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

Use a recent clean working set that finished close to your technical limit, without form breaking down. Do not use a warm-up set.

Your result

Calculated just now

Your estimated 1RM will appear here after calculation.

Estimated 1RM

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Programming max (90%)

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Estimate range

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% of estimated 1RM	Target load	Typical working reps

Use the estimate to guide training, not as a weight to attempt today.

Strength stopped moving? Diagnose the plateau

Use the estimate well

Estimated 1RM

A practical strength estimate from a clean working set completed close to your technical limit.

Training max

A 90% programming baseline that keeps percentage work more repeatable and leaves room for daily readiness.

Working percentages

Starting loads for your next block. Technique, bar speed, and clean reps still decide whether the load is right that day.

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 technique changed or the final reps slowed sharply, base the next block on the programming max and adjust from clean performance.

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.