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Carbohydrate Calculator — Free Online Daily Carb Intake Tool

Calculate your ideal daily carbohydrate intake based on your total energy expenditure and dietary approach. Choose from standard, moderate low-carb, low-carb, and ketogenic presets with full macronutrient breakdown.

Sex
kg
cm

Your Carb Results

296 - 428

grams of carbs per day

TDEE2,633 cal
Carb Calories1,185 - 1,711 cal
Carb Range45% - 65% of calories

Full Macro Breakdown

Carbs

362g

Protein

132g

Fat

73g

Summary: With a TDEE of 2,633 calories and a standard diet, you need approximately 296 to 428 grams of carbohydrates daily. Focus on complex carbohydrates from whole grains, vegetables, and legumes. Consult a healthcare provider before making significant dietary changes.

How to Use the Carbohydrate Calculator

  1. Select your unit system: Toggle between Metric (kg/cm) and Imperial (lbs/ft) at the top. The calculator adjusts all input fields based on your selection.
  2. Enter your personal details: Input your age, biological sex, weight, and height. These values calculate your Basal Metabolic Rate, which is then combined with your activity level to determine your Total Daily Energy Expenditure (TDEE) — the foundation for your carbohydrate recommendation.
  3. Select your activity level: Choose from five options ranging from Sedentary to Very Active. This determines how many total calories you burn daily, which directly affects how many grams of carbohydrates you need. A more active person requires more carbs to fuel exercise.
  4. Choose your diet type: Select the dietary approach that matches your goals or preferences. Standard (45-65% carbs) suits most people. Moderate Low-Carb (30-40%) provides modest carb reduction. Low-Carb (20-30%) suits those reducing carbs for weight management. Keto (5-10%) is for those pursuing nutritional ketosis. Each preset automatically adjusts protein and fat percentages to complement the carb allocation.
  5. Review your results: The results panel shows your recommended carbohydrate range in grams per day, TDEE, calorie range from carbs, and the percentage range for your selected diet type. Below, a full macro breakdown shows carb, protein, and fat targets with a visual distribution bar. For keto, a safety note is displayed. All values update instantly when you change any input.

Default values show results for a 30-year-old moderately active male on a standard diet. Replace these with your own data for personalized carbohydrate targets.

Carbohydrate Calculation Formula and Method

This calculator determines your carbohydrate needs by first calculating TDEE, then applying diet-specific macronutrient percentages.

Daily Carbs (g) = (TDEE x Carb%) / 4
TDEE = BMR x Activity Multiplier

Diet Type Configurations

  • Standard (45-65% carbs): Aligns with the Acceptable Macronutrient Distribution Range (AMDR) established by the National Academies. This is the most flexible approach, suitable for general health and most activity levels. Protein at 20%, fat at 25%.
  • Moderate Low-Carb (30-40% carbs): A mild reduction that can improve blood sugar control and may help with weight management while still providing ample fuel for moderate exercise. Protein increases to 30%, fat to 35%.
  • Low-Carb (20-30% carbs): A more significant reduction that encourages the body to use more fat for fuel. Effective for weight loss in many individuals but may reduce high-intensity exercise performance. Protein at 35%, fat at 40%.
  • Keto (5-10% carbs): Severe restriction designed to induce nutritional ketosis. The body shifts to burning fat and ketone bodies as its primary fuel source. Protein at 25%, fat at 70%. Requires careful planning and ideally medical supervision.

Step-by-Step Calculation Example

Consider a 35-year-old moderately active female (62 kg, 165 cm) following a standard diet:

  1. BMR: 10(62) + 6.25(165) - 5(35) - 161 = 620 + 1,031.25 - 175 - 161 = 1,315 cal/day
  2. TDEE (moderate, x1.55): 1,315 x 1.55 = 2,038 cal/day
  3. Carb range: 45-65% of 2,038 calories
  4. Minimum carbs: (2,038 x 0.45) / 4 = 229g
  5. Maximum carbs: (2,038 x 0.65) / 4 = 331g
  6. Midpoint: approximately 280g carbs per day

This woman needs approximately 229 to 331 grams of carbohydrates daily on a standard diet. The midpoint of 280g, combined with 102g protein (20%) and 57g fat (25%), totals her TDEE of approximately 2,038 calories. She can adjust within this range based on exercise intensity and personal preference.

