Nutrition

Macro Calculator

Convert your calorie target into daily protein, carbs, and fat grams based on your goal and split preference.

For maintenance, eat 2,400 kcal/day: 144g protein (1.8g/kg), 228g carbs, and 101g fat. Spread across 3-4 meals, that's about 36g protein per meal — roughly a palm-sized portion of meat or fish plus a scoop of whey.

Daily Macro Targets

Calories

2,400 kcal

Protein

144 g

Carbs

228 g

Fat

101 g

Daily Macro Split

Protein, carbs, and fat add up to the full daily nutrition target.

Daily grams

473 g

Protein

144 g

Carbs

228 g

Fat

101 g

Track your macros accurately

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Formula: Protein from bodyweight × goal multiplier; remaining calories split by preference.

How to use it

Select your goal (cut, maintain, bulk, or a specific split like keto/high-protein) before entering body stats — the goal determines your carbohydrate and fat ratio. Protein target is held roughly constant regardless of the split.
Verify the total calorie output matches your TDEE ± your deficit or surplus. If it does not match, recheck the activity level input — this is the most common source of discrepancy.
Carbohydrate timing improves training performance: concentrate 50–60% of your daily carbs around your training window (pre- and post-workout) if you train at moderate to high intensity.
If full macro tracking feels overwhelming, start with protein only. Consistently hitting protein within 10% of target daily delivers roughly 80% of the benefit of complete macro tracking.
Check that fat grams do not fall below 0.3g per lb of body weight — this is the floor for hormonal function. If the macro split pushes fat below this, reduce carbs and raise fat accordingly.

AI Integrations

Contract, discovery endpoints, and developer notes for agent use.

Always available for agents

Tool contract JSON

https://aifithub.io/contracts/macro-calculator.json

Stable input and output contract for this exact tool.

Human review

People can use the browser page to sense-check outputs and charts, but agents should still execute against the contract and discovery endpoints.

/agent-tools.json - machine-readable tool index.
/llms.txt - human-readable model discovery guide.
/.well-known/webmcp.json - WebMCP capabilities manifest.
/.well-known/ai-plugin.json - plugin-style discovery manifest.

{
  "tool": "macros",
  "calories": 2200,
  "protein_pct": 30,
  "carbs_pct": 40,
  "fat_pct": 30
}

Open tool contract JSON Open AI integrations guide

Expand developer notes

Agent playbook

Resolve Macro Calculator from /agent-tools.json and open its contract before execution.
Validate inputs against the contract schema instead of scraping labels from the page UI.
Open the browser page only when a person wants to review charts, assumptions, or related tools.

Agent FAQ

Should ChatGPT, Claude, or another agent click through the UI?

No. Start with /agent-tools.json, then follow the tool's contract URL. The page UI is for human review, not parameter discovery.

When do tools show Quick and Advanced?

Every tool opens in Quick Start first. Advanced Controls keeps the same scenario, reveals more assumptions or diagnostics, and every tool keeps AI integrations inline below the instructions.

When should an agent still open the browser page?

Open it when a human wants to sense-check the output, review the chart, or keep exploring related tools after the calculation finishes.

Questions people usually ask

Which formula is used here?

Uses goal-adjusted calorie targets, bodyweight-based protein ranges, and selected carb/fat split assumptions.

Can I use metric or imperial units?

Yes. This tool supports both metric and imperial units and remembers your preference.

Is this medical advice?

No. This tool provides general fitness estimates and should not replace medical guidance.

Is this tool free and private to use?

Yes. AI Fit Hub tools are free, no-signup browser tools. Inputs stay in your browser unless you choose to share a URL.

Do these tools replace medical guidance?

No. These outputs are general fitness estimates — not medical advice.

Can I switch between metric and imperial units?

Yes. Every tool supports both systems and remembers your preference in localStorage.

Related Resources

Learn the decision before you act

Every link here is tied directly to Macro Calculator. Use the explanation, formula, examples, and benchmarks to pressure-test the calculator output from first principles.

Browse all 70 resources

Guides · 11 Checklists · 8 Comparisons · 5 Learn · 4 Tips · 15

How To Use

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How to Use BMR Calculator

reveal your body's baseline calorie needs with our BMR calculator. Learn to accurately input data, interpret results, and strategize weight loss, gain, or maintenance goals.

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How to Use Macro Calculator

reveal your fitness potential by mastering our Macro Calculator. Customize your protein, carb, and fat intake for weight loss, muscle gain, or maintenance. Optimize your diet today!

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How To Use

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How to Use TDEE Calculator

reveal your daily calorie needs with our TDEE Calculator guide. Learn how to accurately calculate Total Daily Energy Expenditure to achieve weight loss, maintenance, or gain goals effectively.

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Guide

7 MIN READ

How to Calculate Macros for Bulking: A Complete Guide

Calculate the right protein, carbs, and fat split for a lean bulk. Learn why a 200-300 calorie surplus is optimal, how much protein you actually need, and how to avoid excess fat gain.

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Guide

8 MIN READ

How to Calculate Your TDEE for Any Fitness Goal

Calculate your TDEE using 4 research-backed formulas. Learn which formula is most accurate for your body, why most people overestimate activity level, and how to use TDEE for fat loss or muscle gain.

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Guide

8 MIN READ

Intermittent Fasting for Beginners: How to Start

A practical beginner's guide to IF. Which protocol to start with, how to handle hunger, what the research actually shows, and who should avoid fasting entirely.

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