Carbohydrate Calculator
Work out how many grams of carbohydrates to aim for each day. We estimate your daily calorie burn, then split out the carb share you choose.
Your details
How to use this calculator
1. Pick your unit system
Switch between metric (kg / cm) and imperial (lb / ft·in). Enter your age and gender too — they feed the calorie estimate that drives your carb target.
2. Set your activity level
Choose the option that best matches a typical week. More activity raises your estimated calorie burn, which raises the grams of carbohydrate you can eat at the same percentage.
3. Choose a carb percentage
Pick 45%, the recommended 50%, or 65% of calories from carbs — or enter a custom value. The result updates instantly with a recommended gram target and a low-to-high range.
4. Combine with the other macros
Carbs are only one piece. To balance carbs, protein, and fat together, try our macro calculator and treat these numbers as a starting point you adjust over time.
About carbohydrate needs
How many carbs should I eat per day?
A common guideline puts carbohydrates at 45% to 65% of total daily calories. This tool estimates your daily energy needs, multiplies by the percentage you pick, and divides by 4 (carbs supply about 4 calories per gram) to get grams per day. Your real needs depend on activity, body composition, and goals.
How is the calorie estimate made?
We calculate your Basal Metabolic Rate with the Mifflin-St Jeor equation, then multiply by an activity factor to get Total Daily Energy Expenditure (TDEE). The carb percentage you choose is applied to that calorie total.
Does this replace advice from a dietitian?
No. This is an educational estimate, not medical or nutritional advice. People managing diabetes, kidney disease, or other conditions should follow targets set by a qualified healthcare professional or registered dietitian.