Carbohydrate Calculator
A carbohydrate calculator helps you estimate daily carbohydrate needs and manage your carb intake. Carbohydrates are a primary energy source for the body alongside protein and fat, and the right amount depends on personal factors such as age, weight, height, activity level and your target (for example weight loss, maintenance or performance).
Use the calculator to get an evidence-based estimate of grams of carbohydrate per day and suggested distribution throughout day — enter your age, weight, activity level and target to see personalised results. For example, a recreational runner will usually need more carbs than a sedentary office worker to fuel activity and support recovery.
Types of carbohydrate
Carbohydrates are commonly grouped into three types according to their chemical structure and how the body handles them:
- Simple carbohydrates: also called sugars, these are monosaccharides and disaccharides (one or two sugar molecules). They are rapidly digested and can provide quick energy. Typical examples are glucose, fructose (fruit) and lactose (milk). Common foods: a small can of sugary drink (~35 g carbs), a medium banana (~27 g carbs).
- Complex carbohydrates: polysaccharides made of longer sugar chains that take longer to digest and release energy more steadily. Foods rich in complex carbs include whole grains (oatmeal, brown rice), legumes and starchy vegetables (potato, sweet potato). Typical portions: one medium potato ≈ 30–35 g carbs; 1 cup cooked brown rice ≈ 45 g carbs.
- Fibre: a carbohydrate the body largely cannot digest. Fibre comes in soluble and insoluble forms — soluble fibre can help slow glucose absorption and support stable blood sugar, while insoluble fibre aids regular bowel movements. High-fibre foods include vegetables, fruits, whole grains, nuts and seeds (for example, 1 slice wholemeal bread ≈ 12–15 g carbs with 2–3 g fibre).
Practical note: when calculating carbohydrate needs, consider both total grams of carbs and the type — favouring complex carbs and higher-fibre foods helps steady energy and supports overall health. Use the calculator to translate your recommended carbohydrate grams into everyday food equivalents so you can plan meals throughout the day.
Good Carbs vs Bad Carbs
Nutritionists often distinguish between carbohydrates to favour or to limit based on nutrient quality and how they affect blood sugar. The terms “good” and “bad” are useful shorthand but remember that total carbohydrate intake and calories also determine weight and health outcomes.
Good carbs (favour)
Complex carbs and higher‑fibre foods are generally the best choice for most people. Because they digest more slowly, complex carbs provide a steadier release of energy and help maintain stable blood sugar. Examples include whole grains (whole wheat, quinoa, brown rice), legumes, starchy vegetables and most fruits. These foods also supply fibre, vitamins and minerals — fibre helps you feel full, supports gut health and can moderate post‑meal blood sugar levels.
Practical guidance: if your calculator suggests, for example, 200–300 g carbs per day (depending on activity and target), split this across 3–5 meals — roughly 40–80 g per meal and smaller amounts for snacks. Translate grams into foods: 1 cup cooked brown rice ≈ 45 g carbs, 1 medium potato ≈ 30–35 g, one slice wholemeal bread ≈ 12–15 g.
Carbs to limit (moderate)
Rapidly digested simple carbs — found in sugary drinks, sweets, pastries and many ultra‑processed snacks — can cause quicker rises and falls in blood sugar and may contribute to excess calorie intake and weight gain if consumed in large amounts. These foods are typically low in fibre and other nutrients, so treat them as occasional choices rather than staples.
When higher‑glycaemic carbs are useful: simple carbs are appropriate around intense training or competition to provide quick energy or to replenish muscle glycogen after prolonged exercise. For people aiming to build muscle or support heavy training, overall carbohydrate intake will be higher and tailored to activity level and fitness goals.
How this ties to the calculator: the tool estimates daily carbohydrate intake based on your age, weight, height, activity level and target (lose, maintain, gain). It then converts those grams into practical food examples and a suggested distribution throughout the day so you can meet energy needs for everyday life, fitness or muscle growth while managing calorie balance.
Final note: consider both quality and amount — favour whole grains, vegetables and fibre‑rich foods most of the time, limit added sugars and highly processed foods, and adjust carbohydrate intake to your activity and weight goals. If you have diabetes or other health conditions affecting blood sugar, follow medical advice and discuss carbohydrate targets with a registered dietitian.
Disclaimer: The carbohydrate calculator on this page is for informational purposes only and is not a substitute for personalised advice from a qualified healthcare professional or registered dietitian. The calculator provides estimated results based on general recommendations and may not be appropriate for everyone — individual carbohydrate needs vary according to age, weight, height, activity level, medical conditions, medications and personal targets (for example weight loss, maintenance or muscle gain).
Use the calculator to get an initial estimate of daily grams of carbohydrate and suggested distribution throughout day; the results include practical food equivalents and a recommended split across meals and snacks to help manage calorie and carbohydrate intake. If you have diabetes, blood‑sugar concerns, heart disease or other health conditions, or if you take medication that affects blood sugar or appetite, follow your clinician’s guidance and discuss any changes with a specialist before altering your diet or exercise routine.
If you would like tailored recommendations, consider booking a consultation with a registered dietitian or qualified nutrition professional who can interpret your results, adjust carbohydrate intake for your needs and fitness goals, and help you plan meals that support health, performance and weight management.
