One Rep Max Estimate Calculator
Calculate one rep max estimate quickly with clear inputs, an instant result, and a practical formula.
One Rep Max Estimate measurements
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Result
How to calculate one rep max estimate
This calculator estimates a one-rep max (1RM) — the maximum weight liftable for a single repetition — from a submaximal weight and rep count, using the Epley formula.
How the calculation works
Estimated 1RM = Weight lifted × (1 + Reps completed ÷ 30).
Example
135 lbs lifted for 8 reps: 135×(1+8÷30) = 135×1.267 ≈ 171 lbs.
Frequently asked questions
How is Estimated one-rep max (Epley formula) calculated?
Estimated one-rep max (Epley formula) = [Weight lifted] × (1 + [Reps completed] ÷ 30).
Is the One Rep Max Estimate Calculator free to use?
Yes — every calculator on Simple Calculator Tools is free, runs in your browser, and does not require an account.
One Rep Max Estimate Calculator
Estimated 1RM = Weight lifted × (1 + Reps completed ÷ 30).
Let's understand your one rep max estimate result.
Calculate a result above and this guide will help you interpret it using this calculator's own formula and explanation.
Pro Tips for One Rep Max Estimate
- This estimate is most accurate for rep ranges under about 10 — accuracy declines for higher-rep sets, since the relationship between reps and strength becomes less linear.
- This is one of several 1RM estimation formulas (others include Brzycki and Lombardi) — they typically produce similar but not identical estimates.
Common One Rep Max Estimate Mistakes to Avoid
- Using this formula for very high rep counts (15+), where the estimate becomes considerably less reliable than for lower, more strength-focused rep ranges.
When to Use This Calculator
This calculator estimates a one-rep max (1RM) — the maximum weight liftable for a single repetition — from a submaximal weight and rep count, using the Epley formula.