Carbohydrate Calculator
Enter your daily calorie target and select a diet style to see your recommended carbohydrate intake in grams.
Reviewed by the ToolNestr Editorial Team — July 2026
Enter your calorie target and diet style to see your carb goal.
About carbohydrate intake
Carbohydrates are the body's preferred fuel source, especially for the brain and during high-intensity exercise. Despite the popularity of low-carb diets, carbs are not inherently unhealthy. The quality and quantity of carbohydrates matter. Whole-food carb sources provide fibre (which supports digestive health and satiety), vitamins and phytonutrients. Refined carbs from added sugars and white flour can spike blood sugar and contribute to metabolic problems when consumed in excess. This calculator helps you set a carb target that matches your lifestyle. For context on how carbs fit into your overall nutrition, pair with the Macro Calculator and Fat Intake Calculator.
⚕️ For general information only. Individual carb needs vary with activity, metabolism and health conditions.
How it works
Carbohydrates provide 4 calories per gram. This calculator multiplies your total daily calorie target by the carb percentage selected, then divides by 4 to get the gram target. For example, on a 2,500-calorie diet with a moderate 55% carb target: 2,500 × 0.55 = 1,375 calories from carbs, which equals 1,375 ÷ 4 = 344 g of carbs per day. The calculator adjusts the percentage based on your chosen diet style, from keto (5%) to endurance athlete (65%).
The formula explained
Carbs (g) = (total calories × carb%) ÷ 4
Fibre is an important part of carb intake — aim for at least 25–30 g of fibre per day for adults. Whole-food carb sources naturally provide fibre, while refined sources do not.
Worked example
A 70 kg endurance athlete eating 3,000 cal/day on a high-carb diet (65%) wants to know their carb target.
Marathon runner
High carb intake (60–65%) ensures muscles are fully glycogen-loaded for endurance events. Carbs are the key performance fuel for distance athletes.
Weight-loss seeker
A moderate or low-carb approach (30–45%) can help control appetite and blood sugar, making it easier to sustain a calorie deficit.
Strength athlete
Carbs fuel intense lifting sessions and support recovery. A moderate-high intake (50–55%) is typical for powerlifters and bodybuilders.
Type 2 diabetic
A moderate lower-carb approach (30–40%) with emphasis on low-glycaemic, fibre-rich sources can help with blood glucose management.
How to use this calculator
Set your calories
Enter your daily calorie target. Use the Calorie Calculator or TDEE Calculator if you need a starting point.
Choose carb level
Select the carb percentage that matches your activity level and dietary approach — from keto (5%) to high-carb endurance (65%).
Focus on quality
Fill your carb target with whole food sources — fruits, vegetables, whole grains and legumes. Minimise added sugars and refined grains.
Tips for healthy carb intake
Prioritise fibre
Aim for at least 25–30 g of fibre per day. Fibre slows digestion, stabilises blood sugar and promotes satiety. Whole plant foods are the best source.
Time carbs around exercise
Eating carbs 1–4 hours before exercise provides fuel. Post-workout carbs replenish glycogen stores. This is especially important for athletes training twice per day.
Limit added sugars
The WHO recommends keeping added sugars below 10% of total calories (ideally under 5%). For a 2,000-calorie diet, that is a maximum of 50 g of added sugar per day.
Related tools
Frequently asked questions
How many carbs should I eat per day?
The Dietary Guidelines recommend 45–65% of total calories from carbs. For a 2,000-calorie diet, that is 225–325 g per day. Active individuals need higher carb intake.
Are low-carb diets healthy?
Low-carb diets (20–30% of calories from carbs) can be effective for weight loss and blood sugar control for some people. However, they are not necessary or suitable for everyone. Very low-carb (keto) should be done with medical supervision.
Do I need carbs for exercise?
Yes — carbohydrates are the primary fuel source for high-intensity exercise. Athletes and active individuals need higher carb intakes to perform and recover. Low-carb training can feel significantly harder.
What are the best carb sources?
Whole food carb sources like fruits, vegetables, whole grains, legumes and starchy vegetables provide fibre, vitamins and minerals alongside energy. Refined carbs (white bread, sugary drinks) offer little nutritional value.
Can I eat carbs at night?
Yes — the idea that eating carbs at night causes weight gain is a myth. Total daily calorie intake determines weight change, not the timing of carbs. Eating carbs at night may even improve sleep quality for some people.
Sources & references
This tool uses standard formulas and reference values from:
- • NIH / National Institutes of Health and CDC reference values and formulas. nih.gov
- • Peer-reviewed equations (e.g. Mifflin-St Jeor, Harris-Benedict) as originally published.
- • ACOG for pregnancy, ovulation and due-date methodology. acog.org
Not medical advice. Estimates only — consult a qualified healthcare professional for any personal health decision.