How the keto calculator works
- Calories: we estimate your TDEE and apply your goal (Cut −20%, Maintain, Bulk +10%).
- Net carbs: fixed at the limit you choose: 20 g (strict), 30 g or 50 g a day.
- Protein: set by bodyweight, the same as our other calculators (2.2 g/kg on a cut, 1.8 g/kg at maintenance, 1.6 g/kg on a bulk).
- Fat: whatever calories remain.
Many keto guides use fixed percentages such as 70% fat, 25% protein and 5% carbs. We set protein in grams instead, so on a cut your protein share is often higher than those templates. The methodology page lists every formula.
Net carbs vs. total carbs
Net carbs are total carbohydrates minus fiber. On U.S. nutrition labels, fiber is already included in total carbs, so subtract it. Labels in some other countries list carbohydrates without fiber, in which case the carb figure is already close to net carbs. Sugar alcohols are handled differently by different brands; when in doubt, count them.
| Net-carb limit | Who often uses it |
|---|---|
| 20 g / day | Strict keto, especially in the first weeks |
| 30 g / day | A common middle ground once adapted |
| 50 g / day | A looser, low-carb approach; some people stay in ketosis at this level, others do not |
Is protein a problem on keto?
Protein still matters on keto, particularly in a calorie deficit, where it helps you keep muscle. We keep the same grams per kilogram as on any other diet. If you are following a medically supervised ketogenic diet (for example for epilepsy), your care team will set protein, and this calculator is not the right tool.
The first weeks
Many people feel tired, foggy or headachy in the first days of keto, often called the "keto flu". Fluid and sodium losses are thought to play a part. Drinking enough water and getting enough salt and other electrolytes from food can help; if you have high blood pressure or kidney or heart conditions, ask your doctor before increasing salt. The scale often drops quickly in week one, mostly from water as glycogen stores fall.
Who should talk to a doctor first
Check with your doctor before starting keto if you:
- take medication for diabetes (including insulin or SGLT2 inhibitors) or blood pressure,
- have type 1 diabetes, kidney disease, liver or gallbladder problems, or a history of pancreatitis,
- are pregnant or breastfeeding, or have a history of disordered eating.
Keto Macro Calculator FAQ
How many carbs can I have on keto?
Most keto plans use 20–50 g of net carbs a day. Starting at 20 g makes it more likely you reach ketosis; some people can go higher once adapted.
What should my keto macros be?
Pick your net-carb limit, set protein for your bodyweight and goal, and get the rest from fat. The calculator turns that into grams.
Do I have to hit my fat target?
On a cut, fat is a ceiling rather than a goal: eating less fat simply makes the deficit larger. Hit your protein and stay under your carb limit first.
Is keto better than other diets for weight loss?
When calories and protein are matched, studies generally find similar fat loss across diets. Keto works well for people who find it easier to stick to; a regular deficit works too.
Sources
- Masood W, Annamaraju P, Khan Suheb MZ, Uppaluri KR. Ketogenic Diet. StatPearls, StatPearls Publishing.
- U.S. Food and Drug Administration. Drug safety communication on ketoacidosis with SGLT2 inhibitors, 2015.
- Jäger R, et al. International Society of Sports Nutrition position stand: protein and exercise. Journal of the ISSN, 2017.
General information only, not medical advice. Talk to a qualified healthcare professional before starting a ketogenic diet, especially if you take medication or are managing a medical condition.