How do I calculate my one rep max?

Enter the weight you lifted and the number of reps you completed in the calculator above. It estimates your one rep max (1RM) using seven proven formulas including Epley, Brzycki, and Wathan. For the most accurate result, use a weight you can lift for 3-8 reps with good form.

What is the Epley formula for 1RM?

The Epley formula is: 1RM = Weight x (1 + Reps / 30). For example, if you bench press 185 lbs for 5 reps, your estimated 1RM is 185 x (1 + 5/30) = 215.8 lbs. It is the most widely used 1RM formula and works well for 1-10 reps.

How accurate are one rep max calculators?

One rep max calculators are most accurate when using a weight you can lift for 3-8 reps close to failure. Accuracy decreases significantly above 10 reps. Results are estimates -- your actual 1RM may vary based on technique, fatigue, and training experience. This calculator averages seven formulas to improve reliability.

One Rep Max Calculator - Estimate Your 1RM & Strength Level

Estimated One Rep Max

Average across 7 formulas

Formula Breakdown

Your Strength Level

Training Percentages

Use these percentages to program your training based on your estimated 1RM.

% of 1RM	Weight	Reps	Training Goal

Suggested Warmup Sets

Warmup ramp to your estimated 1RM. Adjust based on how you feel.

Set	Weight	Reps	Purpose

How to Calculate Your One Rep Max

Your one rep max (1RM) is the maximum weight you can lift for a single repetition of a given exercise. Knowing your 1RM is essential for programming effective training -- most strength and hypertrophy programs prescribe weights as a percentage of your 1RM.

Rather than attempting a true 1RM (which carries injury risk), you can estimate it from a submaximal set. Simply enter the weight you lifted and the number of reps you completed, and this calculator will estimate your 1RM using seven well-established formulas.

The Formulas

This calculator uses seven peer-reviewed formulas to estimate your 1RM:

Epley (1985) -- The most widely used formula. Works well for 1-10 reps.
Brzycki (1993) -- Very accurate for low rep ranges (1-7 reps). Popular in academic research.
Wathan (1994) -- Exponential model often considered the most accurate overall.
Lander (1985) -- Good accuracy across moderate rep ranges.
Lombardi (1989) -- Power-based formula. Tends toward conservative estimates.
Mayhew et al. (1992) -- Exponential model that handles higher rep ranges (8-15) well.
O'Conner et al. (1989) -- Simple linear model. Conservative but reliable.

We display the average across all seven formulas as your primary estimate. For the most accurate result, use a weight you can lift for 3-8 reps. Accuracy decreases above 10 reps.

Strength Standards

Enter your bodyweight and sex to see how your estimated 1RM compares to population-level strength standards. These standards are based on publicly available data from competitive powerlifting and gym populations, categorized into five levels:

Beginner -- Less than 6 months of training. Stronger than roughly 5% of lifters.
Novice -- 6-12 months of consistent training. Stronger than roughly 20% of lifters.
Intermediate -- 1-3 years of dedicated training. Stronger than roughly 50% of lifters.
Advanced -- 3-5+ years of serious training. Competitive at a local level.
Elite -- 5+ years of dedicated training. Competitive at regional or national level.

Tips for Accurate Results

Use a weight you can lift with good form for 3-8 reps.
Take the set close to failure (1-2 reps in reserve) for the best accuracy.
Accuracy decreases significantly above 10 reps.
Results are estimates -- your actual 1RM may vary based on technique, fatigue, and other factors.
Never attempt a true 1RM without a spotter and proper warmup.

Calculate Your 1RM