Estimate your one-repetition maximum from the weight lifted and repetitions completed, then view percentage-based training loads for strength, hypertrophy, technique, and safer workout-planning decisions.
Estimated 1RM (Epley) = Weight × (1 + Repetitions ÷ 30)The result is based on the entered workload, time, distance, repetitions, body weight or heart-rate assumptions. Device accuracy, terrain, temperature, technique, fitness level and recovery can cause real performance to differ.
A One Rep Max Calculator estimates the maximum weight you can lift for one complete repetition of an exercise. Enter the weight lifted and the number of repetitions completed to estimate your one-repetition maximum, commonly written as 1RM. The result can help you select training weights, compare strength progress, and plan percentage-based workouts.
To estimate your one rep max, use the weight from a challenging set and the number of repetitions completed with proper form. For better accuracy, choose a set of approximately 2–10 repetitions performed close to muscular failure.
If you completed exactly one repetition, the weight lifted is your actual 1RM for that exercise. Estimates become less reliable when calculated from high-repetition sets.
A commonly used calculation is the Epley formula:
Estimated 1RM = Weight × (1 + Repetitions ÷ 30)
The Brzycki formula is another widely used option:
Estimated 1RM = Weight × 36 ÷ (37 − Repetitions)
Both formulas provide estimates rather than guaranteed maximums. Results may differ because each formula models the relationship between repetitions and maximum strength differently.
Suppose you bench press 185 pounds for 5 repetitions. Using the Epley formula:
Starting weight: 185 lb
Repetitions: 5
Calculation: 185 × (1 + 5 ÷ 30) = 215.83
Estimated one rep max: approximately 216 lb
If practical loading requires standard weight plates, you might round the result to 215 pounds.
The following table shows common training percentages for an estimated 1RM of 200 pounds. Actual programming should also account for exercise type, experience, fatigue, and training goals.
| Percentage of 1RM | Training Weight | Common Use |
|---|---|---|
| 100% | 200 lb | Maximum single |
| 95% | 190 lb | Heavy singles |
| 90% | 180 lb | Strength training |
| 85% | 170 lb | Heavy strength sets |
| 80% | 160 lb | Strength and muscle development |
| 75% | 150 lb | Moderate repetition work |
| 70% | 140 lb | Hypertrophy and technique |
| 65% | 130 lb | Volume training |
| 60% | 120 lb | Speed or technique work |
| 55% | 110 lb | Light training |
| 50% | 100 lb | Warm-up or technique practice |
| 45% | 90 lb | Light warm-up |
| 40% | 80 lb | Movement preparation |
| 35% | 70 lb | Easy warm-up |
| 30% | 60 lb | Very light practice |
These percentages are general guidelines. The number of achievable repetitions at a given percentage varies between individuals and exercises.
One rep max, abbreviated as 1RM, is the greatest weight a person can lift once through the required range of motion with acceptable technique. It is exercise-specific, meaning a bench press 1RM cannot be used as the 1RM for a squat, deadlift, or another movement.
An actual 1RM is measured by performing a maximum single repetition. An estimated 1RM is calculated from a lighter multi-repetition set. Estimation avoids the need for frequent maximal attempts, but the result can be affected by repetition count, technique, fatigue, exercise selection, and individual muscular endurance.
For a more dependable estimate, use a recent set of 10 repetitions or fewer. Record only repetitions completed through a consistent range of motion without assistance.
One rep max is the maximum weight you can lift for one complete repetition of a specific exercise while maintaining acceptable form.
Using the Epley formula, multiply the lifted weight by one plus the repetition count divided by 30: 1RM = Weight × (1 + Repetitions ÷ 30).
It provides an estimate. Accuracy is generally better with lower-repetition sets performed close to failure and may decrease when using sets above approximately 10 repetitions.
You may use either pounds or kilograms. The estimated 1RM remains in the same unit as the entered weight. Do not mix units within the calculation.
Formulas such as Epley and Brzycki use different mathematical models. Small differences are expected, particularly when more repetitions are entered.
Round the result to a weight you can safely load with the available plates. For example, an estimate of 216 pounds may be rounded to 215 pounds.
Calculate using a recent, representative effort rather than a personal best from a different condition. Recalculate when distance, duration, load or body weight changes materially.
Use a recent, challenging set completed with consistent technique and a full range of motion. Sets containing approximately 2–10 repetitions generally produce more useful estimates than high-repetition sets. The final repetition should be difficult, but repetitions completed with assistance or significantly altered form should not be counted.
After estimating your one rep max, multiply it by the desired training percentage:
Training Weight = Estimated 1RM × Training Percentage
For example, if your estimated 1RM is 250 pounds and your program requires 80% of 1RM:
250 × 0.80 = 200 pounds
Your planned training weight would be 200 pounds. Round calculated loads to a weight that can be safely created using the available plates.
| 1RM Range | General Training Focus | Typical Use |
|---|---|---|
| 90%–100% | Maximum strength | Heavy singles and low-repetition work |
| 80%–89% | Strength | Heavy working sets |
| 65%–79% | Strength and hypertrophy | Moderate-load volume training |
| 50%–64% | Technique and speed | Light practice, warm-ups, or explosive work |
| Below 50% | Movement preparation | Easy warm-ups and technique rehearsal |
These ranges are general guidelines, not fixed prescriptions. Appropriate loads depend on training experience, exercise selection, repetition target, recovery, and program design.
A one rep max is not a permanent number. Performance can vary between sessions because of sleep, nutrition, stress, warm-up quality, fatigue, equipment, exercise technique, and rest between sets. Small changes do not necessarily indicate a meaningful gain or loss in strength.
For consistent comparisons, test the same exercise variation under similar conditions. For example, compare a paused bench press only with previous paused bench press results rather than with touch-and-go repetitions.
Calculate a separate 1RM for every exercise. A squat estimate applies only to the squat variation performed, while a bench press estimate applies only to that bench press variation. Machines, free weights, grip widths, bar positions, ranges of motion, and equipment setups can produce different results.
The calculator can estimate a one rep max using either pounds or kilograms. The output remains in the same unit as the entered weight.
1 kilogram = approximately 2.20462 pounds
1 pound = approximately 0.453592 kilograms
Converting units does not change relative strength; it only changes how the weight is expressed. Round the converted result according to the plates available in your gym.
An estimated 1RM allows you to plan training without regularly performing maximum attempts. If you test an actual maximum, use an appropriate warm-up, secure equipment, proper technique, safety arms or spotters when applicable, and enough recovery between attempts.
Stop if you experience sharp pain, dizziness, unusual shortness of breath, or a loss of safe technique. People who are new to resistance training, returning after an injury, or managing a medical condition should seek appropriate professional guidance before attempting maximal lifts.