Carbohydrate Calculator guide
Carbohydrate Calculator: How Many Carbs Should I Eat a Day?
Use our carbohydrate calculator to work out how many grams of carbs to eat a day based on UK guidance, plus your free sugar limit and fibre target.
By the AllCalculator editorial teamUpdated 16 October 20262 min read
Carbohydrates are the body's main source of energy, and UK guidance says they should make up about half of what you eat. Our Carbohydrate Calculator turns that into grams for you.
How to use the calculator (Carbohydrate Calculator)
- Enter your sex, age, weight and height.
- Choose your activity level and goal.
You'll see how many grams of carbohydrate to eat a day, a range, your free sugar limit and fibre target.
UK guidance on carbohydrates
In 2015, the Scientific Advisory Committee on Nutrition (SACN) recommended that:
- About 50% of your energy should come from carbohydrate, mostly starchy, high-fibre foods.
- Free sugars should be no more than 5% of your energy. That's about 30g a day for adults.
- Adults should eat 30g of fibre a day.
Free sugars are sugars added to food and drink, plus those in honey, syrups and fruit juice. The sugar in whole fruit, vegetables and milk doesn't count.
How it works
The calculator works out your daily calories, then:
Carbs in grams = calories × 50% ÷ 4
because each gram of carbohydrate has about 4 kcal.
A worked example
With the calculator's default settings, daily calories are about 1,940 kcal, so 50% from carbohydrate is about 243g a day, with a range of 219g to 267g.
Good sources of carbohydrate
- Wholegrain bread, pasta and rice
- Oats and wholegrain breakfast cereals
- Potatoes with their skins on
- Beans, lentils and chickpeas
- Fruit and vegetables
Frequently asked questions
Are carbs bad for weight loss?
No. Weight loss comes from eating fewer calories than you use, whatever their source. High-fibre carbs can help you feel full.
What about low-carb diets?
Some people find them easier to follow. If you have diabetes, speak to your diabetes team before changing how many carbs you eat.
How do I check carbs on labels?
Look for "Carbohydrate" and "of which sugars" on the nutrition label, per 100g or per portion.
To split all your calories into carbs, protein and fat, use our Macro Calculator.
Sources and further reading
- GOV.UK: SACN carbohydrates and health reportgov.uk
- NHS: The Eatwell Guidenhs.uk
- NHS: Starchy foods and carbohydratesnhs.uk
Links open official and independent websites in a new tab.
This guide is general information to help you understand your options. It isn't financial, tax, legal or building advice and doesn't take your personal circumstances into account. Figures were checked when the guide was last updated and can change, so confirm anything important with GOV.UK, HMRC, a regulated adviser or a qualified tradesperson.