannot lose weight no matter what I do unless I fast but then I gain that weight right back. I’m currently 5’5 and 130 pounds, and I’m trying to get to at least 120. My A1C is 6.8. Do you have any recommendations that could help me?
Christel Oerum
High level, assuming all your hormone levels are tightly managed (your endo should be keeping an eye on that), the order of things to focus on is blood sugar management and then your calorie balance.
But I’d also suggest you give some thought to why you want to be 120 lbs. Since you’re a fighter I’m sure you carry some healthy muscle which might make your current weight the right level for you. But of course, if you’re leaning out for a fight the exact number on the scale will be important.
You might benefit from working with a trained professional who can look at your diabetes, exercise, and nutrition all at once. I’d recommend reaching out to Ben Tzeel our Fitness Editor (ben@diabetesstrong.com).
Ritu Kumari Singh
Hey Christel my age is 21 and height is 5.1 feet and weight 45 kg. I want to stay fit so could you help me out for my diet and exercises.
Christel Oerum
Sounds like you’re looking for a personal trainer with diabetes experience. I don’t do personal training but recommend that you reach out to our Fitness Editor Ben Tzeel, you can read more about him here: https://diabetesstrong.com/about-us/
If you’d like to talk to him please email us at contact@diabetesstrong.com
Ritu
Hello My name is Ritu, I jave accessive fats on my belly and got double chin too. My hands and legs are lean. I am 29 and weigh 68Kgs. My height is 168cms. I want to start to reduce calories I intake and improve my diet. Could you please help me.
Christel Oerum
Unfortunately, you can’t spot reduce your fat loss (except through surgery). So you’ll have to focus on losing overall body fat and those areas will shrink as well
Jaz
Hello! I’m 70kg x 1.73m, 30 years old. I’ve been eating 400-500 calories less than my calories intake total (which is 2200 cal) to lose fat, I’ve lost only 1kg in 4 months (doing exercises too although I’m not that active anymore due the lockdown).
Now I’ve decided to have 2200, working hard on a hiit program 4-5 times a week and I’ve noticed the weight is going down. Is it possible that eating more calories is helping to burn fat some how? I always though the rule to lose fat was a significant deficit. Many thanks 🙂 Jaz
Christel Oerum
Different things could be going on. You might be moving more now that you’re not undereating, both during your workouts and during the day. Many tend to (without even noticing) reduce their overall activity when in a significant calorie deficit. I’ve also seen stress levels go down when calories were increased helping with weight loss. And finally, weight loss isn’t linear so maybe that’s what you’re seeing.
Regardless you’ve found your sweet post, that’s awesome! Keep up the good work
SALMA CHERFAN
hello, my name is Salma and I would like to diet on a 700calorie diet per day
I am a Diabetic T2. I heard Dr David Lloyd advise people like me to lose 20kg on this 700Cal per day. The diets available are full of stuff that I do not eat.For example Peanut butter,Sandwiches,American food stuff. My diet is mainly grilled food and lots of salad.Thanks
Christel Oerum
I would generally not recommend any of the extreme diets such as the one you’re mentioning here. If you’re to eat such low calories you should be monitored closely by a medical professional
juliana
Dear Christel
I exercise 4 days a week including cardio at gym and sometimes burn 300 – 400 calories in the machines .
I put my daily activity as Moderate . My BRM is 1080 and I need 1947 calories a day . And on the fitness pal When i burn 350 or 400 calories i need 2000 calories .
Did I put my activity level right ?
Christel Oerum
Remember this is just a calculator that will help you estimate your needs. It’s what I’d call a good starting point, so try it out for a few weeks and adjust if needed.
As for MFP, no I don’t recommend adding in the calories burned to the calorie goal as it’s already included in the calculation
Debbie Albright
Hello. I’m a 65 yr old with type 1 Diabetes. I’ve struggled my entire life trying to reduce my weight. I’ve finally settled on a low carb diet of about 1,000/day. My HA1C last week was 6.5, and I weigh 150. I have a 15 min resistance exercise routine and a 3 mile walk almost daily. My Endocrinologist is thrilled with me. I generally do not eat before 3:00-4:30pm daily. (I am not hungry.) My difficulties come every 4 days or so….i feel the need for a mid day meal, and then I usually over eat. I spend a lot of time watching my sensor data on those days. Needless to say, my weight does not change. Is it fair to say I should give up this quest. It’s been a very long haul getting to this point in life, and I’d like to come to peace with this challenge. Thank you
Charbel Younes
I’m 171 cm tall, 22 y.o, 75 kg, ~15% bf, and according to the formula, I need 2821.5 calories daily. I’m a little surprised, how can you explain that please ?
75 x 1 x 24 x 0.95= 1710
1710 x 1.65= 2821.5
I thought my caloric need was way less.
Christel Oerum
It’s a formula based on the majority of the population. Given your age, most formulas will assume you have a high BMR. I’d say that most people overestimate their activity level and should use the 1.3-1.55 activity multiplier, which would put you at 2223-2650 calories. I don’t know you or your lifestyle, but if you’re active I don[‘t think the 2800 calories is a bad starting point
Charbel Younes
Deal. Thank you and merry christmas & a new year full of success
Vishnu
ma’am my hight is 182 cm and weight is 60 kg I want increase my weight approximately 80 kg . May you help me
Christel Oerum
You’ll need to increase your caloric intake. If you’re looking to add muscles I would suggest focusing on lifting weights and eating in a surplus