Practical Examples

Example 1: Daniel Compares Standard vs. Low-Carb for Weight Loss

Daniel is a 38-year-old man (88 kg, 180 cm) who exercises 3 times per week. He wants to compare how many carbs he would eat on a standard diet versus a low-carb approach:

  • TDEE (moderate): 1,823 x 1.55 = 2,826 cal/day
  • Standard (45-65%): 318-459g carbs | ~389g midpoint
  • Low-Carb (20-30%): 141-212g carbs | ~177g midpoint
  • Difference: approximately 212 fewer grams of carbs per day

Daniel decides to start with the moderate low-carb option (30-40%) as a comfortable middle ground, giving him approximately 212-283g of carbs daily. He finds this sustainable because he can still eat whole grain bread, rice, and fruit — just in smaller portions than before. He focuses on replacing refined carbs (white bread, pasta, sugary snacks) with complex carbs (sweet potatoes, quinoa, beans) rather than eliminating entire food groups.

Example 2: Sofia Fuels Marathon Training with Carbs

Sofia is a 30-year-old woman (58 kg, 170 cm) training for a marathon. She runs 6 days per week with long runs on weekends (very active):

  • TDEE (very active, x1.9): 1,351 x 1.9 = 2,567 cal/day
  • Standard high-carb (55-65%): 353-417g carbs
  • She targets 60% carbs: 385g carbs per day
  • Protein (20%): 128g | Fat (20%): 57g

Sofia needs high carbohydrate intake to fuel her training. Muscle glycogen is the primary fuel for running at moderate to high intensity, and depleted stores lead to the dreaded "bonking" or "hitting the wall." She consumes extra carbs before long runs (carb loading) and uses sports drinks and gels during runs over 60 minutes. Her diet centers on oatmeal, rice, pasta, bread, bananas, and sweet potatoes. She also uses the TDEE calculator to adjust calories during taper weeks when training volume decreases before the race.

Example 3: Robert Tries a Ketogenic Approach

Robert is a 45-year-old man (92 kg, 178 cm) with prediabetes. His doctor suggests exploring a low-carbohydrate approach to improve blood sugar control. He uses the keto preset:

  • TDEE (sedentary, x1.2): 1,825 x 1.2 = 2,190 cal/day
  • Keto (5-10%): 27-55g carbs per day
  • He targets 40g carbs: approximately 40g carbs, 137g protein, 170g fat

Robert's 40g daily carb target means he must eliminate most grains, starchy vegetables, fruits (except small portions of berries), and all sugary foods. His carbs come from non-starchy vegetables (broccoli, spinach, cauliflower, peppers), nuts, seeds, and small amounts of dairy. His fat intake comes from olive oil, avocado, fatty fish, cheese, and butter. He works closely with his doctor to monitor blood sugar and medication adjustments, as the keto diet can significantly reduce blood glucose levels and may require medication dose changes.

Carbohydrate Sources Reference Table

Food Serving Total Carbs (g) Fiber (g) GI Rating
Brown Rice (cooked) 1 cup 45g 3.5g Medium (68)
Sweet Potato (baked) 1 medium 26g 3.8g Medium (63)
Oats (dry) 1/2 cup 27g 4g Low (55)
Quinoa (cooked) 1 cup 39g 5g Low (53)
Lentils (cooked) 1 cup 40g 15.6g Low (32)
Banana 1 medium 27g 3.1g Medium (62)
Whole Wheat Bread 1 slice 12g 1.9g Medium (69)
Apple 1 medium 25g 4.4g Low (36)
Broccoli 1 cup 6g 2.4g Low (15)
White Rice (cooked) 1 cup 45g 0.6g High (73)

Values are approximate. GI values vary by preparation method and variety. USDA FoodData Central and the International GI Database used as references.

Tips and Complete Guide to Carbohydrate Intake

Understanding Your Body's Carbohydrate Needs

Carbohydrates are your body's preferred and most efficient fuel source. When you eat carbs, your digestive system breaks them down into glucose, which enters your bloodstream and is used by cells for energy. Excess glucose is stored as glycogen in your liver (approximately 100g capacity) and muscles (approximately 400g capacity). Once glycogen stores are full, additional excess glucose is converted to fat. Your brain alone requires approximately 120 grams of glucose daily, which is why extremely low-carb diets can initially cause brain fog, headaches, and difficulty concentrating until the brain adapts to using ketone bodies (a process that takes 2-4 weeks). The amount of carbs you need depends primarily on your activity level — the more physically active you are, the more glycogen you use and need to replenish.

