Free Strength Calculator

1RM Calculator

Q: How accurate is this 1RM estimate?

It is a practical estimate based on your lifted weight and reps. Accuracy is strongest at lower rep ranges and should be validated against training performance over time.

Q: Should I use estimated 1RM or training max?

Use estimated 1RM to gauge current strength and use a training max to plan repeatable percentage-based programming with manageable fatigue.

Estimate your one-rep max, get your training max, and apply practical percentage-based loading for your next training block.

Enter your lift details

Your result

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Your estimated 1RM will appear here after calculation.

Estimated 1RM

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Training max

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Estimate range

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Load %	Target load	Rep guide

Estimated 1RM is not a true tested max.

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Use the estimate well

Estimated 1RM

A practical strength estimate based on the weight and reps you completed.

Training max

A slightly reduced number to keep percentage work more repeatable and sustainable.

Working percentages

Fast loading targets for your next block without manually calculating each set.

Accuracy guide

1–5 reps: strongest range for heavy strength estimation.
6–10 reps: useful for planning, but fatigue can skew the result.
11–12 reps: treat as a broad estimate, not a true max.

How the 1RM estimate works

This calculator estimates your maximum single-rep strength from the load you lifted and the number of reps completed.

The result is best used for programming targets, not as a replacement for a carefully planned max test.

How to apply the result

Use your estimated 1RM to set working percentages, then review bar speed, technique, recovery, and consistency across the block.

If reps were slow, loose, or close to failure, use the training max for safer loading decisions.

1RM FAQ

How accurate is this 1RM estimate?

Most useful between 1 and 10 reps. Above 10 reps, use it as a rough estimate.

Should I use estimated 1RM or training max?

Use estimated 1RM to understand your current strength ceiling. Use training max when planning repeatable percentage work.

Do I need an account?

No. You can calculate for free; only saving requires login.