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Lean Bulk Calculator

Estimate a lean bulk calorie surplus, protein target, and expected weekly gain range before personalizing your muscle gain plan in ZenFit AI.

Build my lean bulk plan Use the free estimate first

Estimate your targets

Enter the basics that shape this estimate, then use the interactive calculator after the app loads to adjust the numbers.

Input

maintenance calories

Input

body weight

Input

training level

Input

surplus preference

1

surplus calories

This output is useful for planning, not for diagnosis or guaranteed results.

2

lean bulk target

This output is useful for planning, not for diagnosis or guaranteed results.

3

protein range

This output is useful for planning, not for diagnosis or guaranteed results.

Methodology

Uses estimated maintenance calories, a modest surplus range, and protein-per-kilogram planning ranges for general muscle gain support.

The estimate should be compared with real-world outcomes over time. Body weight trends, training performance, hunger, schedule, sleep, injury status, and consistency can all change what works in practice.

Important safety note

This tool is for general fitness education and planning context. It is not medical advice. If you are pregnant, managing a medical condition, recovering from an injury, changing medication, or unsure whether a calorie or training change is appropriate, speak with a qualified clinician.

Next step

Build the plan behind this result

Use the quiz to connect this tool's estimate to workouts, meals, progress tracking, and AI coach context around your real week.

Build my lean bulk plan

Frequently asked questions

How large should a lean bulk surplus be?

A modest surplus is usually easier to manage than a large one because it supports training while limiting unnecessary fat gain.

Can ZenFit AI turn lean bulk targets into meals and workouts?

Yes. Paid ZenFit AI features can connect calorie surplus, macros, meals, workouts, training calendars, and coach context.

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