Daily carb target from calories — enter carbs in any mass unit.
Carbs_g = (TDEE × Carb%) / 4
Your daily carbohydrate target in grams is derived from two pieces of information: (1) your Total Daily Energy Expenditure (TDEE) in kilocalories, and (2) the percentage of total calories you want to come from carbohydrates. Because each gram of carbohydrate provides exactly 4 kilocalories of energy, you divide the carbohydrate calorie share by 4 to convert to grams.
TDEE itself is calculated using the Mifflin–St Jeor equation (the most validated resting metabolic rate formula) multiplied by an activity factor:
Activity factors: Sedentary 1.2 · Lightly active 1.375 · Moderately active 1.55 · Very active 1.725 · Extra active 1.9
Step 1 – RMR (Mifflin–St Jeor, female): RMR = (10 × 68) + (6.25 × 165) − (5 × 35) − 161 RMR = 680 + 1031.25 − 175 − 161 = 1375 kcal Step 2 – TDEE: TDEE = 1375 × 1.55 = 2131 kcal Step 3 – Daily carb grams: Carbs_g = (2131 × 0.50) / 4 = 1065.5 / 4 ≈ 266 g
Result: **Approximately 266 g of carbohydrates per day**, supplying ~1066 kcal from carbs out of a 2131 kcal daily budget.
A result of 266 g of carbohydrates per day means this person should aim to consume roughly 266 grams of total carbohydrates — including starches, sugars, and dietary fibre — across all meals and snacks each day. At 50 % of a 2131-calorie budget, this is consistent with mainstream dietary guidelines (45–65 % from carbs per the Dietary Guidelines for Americans). If the goal were weight loss, she might lower the carb percentage to 35–40 %, reducing the target to roughly 187–213 g/day, while ensuring adequate protein and healthy fats fill the remaining calories. Always monitor energy, performance, and wellbeing when adjusting macros.
Carbohydrates are the body's preferred fuel source, especially for the brain (which uses ~120 g/day alone) and high-intensity exercise. They are stored as glycogen in the liver (~100 g) and muscles (~400 g), providing a readily available energy reserve.
The Dietary Guidelines for Americans (2020–2025) recommend that 45–65 % of total daily calories come from carbohydrates for most healthy adults. This equates to 225–325 g/day on a 2000-calorie diet. The Institute of Medicine sets the Recommended Dietary Allowance (RDA) for carbohydrates at a minimum of 130 g/day for adults and children — the amount needed to fuel the brain without relying on ketogenesis.
| Diet Style | Carb % of Calories | Approx. Grams (2000 kcal diet) | |---|---|---| | Standard / Balanced | 45–65 % | 225–325 g | | Moderate Low-Carb | 26–44 % | 130–220 g | | Low-Carb | 10–25 % | 50–125 g | | Very Low-Carb / Ketogenic | < 10 % | < 50 g |
Focus on complex, fibre-rich carbohydrates — wholegrains, legumes, vegetables, and fruit — rather than refined sugars and white starches. The Dietary Guidelines recommend at least 14 g of dietary fibre per 1000 kcal consumed.
This calculator is educational only. Consult a registered dietitian or qualified healthcare professional before making significant dietary changes.
Carbohydrates do not inherently cause weight gain — excess calories do. Weight gain occurs when total calorie intake exceeds expenditure regardless of macronutrient source. However, refined, high-glycaemic carbohydrates can promote overeating by causing rapid blood glucose swings, making it easier to exceed your calorie target.
There is no single answer, but reducing carbohydrates to 26–40 % of calories (roughly 130–200 g/day on a 2000-calorie diet) while maintaining adequate protein (1.6–2.2 g/kg) is a practical, evidence-supported approach. The most important factor is creating a sustained calorie deficit of 300–500 kcal/day.
Yes. 100 g/day is generally classified as low-carb, sitting well below the standard recommendation of 225–325 g/day for a 2000-calorie diet. It is above the ketogenic threshold of 20–50 g/day, so it typically does not induce full ketosis but can still support fat loss and improved blood sugar control.
A common approach is to distribute carbs in proportion to energy needs throughout the day: a moderate amount at breakfast, the largest serving around the most active period (pre- or post-workout), and a smaller amount in the evening. This aligns carb intake with insulin sensitivity, which tends to be highest in the morning and after exercise.
For most healthy adults, dietary guidelines recommend 45–65 % of daily calories from carbohydrates. On a 2000-calorie diet that equates to 225–325 g per day. Your personal target will differ based on your TDEE, activity level, and health goals.
The Institute of Medicine sets the RDA for carbohydrates at 130 g/day — the minimum needed to fuel the brain adequately without relying on ketone production. Very low-carb ketogenic diets deliberately go below this threshold, but should be undertaken with medical supervision.
The calculator uses the Mifflin–St Jeor equation to estimate your Resting Metabolic Rate from your age, sex, height, and weight. It then multiplies this by an activity factor (1.2 to 1.9) based on your weekly exercise level to estimate total daily calorie expenditure.
Yes. Simply enter a carbohydrate percentage of 5 % (or whatever your specific keto target is). For a 2000-calorie diet at 5 %, that gives approximately 25 g of carbs per day, which is within the typical ketogenic range of 20–50 g/day.
This calculator outputs total carbohydrates. If you follow a low-carb or ketogenic approach, many practitioners track net carbs (total carbs minus dietary fibre, and sometimes minus sugar alcohols) because fibre is not digested and absorbed for energy in the same way.
Recalculate whenever your weight changes by more than 2–3 kg, your activity level shifts significantly, or your dietary goals change. For active weight-loss phases, every 4–6 weeks is a reasonable cadence.
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