Free fitness tool
Estimate one-rep max and training percentages from a recent set, then use ZenFit AI to organize strength workouts safely.
Enter the basics that shape this estimate, then use the interactive calculator after the app loads to adjust the numbers.
exercise
weight used
reps completed
training goal
This output is useful for planning, not for diagnosis or guaranteed results.
This output is useful for planning, not for diagnosis or guaranteed results.
This output is useful for planning, not for diagnosis or guaranteed results.
Uses the Epley-style one-rep max estimate. It is most useful for moderate rep ranges and should not encourage unsafe max attempts.
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.
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
Use the quiz to connect this tool's estimate to workouts, meals, progress tracking, and AI coach context around your real week.
Not always. Many lifters can plan effectively from submaximal sets, especially without a spotter or coach.
No. It varies by exercise, rep range, technique, fatigue, and individual strength endurance.
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