Keto Macro Calculator
Step 1 — Basal Metabolic Rate (BMR)
Mifflin-St Jeor: kcal/dayStep 2 — Total Daily Energy Expenditure (TDEE)
BMR × activity = kcal/dayStep 3 — Calorie target for your goal
TDEE + goal adjustment = kcal/dayWhat this means
Estimate only. Not medical advice. Talk to a doctor before starting keto, especially with diabetes, kidney issues, pregnancy, or if you take medication.
Your keto macros are the daily amounts of fat, protein, and net carbs that keep your body in ketosis. This keto calculator works them out from your age, height, weight, activity level, and goal using the Mifflin-St Jeor formula. Most people land near 20 to 30 grams of net carbs, moderate to high protein, and the rest of their calories from fat. Enter your details and press Calculate to get your targets in grams rather than percentages you have to convert yourself.
What Are Keto Macros?
Keto macros are the three numbers that run a ketogenic diet: fat, protein, and carbohydrates, measured in grams per day. Keto flips a normal diet. Instead of carbs doing most of the work, fat becomes your main fuel. That means high fat, enough protein to hold onto muscle, and very few carbs.
The classic starting split people quote is roughly 70 to 75 percent fat, 20 to 25 percent protein, and 5 to 10 percent carbs. In grams that usually works out to 20 to 50 grams of net carbs a day, protein set by your body weight, and fat filling whatever calories are left.
Here is the part most charts skip. Percentages alone are a bad target. Two people eating “75 percent fat” can need completely different gram amounts because their calories, weight, and goals differ. Our carb calculator and keto tool both work in grams for that reason. Grams are what you actually eat and track, so grams are what the calculator gives you.
Why Do Macros Matter So Much on Keto?
On keto the margin for error is small. Eat too many carbs and you drop out of ketosis. Eat too little protein and you lose muscle along with fat. Eat too much fat and weight loss stalls because your body burns the fat on your plate instead of the fat on your body.
Set your macros correctly and you stay in ketosis while holding onto lean muscle, which is what keeps fat loss from stalling. That is the whole case for calculating your numbers instead of guessing them.
How Do I Calculate My Macros for Keto?
You calculate keto macros in five steps: find your BMR, adjust for activity, set calories for your goal, split those calories into fat, protein, and carbs, then convert each split into grams. The calculator above runs all five, and here is what it does at each step so you can check the logic.
Step 1: Find Your BMR
BMR is your basal metabolic rate, the calories you burn at rest. This tool uses the Mifflin-St Jeor equation, first published in 1990 and still the formula most dietitians rely on. It takes your age, gender, height, and weight. A 30-year-old man at 5’10” and 165 lb has a BMR near 1,715 calories. That is the baseline before you move at all.
Step 2: Adjust for Activity
Next you multiply BMR by an activity factor to get your TDEE, the total calories you burn in a day. The factors range from 1.2 for sedentary up to 1.9 for very active. That same 1,715 BMR at a light activity level (1.375) becomes a TDEE of about 2,358 calories.
Step 3: Set Calories for Your Goal
Now adjust calories for what you want:
- Fat loss: subtract 250 to 500 calories for a deficit
- Maintenance: eat at your TDEE
- Muscle gain: add a small surplus of around 250 calories
Calories still count on keto. A 500-calorie deficit takes that 2,358 TDEE down to about 1,858 calories per day for fat loss.
Step 4: Split the Calories
The calculator sets your net carbs from the target you choose (default 25 grams), sets protein from your body weight to protect muscle, then fills the rest with fat. This is where the tool differs from a plain percentage chart. Because protein is tied to your body, not to a flat 20 percent, your protein often lands a little higher than the old-school ratios suggest. That is intentional, because protein needs scale with body size rather than with total calories.
Step 5: Convert to Grams
Calories become grams using simple conversions:
- Carbs: 4 calories per gram
- Protein: 4 calories per gram
- Fat: 9 calories per gram
For that 1,858-calorie fat-loss example the result is about 135 g protein, 135 g fat, and 25 g net carbs, which comes out near 29 percent protein, 66 percent fat, and 5 percent carbs. Those are your daily keto targets.
How Many Carbs Per Day on Keto? (Men vs Women)
Most people need 20 to 30 grams of net carbs per day to stay in ketosis. Some can go up to 50 grams and stay in. For steady fat loss, 20 to 30 grams is the reliable range.
Standard Keto Carb Limits
- Strict keto: 20 g net carbs
- Standard keto: 20 to 30 g net carbs
- Liberal keto: up to 50 g net carbs
If your goal is weight loss, staying nearer 20 to 25 grams usually works best.
Do Men and Women Need Different Carbs?
Slightly, but not dramatically. Men tend to carry more muscle and burn more calories, so they can sometimes handle a few more carbs. Women often have lower total calorie needs and may enter ketosis at a slightly lower carb level.
The bigger drivers are not gender at all. Body size, activity level, insulin sensitivity, and overall metabolic health decide your real carb tolerance far more than male versus female does.
A practical starting point: a lightly active 150 lb woman aiming for fat loss does well at 20 to 25 g net carbs, while a moderately active 200 lb man targeting fat loss can often sit at 25 to 35 g. Both should adjust after two to three weeks based on results and ketone readings.
Net Carbs vs Total Carbs
On keto you count net carbs, not total carbs. Net carbs are what actually raise blood sugar and threaten ketosis. Fiber and most sugar alcohols pass through with little blood sugar impact, so you subtract them. More on the exact formula next.
How to Calculate Net Carbs for Keto
Net carbs equal total carbs minus fiber minus sugar alcohols. That single formula decides whether a food fits your daily limit, so it is worth getting right.
