Know your exact macros — before you start keto
Keto is more than "eat less carbs." Fat must become your primary fuel source, protein needs to be carefully moderated, and carbs must stay low enough to trigger and sustain ketosis. This calculator gives you precise, personalized numbers — not generic ratios — so you actually hit ketosis and stay there.
What Is a Keto Calculator?
A keto calculator computes your personalized fat, protein, and net carb targets for a ketogenic diet. Unlike a standard macro calculator, a keto calculator accounts for the specific macro ratios needed to enter and maintain ketosis — the metabolic state where your body burns fat for fuel instead of glucose.
This calculator uses your BMR (Basal Metabolic Rate), TDEE (Total Daily Energy Expenditure), body weight, goal, and chosen keto strictness to generate a macro plan tailored to you — not a one-size-fits-all template.
How to Use This Keto Calculator
- Choose your unit system: Metric (kg/cm) or Imperial (lbs/ft&in).
- Select biological sex: Used in the Mifflin-St Jeor BMR formula (different constants for male/female).
- Enter age, height, and weight: All three are required for accurate BMR calculation.
- Body fat % (optional): If you know it, protein targets will be based on lean body mass — more accurate for keto.
- Select activity level: Determines your TDEE multiplier. When in doubt, choose "Lightly Active" and adjust after a week.
- Choose your goal: Weight loss, maintenance, or lean muscle gain adjusts your total daily calories.
- Set keto strictness: Strict (20g), Standard (30g), or Liberal (50g) net carbs per day. Beginners usually start with Strict or Standard.
- Read your results: Calorie target, fat/protein/net carb grams, BMR/TDEE, and personalized recommendations.
How the Keto Calculator Works (Formulas)
Step 1 — BMR (Mifflin-St Jeor)
Male: BMR = (10 × kg) + (6.25 × cm) − (5 × age) + 5
Female: BMR = (10 × kg) + (6.25 × cm) − (5 × age) − 161
BMR is the calories your body burns at complete rest — just to keep organs functioning. It's the foundation of every calorie calculation.
Step 2 — TDEE (Activity Multiplier)
TDEE = BMR × Activity Factor
Activity factors: Sedentary 1.2 · Light 1.375 · Moderate 1.55 · Very Active 1.725 · Extra Active 1.9
TDEE is your total daily calorie burn including all movement and exercise.
Step 3 — Calorie Target (Goal)
Aggressive loss: TDEE × 0.75 | Loss: TDEE × 0.85 | Maintenance: TDEE × 1.0 | Gain: TDEE × 1.10
Your calorie target is adjusted from TDEE based on whether you want to lose weight, maintain, or gain lean muscle.
Step 4 — Keto Macro Split
Net Carbs: Fixed at your chosen limit (20g / 30g / 50g) → Carb calories = net carbs × 4
Protein: 1.6–1.9g per kg of (lean) body weight → capped at 35% of calories
Fat: Fills remaining calories → Fat g = remaining ÷ 9
Net Carbs vs Total Carbs on Keto — Explained
One of the most important concepts on keto is understanding net carbs. Not all carbohydrates affect blood sugar and insulin the same way.
The Formula
Net Carbs = Total Carbohydrates − Dietary Fiber − Sugar Alcohols (most types)
Why Fiber Doesn't Count
Dietary fiber passes through the digestive system largely undigested. It does not significantly raise blood glucose or trigger an insulin response, so it doesn't disrupt ketosis. Most keto approaches subtract fiber from total carbs.
Sugar Alcohols — Partial Subtraction
Common sugar alcohols like erythritol and xylitol have minimal glycemic impact and are typically fully subtracted. Others like maltitol have a higher glycemic index and may only be partially subtracted. When in doubt, subtract 50% of sugar alcohol grams.
| Food | Total Carbs | Fiber | Sugar Alcohols | Net Carbs |
|---|---|---|---|---|
| Avocado (100g) | 9g | 7g | 0g | 2g |
| Almonds (30g) | 6g | 3g | 0g | 3g |
| Broccoli (100g) | 7g | 3g | 0g | 4g |
| Keto bread (1 slice) | 14g | 8g | 2g (erythritol) | 4g |
| Banana (medium) | 27g | 3g | 0g | 24g ⚠️ |
Keto Macro Reference Table
| Keto Type | Fat | Protein | Net Carbs | Best For |
|---|---|---|---|---|
| Standard Keto (SKD) | 70–75% | 20–25% | ≤20–30g | Weight loss, general health |
| Targeted Keto (TKD) | 65–70% | 20–25% | +25g around workouts | Active gym-goers |
| Cyclical Keto (CKD) | 70% on keto days | 20–25% | 50–150g on carb days | Athletes, bodybuilders |
| High-Protein Keto | 60–65% | 30–35% | ≤30g | Muscle preservation/gain |
| Liberal Keto | 60–65% | 20–25% | ≤50g | Active individuals, maintenance |
Percentages are approximate. Individual ketosis thresholds vary. Always adjust based on real-world results and how you feel.