Choosing the Right Diet Type

The standard diet (45-65% carbs) works well for most people and is the easiest to sustain long-term. It supports all types of exercise and provides ample fiber and micronutrients from carb-rich whole foods. Moderate low-carb (30-40%) is a good starting point for those who want modest carb reduction without the restrictiveness of full low-carb — it still allows whole grains, fruits, and starchy vegetables in controlled portions. Low-carb (20-30%) can accelerate fat loss and improve insulin sensitivity but may reduce high-intensity exercise performance until your body adapts. Keto (5-10%) produces the most dramatic metabolic shift but is the hardest to maintain, requires careful meal planning, and should include medical oversight if you have any health conditions. Consider your lifestyle, food preferences, exercise type, and how long you plan to follow the diet when choosing.

Carbs and Exercise Performance

The relationship between carbohydrates and exercise is well-established in sports science. During moderate to high-intensity exercise, muscle glycogen is the primary fuel source. Inadequate carbohydrate intake leads to premature fatigue, reduced power output, impaired concentration, and slower recovery. The American College of Sports Medicine recommends 3-5 g/kg/day for general fitness, 5-7 g/kg/day for moderate exercise (1 hour daily), 6-10 g/kg/day for endurance training (1-3 hours daily), and 8-12 g/kg/day for extreme training (4-5+ hours daily). For weight training focused on hypertrophy, ensuring adequate carbs pre- and post-workout supports both performance and recovery. Use the macro calculator to see your full macronutrient breakdown based on your fitness goal.

Carbohydrates and Blood Sugar Management

For people with diabetes or prediabetes, managing carbohydrate intake is particularly important. Carbohydrates have the most direct impact on blood glucose levels compared to protein and fat. The American Diabetes Association does not prescribe a specific carbohydrate percentage but recommends consistent carb intake at meals, choosing high-fiber complex carbohydrates over refined sources, and monitoring blood glucose responses to different foods. Carb counting is a common strategy where each meal targets a consistent number of carb grams (often 30-60g per meal). Pairing carbohydrates with protein and fat slows glucose absorption and reduces blood sugar spikes. If you are managing blood sugar, use this calculator with the moderate low-carb or low-carb preset and discuss the results with your healthcare provider.

Common Mistakes to Avoid

  • Fearing all carbohydrates equally: There is a significant difference between a bowl of steel-cut oats with berries and a can of soda, even though both are "carbs." Whole food carbohydrate sources provide fiber, vitamins, minerals, and antioxidants alongside energy. Refined and added sugars provide empty calories. Reduce refined carbs before cutting whole food sources.
  • Going too low too fast: Dramatically cutting carbs overnight leads to the "keto flu" — headaches, fatigue, irritability, and brain fog as your body adapts. If reducing carbs, decrease intake gradually by 25-50g per week over several weeks. This allows your enzymes and metabolic pathways time to adapt to using more fat for fuel.
  • Ignoring fiber when counting carbs: If you cut carbs aggressively, fiber intake often drops because many high-fiber foods (beans, whole grains, fruits) are also high in carbs. Low fiber intake causes constipation, poor gut microbiome health, and reduced satiety. Even on low-carb diets, prioritize fiber-rich vegetables and consider supplementing with psyllium husk if needed.
  • Not adjusting carbs for training days: A rigid daily carb target ignores the fact that your body's carbohydrate needs vary based on that day's physical activity. On intense training days, your muscles may use 200-500 calories worth of glycogen that needs replenishing. On rest days, your needs are lower. Consider a flexible approach with higher carbs on training days and lower carbs on rest days.
  • Judging success too quickly: When reducing carbs, the initial 2-5 pounds of weight loss is primarily water (each gram of glycogen is stored with 3-4 grams of water). This rapid loss can create unrealistic expectations. Judge the effectiveness of your carb level by tracking weight trends over 4+ weeks, not the first week's dramatic change.

Frequently Asked Questions

Daily carbohydrate needs depend on your total calorie expenditure and dietary approach. The Dietary Guidelines for Americans recommend that 45% to 65% of total calories come from carbohydrates, which for a 2,000-calorie diet translates to 225 to 325 grams per day. Athletes and highly active individuals may need higher amounts (55-65% of calories) to fuel performance. People following low-carb diets typically consume 20-30% of calories from carbs (100-150g on a 2,000-calorie diet), while those on ketogenic diets restrict to 5-10% (20-50g). This calculator adjusts recommendations based on your TDEE and selected diet type.

