How does the O'Conner formula compare to Epley?

O'Conner (weight × 1.025×reps) gives slightly lower estimates than Epley at moderate reps, making it more conservative. It is useful for beginners who prefer not to overestimate their maximum.

What rep range is best for O'Conner?

O'Conner is most accurate for 1–10 reps. For 15+ reps, the linear approximation underestimates actual 1RM versus more sophisticated formulas.

1RM Calculator — O’Conner Formula

Estimate one-rep max using the O'Conner formula: weight × (1 + 0.025 × reps). Simple, linear approximation suitable for beginner to intermediate lifters.

1RM O'Conner

Estimate one-rep max using the O'Conner formula: weight × (1 + 0.025 × reps). Simple, linear approximation suitable for beginner to intermediate lifters.

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Enter values above and press Calculate to see the result.

How It Works

Estimate one-rep max using the O'Conner formula: weight × (1 + 0.025 × reps). Simple, linear approximation suitable for beginner to intermediate lifters

Each component has a specific meaning:

O'Conner formula: weight × (1 + 0 — The o'conner formula: weight × (1 + 0 recorded for the scenario being assessed.

Note: Interpret the 1rm o'conner result against the thresholds and context described above.

How to Use

Enter the O'Conner formula: weight × (1 + 0 for the scenario you are assessing. Estimate one-rep max using the O'Conner formula: weight × (1 + 0.025 × reps). Simple, linear approximation suitable for beginner to intermediate lifters. Use the 1rm o'conner result to inform your calculation.