Carbohydrate Intake Calculator
Turn your daily calorie target into grams of carbohydrate for your goal — from keto to high-carb — with a fibre target.
For most healthy adults, carbohydrate provides 45–65% of total calories — roughly 225–325 g per day at 2,000 kcal — with lower-carb and keto plans deliberately below that band.
How to work out your carbs
Carbohydrate is measured as a share of your total calories. Each gram supplies about 4 calories, so once you pick a percentage for your goal, the grams follow: calories × carb% ÷ 100 ÷ 4. For general health, guidelines put carbohydrate at 45–65% of calories (the AMDR); lower-carb and keto approaches sit deliberately below that band. Start from a calorie number that fits your goal — the TDEE calculator estimates it — then choose a split here.
Carbohydrate is one piece of the puzzle: the macro calculator splits your whole intake into protein, carbs and fat together. This tool focuses on carbs and adds a fibre target, because quality matters as much as quantity.
Quality over quantity
Where your carbs come from matters more than the exact gram count. Aim to get most from fibre-rich whole foods — whole grains, legumes, fruit and vegetables — and keep free and added sugars under about 10% of calories, as the WHO recommends. A useful fibre goal is 14 g per 1,000 calories. Endurance athletes are usually better served by grams-per-kilogram targets than by a percentage of calories.
Carb targets by goal (at 2,000 kcal)
| Goal / diet type | Carb % of calories | Grams at 2,000 kcal |
|---|---|---|
| Ketogenic (very low carb) | 5–10% | 25–50 g |
| Low-carb | 10–25% | 50–125 g |
| Moderate (below AMDR floor) | 40–44% | 200–220 g |
| Balanced | 45–55% | 225–275 g |
| Higher-carb / endurance | 55–65% | 275–325 g |
| Carb RDA (minimum) | — | 130 g |
| Fibre target | — | ~28 g |
Carbs (g) = calories × carb% ÷ 4. The healthy-adult AMDR is 45–65% of calories; 130 g/day is the RDA minimum for brain glucose; fibre ≈ 14 g per 1,000 kcal.
Sources: IOM/NASEM Dietary Reference Intakes (AMDR, RDA, fibre); ISSN/ACSM athlete guidance; WHO free-sugars guideline. General information, not medical advice.
Frequently asked questions
How many carbs should I eat per day?
It depends on your calorie needs and goals. Within the general healthy-adult range (the AMDR), carbohydrate provides 45–65% of total calories — about 225–325 g/day at 2,000 kcal. Enter your own calorie target and pick a goal band to see your number. The tool assumes 4 kcal per gram of carbohydrate.
How is the carb gram number calculated?
Carbs (g) = daily calories × carb% ÷ 100, divided by 4. The 4 is the Atwater factor: each gram of carbohydrate supplies about 4 kcal. So at 2,000 kcal and 50%, that is 2,000 × 0.50 = 1,000 carb kcal, then 1,000 ÷ 4 = 250 g.
What counts as low-carb versus keto?
There's no single legal definition, but research commonly treats 'low-carb' as roughly 10–25% of calories (often under 130 g/day) and 'ketogenic' as about 5–10% of calories and, in practice, under 50 g of total carbohydrate per day (sometimes under 20–25 g during an induction phase). This tool caps the keto band at 50 g/day.
How much fibre should come with those carbs?
A common target is 14 g of fibre per 1,000 calories, which works out to roughly 25 g/day for many women and 38 g/day for many men. Aim to get most carbohydrate from fibre-rich whole foods — whole grains, legumes, fruit and vegetables — and keep free/added sugars under about 10% of calories, per the WHO.
I'm an athlete — is % of calories the right way to set carbs?
Often not. Sports-nutrition bodies (ISSN, ACSM) recommend setting carbohydrate by body weight rather than percentage: about 3–5 g/kg for light training, 5–7 g/kg for around an hour a day, 6–10 g/kg for 1–3 hours of endurance work, and 8–12 g/kg for very high volumes. Use a gram-per-kg target if you train hard, then check it against your calorie total.
Sources
- Institute of Medicine — Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Protein (2005) — RDA 130 g/day; AMDR 45-65% energy
- MedlinePlus (NIH/NLM) — Carbohydrates — 45-65% of daily calories from carbs
- WHO — Carbohydrate intake for adults and children (2023) — Carbohydrate intake and quality guidance
The thresholds and formulas used by this calculator follow the primary sources above. This tool provides general information, not personalised medical advice.