How many grams of protein per kg for bodybuilding?

For natural lifters, 1.6–2.2 g of protein per kg of bodyweight per day is enough for muscle growth. This calculator uses 1.8–2.4 g/kg depending on your goal and experience level.

Should I use different macros on training and rest days?

You can keep macros the same every day or use carb cycling. Many bodybuilders prefer higher carbs on training days and slightly lower carbs and calories on rest days while keeping protein high. This calculator can generate both versions.

How often should I change my bodybuilding macros?

Reassess every 2–4 weeks. If you are cutting and losing more than 1% of bodyweight per week, increase calories slightly. If you are bulking and gaining more than 0.5–1% per month, reduce calories. Adjust in 100–200 kcal steps.

Are these bodybuilding macros suitable for women?

Yes. The calculator adjusts calories for sex, body size and activity level. Protein per kg is similar for men and women, but total calories and carbs will differ based on your inputs.

Bodybuilding Macro Calculator – Custom Bulking, Cutting & Recomp Macros

How this bodybuilding macro calculator works

This bodybuilding macro calculator is designed specifically for lifters who want practical, gym-focused numbers – not generic diet advice. It combines a modern energy expenditure formula with evidence-based protein, fat and carb ranges used in bodybuilding prep, lean bulks and recomposition phases.

1. Step 1 – Estimate your maintenance calories (TDEE)

First we estimate your Basal Metabolic Rate (BMR) using the Mifflin–St Jeor equation, which is widely considered one of the most accurate for active adults:

For men:

\(\text{BMR} = 10 \times \text{weight (kg)} + 6.25 \times \text{height (cm)} - 5 \times \text{age} + 5\)

For women:

\(\text{BMR} = 10 \times \text{weight (kg)} + 6.25 \times \text{height (cm)} - 5 \times \text{age} - 161\)

Then we multiply BMR by an activity factor based on your selection:

Sedentary: × 1.2
Lightly active: × 1.375
Moderately active: × 1.55
Very active: × 1.725

This gives your TDEE – the calories you’d need to maintain your current weight if your training and activity stayed the same.

2. Step 2 – Apply a bodybuilding-specific calorie surplus or deficit

Unlike generic macro tools, this calculator uses goal- and experience-based calorie adjustments that reflect realistic muscle gain and fat loss rates for natural lifters:

Cutting: about –15% to –22% below TDEE (smaller deficit for advanced lifters).
Recomposition: around –5% to –10% below TDEE, prioritizing strength and muscle retention.
Lean bulk: about +5% to +12% above TDEE (smaller surplus for advanced lifters to limit fat gain).

The calculator automatically chooses a value in these ranges based on your training experience.

3. Step 3 – Set protein for muscle gain and retention

Protein is based on your lean body mass if you provide body fat %, or on total bodyweight if you don’t. Typical bodybuilding ranges are:

Cutting: 2.2–2.4 g/kg of bodyweight (or lean mass).
Recomp: 2.0–2.2 g/kg.
Lean bulk: 1.8–2.0 g/kg.

The calculator picks a value within these ranges depending on your goal and experience level, then converts it to calories:

\(\text{Protein calories} = \text{Protein grams} \times 4\)

4. Step 4 – Set minimum fats for hormones and health

Dietary fat is essential for hormone production and joint health. We set a minimum of about 0.6–0.8 g/kg of bodyweight, then adjust slightly based on your fat preference:

Balanced: ~0.8 g/kg.
Higher fat: ~1.0 g/kg (slightly fewer carbs).
Lower fat: ~0.6–0.7 g/kg (more carbs).

\(\text{Fat calories} = \text{Fat grams} \times 9\)

5. Step 5 – Fill the rest with carbs for performance

Whatever calories remain after protein and fat are assigned to carbohydrates, which are your primary fuel for heavy lifting and high-volume training:

\(\text{Carb calories} = \text{Target calories} - (\text{Protein calories} + \text{Fat calories})\)

\(\text{Carb grams} = \dfrac{\text{Carb calories}}{4}\)

This typically lands you in the range of 3–7 g/kg of carbs depending on your goal, activity and fat preference.

6. Optional – Carb cycling for training vs rest days

If you enable carb cycling, the calculator keeps your weekly calories similar but shifts carbs:

Training days: +10–15% calories from extra carbs.
Rest days: –10–15% calories, mostly from carbs.

Protein stays the same every day. Fats are adjusted slightly to keep calories realistic and easy to implement.

Interpreting your bodybuilding macros

The output table shows grams and percentages for each macro. For most bodybuilders:

Protein: 25–35% of calories.
Fat: 20–30% of calories.
Carbs: 35–55% of calories (often higher on training days).

Recommended weekly rate of change

Cutting: aim to lose about 0.5–1.0% of bodyweight per week.
Recomp: bodyweight may stay similar while strength and measurements improve.
Lean bulk: aim to gain about 0.25–0.5% of bodyweight per month.

If your rate is faster or slower than this, adjust calories by about 100–200 kcal and reassess after another 1–2 weeks.

Common bodybuilding macro mistakes

Going too aggressive on a cut: huge deficits kill performance and muscle. Start with a moderate deficit.
Bulking too fast: if you gain weight quickly, most of it is fat. Use a small surplus and be patient.
Underestimating protein: especially when cutting. Keep protein high to protect muscle.
Ignoring consistency: macros only work if you’re close to your targets most days of the week.

FAQ

Do I need to hit my macros exactly?

No. Think in terms of a range. Being within ±5–10 g for protein and carbs and ±3–5 g for fats is usually good enough. Over a week, consistency matters more than perfection on a single day.

Should I adjust macros on non-lifting cardio days?

For light to moderate cardio, you can usually keep the same macros as your rest days. For very intense or long-duration cardio, you may benefit from slightly higher carbs on those days.

Can I use this calculator for contest prep?

It can provide a solid starting point, but contest prep often requires more frequent and aggressive adjustments, plus individual considerations like peak week strategies. Work with a qualified coach if you’re preparing for a show.

Is this bodybuilding macro calculator suitable for keto?

No. This tool is optimized for carb-based bodybuilding diets where carbs fuel performance. For strict ketogenic approaches, you’d use much lower carbs and higher fats than the ranges used here.

Bodybuilding Macro Calculator