Net Carbs = Total Carbs − Fiber − Sugar Alcohols
Worked Net Carb Examples
From a food label showing 15 g total carbs, 8 g fiber, and 3 g sugar alcohols:
15 − 8 − 3 = 4 g net carbs
That food only spends 4 grams of your daily budget, not 15. A few more real foods:
| Food (1 serving) | Total Carbs | Fiber | Net Carbs |
|---|---|---|---|
| Avocado (1 medium) | 12 g | 9 g | 3 g |
| Almonds (1 oz) | 6 g | 3 g | 3 g |
| Broccoli (1 cup) | 6 g | 2 g | 4 g |
| Cauliflower (1 cup) | 5 g | 2 g | 3 g |
A Note on Sugar Alcohols
Not all sugar alcohols behave the same. Erythritol is usually subtracted in full because it barely affects blood sugar. Maltitol is different and can raise it. To stay safe, subtract all fiber, all erythritol, and only half of other sugar alcohols. That keeps your carb count honest and keeps you in ketosis.
Keto Macros for Weight Loss
Keto helps with fat loss, but keto by itself does not guarantee it. Weight loss happens when your keto macros create a calorie deficit while carbs stay low enough for ketosis. Get both right and the fat comes off steadily.
Calories Still Decide Fat Loss
Keto makes dieting easier by cutting hunger and steadying blood sugar, but the deficit is what moves the scale. If calories creep too high, even from “keto-friendly” fats, progress slows. The calculator sizes your deficit from your weight, activity, and goal so you are not guessing. You can cross-check your baseline with a dedicated calorie calculator if you want a second number.
Set Protein High Enough
Protein protects muscle during a deficit. Too little and you lose lean tissue, slow your metabolism, and recover poorly. This tool bases protein on your body weight rather than a flat percentage, which is why keto dieters chasing fat loss usually see protein land in the higher end of the range. If you want to dig into protein targets on their own, a focused protein calculator breaks it down further.
Let Fat Fill the Rest
Keto is high fat, but fat is not unlimited. Once carbs and protein are locked, fat fills whatever calories remain. If weight loss stalls, trimming fat slightly is usually what restarts it, since fat carries 9 calories per gram and adds up fast. A fat intake calculator can help you see how small fat changes shift your totals.
Worked Example: Fat Loss Macros
A 35-year-old man, 5’10”, 200 lb, moderately active, aiming for fat loss at 25 g carbs lands near:
- Calories: about 2,365 per day
- Protein: 163 g (28 percent)
- Fat: 179 g (68 percent)
- Net carbs: 25 g (4 percent)
A 30-year-old woman, 5’4″, 150 lb, lightly active, fat loss at 20 g carbs lands near 1,405 calories, 122 g protein, 93 g fat, and 20 g net carbs.
Common Weight Loss Mistakes on Keto
- Eating fat bombs daily and ignoring total calories
- Setting protein too low and losing muscle
- Counting total carbs instead of net carbs
- Never adjusting after the first few weeks
Why Accurate Keto Macros Matter
On keto, small errors have big effects. Being off by 10 to 20 grams of carbs can push you out of ketosis. Being off on protein can cost you muscle. Being off on fat can stall the scale for weeks.
Accurate macros keep you under your own carb threshold, set protein from your body composition instead of a flat percentage, and leave fat at a level that still lets you burn stored fat. Copying someone else’s numbers skips all of that, which is why two people on keto can need very different targets.
Macros set from your own numbers make keto easier to stick with, because hunger drops and your progress follows a pattern you can read.
Keto vs Low Carb: What Is the Difference?
People mix these up, but they are not the same. Keto is a stricter, lower-carb version built specifically to reach ketosis. Low carb just means fewer carbs than a standard diet, without the strict ratios.
| Feature | Keto | Low Carb |
|---|---|---|
| Carb intake | 20 to 50 g net carbs/day | Usually 50 to 150 g/day |
| Fat intake | High (roughly 70 percent of calories) | Moderate to high |
| Protein intake | Moderate to high | Can be higher |
| Main goal | Reach ketosis | Reduce carbs for weight or health |
| Fuel source | Fat and ketones | Mostly glucose |
Keto usually drives faster early fat loss thanks to ketosis and appetite suppression. Low carb is more flexible and easier to keep up long term. Pick keto if you want faster fat loss or blood sugar control. Pick low carb if you want a simpler plan you can stick to for years.
Frequently Asked Questions
How much weight will I lose on keto?
It depends on your calorie deficit, activity, and how tightly you hold your macros. Water weight usually drops fast in the first week, after which fat loss settles into 1 to 2 pounds per week. Setting your calories and macros with the calculator keeps that loss steady without sacrificing muscle.
How many carbs per day should a woman eat on keto?
Start at 20 to 25 grams of net carbs per day and treat that as a test, not a rule. Body size, training load, and insulin sensitivity move the real limit more than gender does. Larger or very active women may handle a little more. Track net carbs, not total, and adjust after a couple of weeks based on results.
What should my keto macro percentages be?
Percentages are a starting frame, not a target. Once protein is set from your body weight it usually lands above the 20 to 25 percent figure people quote, with fat taking whatever calories are left. In practice, when protein is set from your body weight, it often lands a bit higher and fat a bit lower. That is normal and better for holding muscle. Gram targets matter more than hitting exact percentages.
How do I calculate net carbs?
Subtract fiber and sugar alcohols from total carbs. Only that remainder counts toward your daily keto limit, which is why a high-fiber food can fit a 20 g budget. The worked example above shows the arithmetic on a real label.
Do calories still matter on keto?
Yes. Switching fuel sources does not remove the need for a deficit. Fat bombs and heavy cream are the usual places keto calories creep back up.