What is a fat intake calculator?
A fat intake calculator converts your TDEE and goal into a precise daily fat target in grams. Because fat contains 9 kcal/g — more than double the 4 kcal/g in protein or carbohydrates — small changes in fat percentage translate to large calorie shifts. The calculator takes the guesswork out by computing your BMR, activity-adjusted TDEE, and goal-specific fat range in one step.
When you enter your body fat percentage, the calculator switches from Mifflin-St Jeor to the Katch-McArdle BMR formula — which accounts for lean body mass directly and is more accurate for trained individuals.
Daily fat intake by goal
Fat targets differ by goal because each goal changes your total calorie intake, and fat percentage is applied to that new total. Example values for a 30-year-old male, 80 kg, 178 cm, moderately active (TDEE ≈ 2,650 kcal):
| Goal | Calories | Fat % range | Fat grams/day | Sat fat cap |
|---|---|---|---|---|
| Maintain weight | 2,650 | 20–35% | 59–103 g | < 29 g |
| Lose 0.5 kg/week | 2,400 | 20–35% | 53–93 g | < 27 g |
| Lose 1 kg/week | 2,150 | 20–35% | 48–84 g | < 24 g |
| Gain 0.5 kg/week | 2,900 | 20–35% | 64–113 g | < 32 g |
| Gain 1 kg/week | 3,150 | 20–35% | 70–122 g | < 35 g |
| Keto | 2,650 | 70–75% | 206–221 g | — |
Example only. Use the calculator above for your personal targets.
Fat types: what to eat, what to limit
| Fat type | Sources | Guidance |
|---|---|---|
| Monounsaturated | Olive oil, avocado, almonds, cashews | Prioritise — supports heart health and hormone production |
| Omega-3 polyunsaturated | Oily fish, flaxseed, walnuts, chia seeds | Prioritise — reduces inflammation, supports brain function |
| Omega-6 polyunsaturated | Sunflower oil, corn oil, soybean oil | Moderate — healthy in balance with omega-3s |
| Saturated | Meat, dairy, butter, coconut oil, palm oil | Limit to <10% of calories (DGA) or <7% (AHA) |
| Trans (industrial) | Partially hydrogenated oils, some margarines | Eliminate — raises LDL, lowers HDL, no safe intake level |
How the fat intake calculation works
- BMR — Mifflin-St Jeor by default; Katch-McArdle when body fat % is entered (uses lean body mass for higher accuracy).
- TDEE — BMR × activity multiplier (1.2 sedentary → 1.9 very active).
- Daily calories — TDEE ± goal adjustment (−500 kcal to lose 1 kg/week, +500 to gain 1 kg/week, 70–75% fat for keto).
- Fat in grams — (daily calories × fat %) ÷ 9 kcal/g. The range uses 20–35% for standard goals, 70–75% for keto.
- Saturated fat caps — 10% of calories (DGA) and 7% (AHA heart-health), both converted to grams.
Frequently asked questions
How much fat should I eat per day?
The Dietary Guidelines for Americans recommend 20–35% of daily calories from fat. For a 2,000 kcal diet that is 44–78 g/day. Your exact target depends on your TDEE and goal — use the calculator above for a personalised number.
How much fat per day for weight loss?
Keep fat at 20–35% of your reduced calorie target. A 500 kcal deficit on a 2,500 kcal TDEE gives 2,000 kcal/day, putting fat at 44–78 g/day. Never drop below 20% of calories as fat — this impairs hormones and vitamin absorption.
How much fat per day on keto?
On keto, 70–75% of calories come from fat. For 2,000 kcal/day that is 156–167 g of fat. Net carbs are kept under 20–50 g/day to maintain ketosis. Fat literally replaces carbohydrates as your primary energy source.
How much saturated fat per day is safe?
The DGA caps saturated fat at 10% of total calories (under 22 g on 2,000 kcal). The AHA recommends a more aggressive 7% limit for heart health (under 16 g on 2,000 kcal). Saturated fat primarily comes from meat, dairy, butter, and coconut oil.
What is the minimum fat intake per day?
The minimum safe fat intake is approximately 0.3–0.5 g/kg bodyweight per day, or 15–20% of total calories. Below this threshold, hormone production drops, fat-soluble vitamins (A, D, E, K) cannot be properly absorbed, and essential fatty acid deficiency can develop.