Carbohydrate Calculator

What this carbohydrate calculator does

Carbohydrates are a major energy source. This calculator estimates the grams of carbohydrate that fit different calorie targets and different shares of daily calories: 40%, 55%, 65%, and 75%.

The ranges are planning guides. The right amount depends on activity, food preferences, blood glucose, and medical conditions.

How to use this calculator

1. Enter age, sex, height, and weight.
2. Choose a BMR formula and activity level.
3. Click Calculate to see carbohydrate targets for maintenance, weight loss, and weight gain.

The default example is a 25-year-old man who is 5 ft 10 in and weighs 160 lb with a light activity level.

Carbohydrate formulas

Maintenance calories = BMR × activity multiplier
Loss 1 lb/week = maintenance − 500
Loss 2 lb/week = maintenance − 1,000
Gain 1 lb/week = maintenance + 500
Gain 2 lb/week = maintenance + 1,000
Carbohydrate grams = calories × percentage ÷ 4

What the results mean

The table shows a calorie target for each goal and four carbohydrate amounts. A 55% share is a common moderate-carbohydrate starting point; 40% is lower and 65–75% is higher.

For the default example, maintenance is about 2,361 calories. At 55%, that is about 325 g of carbohydrate per day.

Assumptions and limitations

The calculator does not include fiber, sugar, or food quality. It does not account for diabetes, insulin resistance, kidney disease, or individual tolerance. Very low carbohydrate intake can be appropriate for some people and inappropriate for others.

Carbohydrate needs are not a substitute for medical nutrition therapy. Discuss major changes with a clinician or registered dietitian.

Frequently asked questions

How many carbohydrates do I need?

There is no single requirement. The Dietary Guidelines emphasize nutrient-dense carbohydrate foods, including whole grains, fruits, vegetables, and legumes.

Is a low-carb diet better?

It can be helpful for some people and unnecessary for others. Total energy balance and food quality matter; the best approach depends on health and sustainability.

Why is carbohydrate 4 calories per gram?

Carbohydrate provides about 4 kcal per gram, similar to protein. Fat provides about 9 kcal per gram.

Does this include fiber?

No. Fiber is a carbohydrate, but it is not separated here. Aim for fiber-rich foods rather than only counting grams.

Source

References:

• Dietary Guidelines for Americans
• NIDDK — Body Weight Planner

Disclaimer

This calculator is for informational and educational purposes only. It is not medical advice or a personalized meal plan. Consult a registered dietitian or clinician for individual guidance.