Simple carbohydrates consist of one or two sugar molecules (monosaccharides and disaccharides) and are digested rapidly, causing quick spikes in blood sugar. Examples include table sugar, honey, fruit juice, candy, and soda. Complex carbohydrates (polysaccharides) contain longer chains of sugar molecules and take longer to digest, providing sustained energy with smaller blood sugar fluctuations. Examples include whole grains (oats, brown rice, quinoa), legumes (lentils, beans, chickpeas), starchy vegetables (sweet potatoes, corn), and whole-grain bread and pasta. A third category, fiber, is a complex carbohydrate that humans cannot fully digest but provides critical benefits for gut health, blood sugar regulation, and heart health.

Carbohydrates themselves do not cause weight gain — excess calories from any source do. Research consistently shows that weight loss is determined by calorie balance, not carbohydrate intake specifically. Low-carb diets can be effective for weight loss, but they work primarily because reducing carbs often reduces total calorie intake, not because carbohydrates are inherently fattening. A 2018 Stanford study (DIETFITS) compared low-carb and low-fat diets over 12 months and found no significant difference in weight loss between the two approaches when calories were equivalent. The best approach is the one you can sustain long-term. If you enjoy grains, fruits, and starchy vegetables, a moderate-carb diet (40-50% carbs) with a calorie deficit will produce the same weight loss results as a low-carb approach.

The Glycemic Index (GI) is a scale from 0 to 100 that measures how quickly a carbohydrate-containing food raises blood glucose levels compared to pure glucose (GI = 100). Low GI foods (55 or below) include most fruits, legumes, non-starchy vegetables, and whole grains. Medium GI foods (56-69) include whole wheat bread, brown rice, and sweet potatoes. High GI foods (70+) include white bread, white rice, sugary cereals, and potatoes. Lower GI foods generally provide more sustained energy and smaller blood sugar fluctuations. However, the GI of a food changes when eaten in combination with protein and fat, which slow digestion. Glycemic Load (GL) is often more practical, as it considers both the GI and the amount of carbohydrates in a typical serving.

A standard ketogenic diet restricts carbohydrate intake to 20 to 50 grams per day, or approximately 5% to 10% of total calories. This severe restriction forces the body to enter ketosis, a metabolic state where fat is broken down into ketone bodies for fuel instead of relying on glucose from carbohydrates. Most of these carbs should come from non-starchy vegetables, nuts, seeds, and small amounts of berries. A typical keto day might include 15g of net carbs from vegetables (leafy greens, broccoli, cauliflower), 5g from nuts and seeds, and 5g from dairy. A keto diet should be undertaken with guidance from a healthcare provider, particularly for people with diabetes, kidney disease, or a history of eating disorders.

Fiber is a type of carbohydrate that your body cannot fully digest. Soluble fiber (found in oats, beans, apples, and citrus fruits) dissolves in water and forms a gel that slows digestion, helping regulate blood sugar and lower cholesterol. Insoluble fiber (found in whole wheat, nuts, vegetables, and bran) does not dissolve and adds bulk to stool, promoting regular bowel movements and gut health. The Academy of Nutrition and Dietetics recommends 25 grams per day for women and 38 grams per day for men. Most Americans consume only about 15 grams daily. To increase fiber intake gradually (too fast can cause bloating), add more whole grains, legumes, fruits, and vegetables to your diet, and drink extra water to help fiber move through your digestive system.

Net carbs are calculated by subtracting fiber (and sometimes sugar alcohols) from total carbohydrates, since fiber is not digested and does not significantly affect blood sugar. For most people eating a standard diet, tracking total carbs is sufficient. However, those following low-carb or ketogenic diets often track net carbs because fiber should be encouraged even on restricted diets — a cup of broccoli has 6g total carbs but only 2.4g net carbs after subtracting 3.6g of fiber. Be cautious with sugar alcohols (erythritol, xylitol, maltitol) — they vary widely in their glycemic impact. Erythritol has virtually no effect and can be fully subtracted, while maltitol has a significant glycemic impact and should be partially counted.

Carbohydrate timing matters most for athletes and people managing blood sugar. For exercise performance, consuming carbohydrates 1 to 4 hours before exercise provides fuel for the session, and consuming carbs within 30 to 60 minutes after exercise replenishes depleted muscle glycogen stores — this post-workout window is when your muscles are most receptive to glucose uptake. For blood sugar management, distributing carbs evenly across meals prevents large glucose spikes. For most people, timing is less important than total daily intake and quality. One evidence-based approach is carb cycling: eating more carbs on training days (to fuel workouts) and fewer on rest days (when glycogen demands are lower). This strategy naturally aligns carb intake with energy expenditure.

Related Calculators

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Disclaimer: This calculator is for informational purposes only and does not constitute medical advice. Consult a qualified healthcare professional for medical guidance.

Last updated: February 23, 2026

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