One Rep Max Calculator

Calculate your one-rep max based on weight and repetitions performed

Weight

Repetitions

Exercise

Biological Sex

Experience Level

Formula Preference

Your Estimated One Rep Max

Reliability: High

0 kg

Formula used: Epley Compare all formulas

Formula	Estimated 1RM	Best For
Average	0 kg	Combined estimate

% of 1RM	Weight	Typical Reps	Training Focus

Reps	Weight	% of 1RM

Strength Classification

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For best accuracy, test with weights allowing 3-5 reps. Predictions become less reliable beyond 10 reps.

Based on formulas validated in the Journal of Strength and Conditioning Research

Using Your One Rep Max in Training

The one rep max calculator gives you a foundation for programming without the risk of maximal testing. Here’s how to interpret and apply these numbers to improve your training.

The Math Behind 1RM Formulas

Several equations can predict your one-rep max, each developed and validated through research. Understanding these formulas helps explain why some work better for certain exercises and individuals.

Brzycki Formula

1RM = Weight ÷ (1.0278 – 0.0278 × Reps)

Developed in 1993, this linear formula works well for bench press tests using 7-10 repetitions. Women often find this formula particularly accurate for upper body exercises.

Epley Formula

1RM = Weight × (1 + 0.0333 × Reps)

One of the most widely used formulas, Epley’s equation shows good accuracy for compound movements like squat, bench press, and deadlift, particularly when using 3-8 repetitions.

Lombardi Formula

1RM = Weight × Reps^0.1

This non-linear formula incorporates an exponential term, making it better at predicting 1RM for men performing bench press and squat.

Mayhew Formula

1RM = (100 × Weight) ÷ (52.2 + 41.9 × e^{-0.055 × Reps})

More complex than others, this formula was found to be accurate for women performing arm curls and other isolation movements, as well as for higher rep ranges.

Research consistently shows these formulas become less accurate as repetitions increase beyond 10. For best results, test with weights you can lift for 3-5 reps with proper form.

Strength Standards by Lift

Your 1RM can help you gauge where you stand compared to established strength benchmarks. These standards vary by exercise, gender, and body weight.

Men’s Strength Standards (% of Body Weight)

Exercise	Beginner	Intermediate	Advanced	Elite
Bench Press	0.8×	1.25×	1.5×	1.8×
Squat	1.25×	1.75×	2.0×	2.5×
Deadlift	1.5×	2.0×	2.5×	3.0×
Overhead Press	0.5×	0.85×	1.0×	1.25×

Women’s Strength Standards (% of Body Weight)

Exercise	Beginner	Intermediate	Advanced	Elite
Bench Press	0.5×	0.8×	1.0×	1.25×
Squat	0.8×	1.4×	1.7×	2.0×
Deadlift	1.0×	1.6×	1.9×	2.4×
Overhead Press	0.3×	0.6×	0.75×	0.9×

These standards should be used as general reference points rather than strict goals. Individual factors like arm and leg length, clavicle length, training history, and genetic factors all influence strength potential.

Percentage-Based Training

One of the most practical applications of knowing your 1RM is designing percentage-based training programs. Different intensity ranges produce specific training effects.

Intensity Range	Rep Range	Primary Training Effect	Recovery Time
90-100% 1RM	1-3	Maximum strength, neural efficiency	48-72+ hours
80-89% 1RM	4-6	Strength, some hypertrophy	36-48 hours
70-79% 1RM	6-10	Strength-hypertrophy balance	24-48 hours
60-69% 1RM	10-15	Hypertrophy, endurance	24-36 hours
Below 60% 1RM	15+	Muscular endurance, technique	12-24 hours

Applying Percentages to Programs

Major strength programs use percentage based loading to structure training. Here’s how some popular methods approach it:

5/3/1 Method

Jim Wendler’s approach uses a “training max” set at 90% of true 1RM as the foundation. A typical four-week cycle looks like:

Week 1: 65%/75%/85% of TM for 5 reps each set
Week 2: 70%/80%/90% of TM for 3 reps each set
Week 3: 75%/85%/95% of TM for 5/3/1 reps
Week 4: 40%/50%/60% of TM for 5 reps (deload)

The final set each day is performed for as many reps as possible, allowing for autoregulation based on daily readiness.

Texas Method

This intermediate program uses three key training days per week:

Volume Day: 5×5 at approximately 80-85% of 5RM (~70-75% of 1RM)
Recovery Day: 2×5 at ~60-65% of 1RM
Intensity Day: 1×5 at 5RM (~87% of 1RM)

Progress is measured by increasing the 5RM weight on intensity day, then adjusting volume day weights accordingly.

Special Considerations for Accuracy

Several factors influence how closely predicted 1RMs match your actual strength capacity. Being aware of these variables helps you interpret results more effectively.

Exercise Differences

Deadlifts often test stronger than predicted, while overhead presses sometimes test weaker. This is due to differences in strength curves and technique demands. Multi-joint compound movements generally show different patterns than isolation exercises.

Experience Effects

Novice lifters typically can’t express their full strength in 1RM tests due to neural efficiency factors. If you’re new to lifting, your actual max might be 5-10% lower than predicted. As you gain experience, this gap typically narrows.

Gender Differences

Research shows women can generally perform more repetitions at a given percentage of 1RM than men, especially for upper body exercises. This means prediction formulas may sometimes overestimate 1RM for female lifters by 5-15%.

Rep Range Influence

Predictions based on 1-5 reps show average errors of 5% or less. Tests using 10+ reps can have error ranges of 10-15%. Above 15 reps, predictions become progressively less reliable as muscular endurance becomes the limiting factor.

Testing Protocols for Accuracy

To get the most accurate prediction of your true 1RM, follow these evidence-based testing guidelines:

Perform proper warm-up – Begin with 5-10 minutes of general cardio, followed by dynamic movements specific to your test exercise.
Ramp up progressively – Start with 50% of estimated 1RM for 5-8 reps, then 70% for 3-5 reps, then 80-85% for your test set.
Choose the right rep range – Select a weight that allows you to complete 3-5 reps with good form but challenges you to reach failure or near-failure.
Maintain consistent technique – Form breakdown affects predictions. Maintain the same range of motion and technique throughout all reps.
Rest adequately – Take 3-5 minutes rest before your test set to ensure ATP replenishment and optimal performance.
Record accurately – Note exact weight and complete repetitions (don’t count partial reps).

For most lifters, submaximal testing every 4-12 weeks provides enough data to track progress without excessive fatigue or injury risk.

Practical Applications

Beyond structuring training percentages, your estimated 1RM has several practical applications:

Progress Tracking

Monitor strength gains over time without maximal testing. A 5% increase in your 5RM typically indicates similar improvement in 1RM strength.

Programming Autoregulation

Adjust working weights based on “reps in reserve” or “RPE” (Rate of Perceived Exertion) for more individualized training.

Load Selection

Choose appropriate weights for specific rep targets without guesswork. For example, if aiming for 8 reps, use approximately 75% of estimated 1RM.

Specialization Phases

Identify strength imbalances between lifts and design training blocks to address lagging movements.

Remember that 1RM predictions are tools, not absolute values. Use them to inform training decisions, but adjust based on how your body responds to the prescribed loads.