Carbohydrate Calculator

Calculate your optimal daily carbohydrate intake based on your TDEE, activity level, and dietary goals.

Free to use. Runs in your browser.

Enter your daily calorie target to see recommended grams of carbohydrates. Most adults thrive on 45 to 65% of calories from carbs, about 225 to 325 g on a 2,000 kcal diet.

Calculate Carbohydrate Intake

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Educational Estimates Only: These calculations are approximations based on population-level formulas and may not accurately reflect your individual health status. Body composition varies significantly due to factors like muscle mass, bone density, hydration, and ethnicity. This is not medical advice. Always consult a qualified healthcare provider for personalized assessment, diagnosis, or treatment decisions.

Carbs Aren't the Problem, The Wrong Carbs Are

Carbohydrates have become the most misunderstood macronutrient. Keto enthusiasts demonise them. Marathon runners worship them. The truth, as usual, is in the middle.

Carbs are your body's preferred energy source. Your brain alone uses 120g of glucose per day, about 60% of all the carbs a sedentary person needs. During high-intensity exercise, carbs are the only fuel your muscles can burn fast enough to sustain the effort. Try sprinting on an empty glycogen tank and you'll understand why.

The real question isn't "should I eat carbs?" but "which carbs, and how many for my goals?" A sedentary office worker and a marathon runner have wildly different needs. This calculator gives you a personalised target based on your actual energy expenditure and goals.

Simple vs Complex Carbs

Type	Examples	Digestion Speed	Best For
Simple (high GI)	White bread, sugar, fruit juice, sweets	Fast, blood sugar spikes quickly	During/immediately after exercise
Complex (low GI)	Oats, brown rice, sweet potato, lentils, vegetables	Slow, sustained energy release	Most meals throughout the day
Fibre	Vegetables, whole grains, beans, nuts	Not fully digested, feeds gut bacteria	Every meal (aim for 25 to 35g/day)

What this means for you: Get 80% of your carbs from complex sources. The fibre slows digestion, keeps you fuller for longer, feeds beneficial gut bacteria, and prevents the blood sugar crashes that lead to afternoon energy slumps. Save simple carbs for during or right after exercise, when fast energy delivery is an advantage.

Carb Needs by Activity Level

Activity Level	Carbs (g/kg/day)	Example (75 kg person)
Sedentary / low-carb diet	2 to 3 g/kg	150 to 225g
Light exercise (30 min/day)	3 to 5 g/kg	225 to 375g
Moderate exercise (1 hr/day)	5 to 7 g/kg	375 to 525g
Heavy training (1 to 3 hrs/day)	6 to 10 g/kg	450 to 750g
Extreme (4+ hrs/day)	8 to 12 g/kg	600 to 900g

Source: International Society of Sports Nutrition. These are guidelines, not rigid targets. If you're trying to lose weight, the lower end of your range creates a calorie deficit. If you're trying to fuel performance, aim for the higher end. Use our TDEE Calculator to find your total calorie target first.

Carb Timing for Exercise

Pre-Workout (2 to 3 hours before)

Eat a meal with 1 to 2g carbs per kg of body weight. Choose complex carbs for sustained energy: oatmeal, rice, or whole grain toast. If eating closer to training (30 to 60 min), keep it smaller and simpler: a banana or a handful of dried fruit.

During Exercise (60+ min sessions)

For sessions over 60 minutes, consume 30 to 60g carbs per hour. Sports drinks, gels, or dried fruit work well. For ultra-endurance events (3+ hours), trained athletes can absorb up to 90g/hour using mixed glucose + fructose sources.

Post-Workout (within 2 hours)

Replenish glycogen with 1 to 1.5g carbs per kg. This is the one time simple carbs are ideal, the fast absorption accelerates glycogen resynthesis. Combine with protein (0.3g/kg) for enhanced recovery.

Rest Days

Reduce carb intake to the lower end of your range. Your muscles aren't depleting glycogen, so they need less replenishment. Focus on complex carbs with fibre and reduce simple carbs to keep blood sugar stable.

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How to use this tool

Select your preferred unit system

Enter your age, gender, height, and weight

Choose your activity level and dietary goal

Common uses

Setting daily carb targets by dietary goal
Planning low-carb or ketogenic diets
Fuelling endurance training and recovery
Managing blood sugar through diet
Balancing macros for body composition

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Frequently Asked Questions

How many carbs should I eat per day?

The Dietary Guidelines recommend 45 to 65% of total calories from carbohydrates, which works out to 225 to 325 g on a 2,000 kcal diet. Your exact target depends on activity level, body composition goals, and metabolic health.

Are low-carb diets effective for weight loss?

Low-carb diets (under 130 g/day) can be effective for weight loss and blood sugar management. They tend to reduce appetite and cause rapid initial weight loss, though much of the early drop is water. Long-term, total calorie deficit matters more than carb percentage.

What's the difference between simple and complex carbs?

Simple carbs (sugar, white bread, fruit juice) digest quickly and spike blood sugar. Complex carbs (whole grains, vegetables, legumes) provide sustained energy, more fibre, and a gentler blood sugar response. Most of your carbs should come from complex sources.

Do I need carbs to build muscle?

Yes. Carbohydrates fuel resistance training and replenish muscle glycogen afterward. Most strength athletes consume 40 to 60% of calories from carbs during building phases. Going too low on carbs can impair training intensity and recovery.

How does activity level affect carb needs?

Sedentary individuals need 3 to 5 g/kg/day, recreational exercisers need 5 to 7 g/kg, and endurance athletes may need 7 to 12 g/kg to fuel training and recovery. The more active you are, the more glycogen you burn and need to replace.

What is the glycaemic index and why does it matter?

The glycaemic index (GI) ranks carbs from 0 to 100 by how fast they raise blood sugar. Low-GI foods (under 55) provide steady energy, while high-GI foods (above 70) spike blood sugar quickly. Choose low-to-moderate GI for most meals; high-GI is useful immediately after intense exercise.

How many carbs should I eat before a workout?

Eat 1 to 4 g per kg of bodyweight 1 to 4 hours before exercise. Closer to the workout, choose simpler carbs that digest quickly (banana, white rice, toast). Further out, complex carbs with protein work well (oatmeal, wholegrain sandwich).

Are carbs bad for weight loss?

No. Carbs themselves don't cause weight gain, a calorie surplus does. Cutting carbs reduces calories, but you'd lose the same weight cutting the same calories from fat. Carb quality matters more than carb quantity for most people.

How much fibre should I eat per day?

Adults should aim for 25 to 30 g of fibre daily, though most people only get 15 to 18 g. Fibre comes exclusively from carbohydrate-containing foods, whole grains, vegetables, fruits, legumes, nuts, and seeds.

What are net carbs?

Net carbs are total carbohydrates minus fibre (and sometimes sugar alcohols). The idea is that fibre isn't digested for energy, so it shouldn't 'count.' Keto dieters typically track net carbs, aiming for 20 to 50 g/day.

Do I need to carb-load before a marathon?

For events lasting over 90 minutes, carb-loading (8 to 12 g/kg/day for 1 to 2 days before) can top off glycogen stores and improve performance by 2 to 3%. For shorter sessions, your normal diet provides enough glycogen.

Can I survive on zero carbs?

Technically yes, the body can produce glucose from protein and fat via gluconeogenesis. But zero-carb diets eliminate fibre, most vitamins from fruits and vegetables, and make intense exercise very difficult. Some carbohydrates are recommended for optimal health.

Results are for general informational purposes only and should be checked before use. They are not professional advice. See our Disclaimer and Terms of Service.