Starting keto, or not losing on it? Your macros are the first thing to check. Enter your details below and this free calculator works out your daily calories and your keto split: how many grams of fat, protein and carbs to aim for each day, matched to whether you want to lose, maintain or gain.
Keto Macro Calculator
Work out your daily calories and keto macros, fat, protein and carbs, from your body and your goal.
Uses the Mifflin-St Jeor equation with a classic keto split (70% fat, 25% protein, 5% carbs). Most people on keto keep carbs at or under about 50 g a day regardless of calories. These are estimates to plan with, not medical advice. Check with your doctor before big diet changes, especially if you take medication.
How Your Keto Macros Are Calculated
The calculator uses the Mifflin-St Jeor equation, the standard formula dietitians use, to estimate how many calories your body burns at rest from your sex, age, weight and height. It then adjusts for your activity level to find your maintenance calories: roughly what you burn in a normal day. Finally it applies your goal. Losing uses a 20% reduction, which is a steady, sustainable pace for most people; gaining adds 10%.
Your calories are then split the classic keto way: 70% fat, 25% protein, 5% carbs. That low carb share is what keeps your body in ketosis. In practice, most people on keto also cap carbs at around 20–50 grams a day whatever the percentage says, especially when starting out.
How to Use Your Numbers
Carbs are a limit. Stay at or under your carb grams to stay in ketosis. Fibre does not count toward the limit in the way sugar and starch do, which is why keto counts net carbs on most foods.
Protein is a target. Try to reach your protein grams most days. Too little and you lose muscle along with fat; wildly too much is unnecessary for most people, despite what you may read.
Fat is a lever, not a goal. Eat fat to feel full, but you do not have to force yourself to hit the full fat number every day, especially if weight loss is the goal. If you are full at less, that is fine.
Recalculate whenever your weight changes by about 5 kg (10 lb), because your targets shrink as you do. Planning your shopping around your numbers is easier with our perfect keto grocery list, and if you are wondering about specific foods, see can you eat carrots on keto? and our honest guide to whether keto gummies really work.
A Quick Word of Caution
These numbers are estimates, good ones, but no formula knows your body exactly. Treat them as a starting point and adjust by what actually happens over two to three weeks. If you have a medical condition, or you take medication for diabetes or blood pressure, talk to your doctor before starting keto: the diet can change how those medicines work. This calculator is a planning tool, not medical advice.
Keto Macro Calculator FAQs
What is the best macro split for keto?
The classic split is about 70% of calories from fat, 25% from protein and 5% from carbs. It works well for most beginners. What matters most is the carb limit, the fat and protein can flex a little around it.
How many carbs can I eat on keto?
Most people stay in ketosis at 20–50 grams of net carbs a day. Beginners often do best starting near 20 grams, then testing whether they can go a little higher once they are settled into the diet.
Why am I not losing weight on keto?
The usual reasons: calories quietly creeping up (fat is very calorie-dense), hidden carbs in sauces and snacks, or macros calculated for your old, higher weight. Recalculate with your current weight and track honestly for a week before changing anything else.
Do I need to hit my fat target every day?
No. Fat is there to keep you full and make meals satisfying. On a weight-loss keto plan, eating less fat than your maximum simply means more of the energy comes from body fat instead, which is the point.