One Rep Max Calculator

Estimate your 1RM with Epley, Brzycki, and Lombardi formulas, then convert the result into practical training percentages.

Last updated: 2026-03-18

One rep max calculator

Enter your values

Estimate your 1RM from a submax set, compare three common formulas, and turn the result into usable training loads.

Estimated 1RM

Enter a completed set to estimate your one-rep max and common training percentages.

Calculation History(0)

No calculations yet. Complete a calculation to see it here.

Example calculations

Tap an example to prefill the calculator with sample values.

Classic bench set

225 lb for 5 reps

A common barbell benchmark where the formulas stay fairly tight together.

Result: Epley estimate around 262.5 lb with an 80% load near 210 lb

Intermediate squat

140 kg for 3 reps

A lower-rep strength set where estimated maxes are usually more reliable.

Result: Estimated max around 154 kg with 90% work around 138.5 kg

Higher-rep hypertrophy set

135 lb for 12 reps

Shows how the calculator still works at higher reps, but warns that formula spread grows.

Result: A wider formula range and a reminder to treat high-rep estimates cautiously

How the 1RM estimate works

A one-rep max estimate turns a heavy working set into an approximation of your best possible single. That is useful when you want programming guidance without testing a true max, which can be fatiguing or technically messy.

The formulas here are best treated as a range. If the numbers cluster closely, you have a cleaner estimate. If the spread is wider, especially on higher-rep sets, use the output as guidance and then adjust by bar speed and technique quality.

One rep max FAQs

How to interpret the estimate and use the percentages in training.

Which 1RM formula should I trust most?

Epley is the headline estimate here because it is widely used for general gym programming, but no single formula wins for every athlete. That is why the calculator also shows Brzycki and Lombardi for comparison.

Are the estimates less reliable at high reps?

Yes. As reps climb, fatigue, pacing, and exercise selection introduce more noise. Sets in the 2-to-8 rep range usually produce tighter estimates than sets at 12 or more.

How should I use the training percentages?

Treat them as starting loads for programming. If the bar moves much faster or slower than expected, adjust the actual working weight instead of treating the estimate as absolute truth.

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