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Use this One Rep Max (1RM) Calculator to estimate the maximum weight you can lift for a single repetition based on the number of repetitions you can perform with a certain weight. For the most accurate estimate, please use a weight that you can lift between 1 and 10 times. Refer to the "Estimation methods" section for more detail on the formulas used and how this calculator works.
Last updated: February 2, 2026
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For the most accurate estimate, use a weight you can lift between 1 and 10 times.
Your One Rep Max (1RM)
116.67 kg
Using Epley formula
| % of 1RM | Weight | Training Goal |
|---|---|---|
| 50% | 58.33 kg | Explosive Power |
| 60% | 70.00 kg | Explosive Power |
| 70% | 81.67 kg | Muscle Endurance |
| 80% | 93.33 kg | Muscle Growth |
| 85% | 99.17 kg | Muscle Growth |
| 90% | 105.00 kg | Strength & Power |
| 95% | 110.83 kg | Strength & Power |
| 100% | 116.67 kg | Strength & Power |
Note: These are estimates. For the most accurate 1RM, use a weight you can lift for fewer reps (1-5). Always use proper form and consider using a spotter when training near your maximum.
A "one rep max" (one-repetition maximum) is the maximum weight a person can lift for one complete repetition of a specific exercise while maintaining proper form. It is a measure that is commonly used in weightlifting competitions since it represents the peak force that a person's muscles can generate in an all-out effort.
A person's one rep max typically differs based on the exercise, whether it be a bench press, squat, deadlift, overhead press, or whatever other exercise is being performed. Thus, it is important to measure a one rep max for a given exercise rather than applying a one rep max in one exercise to other exercises.
Knowing your one rep max (1RM) is valuable because it provides a quantitative measure (or estimate) of your maximal strength for a given exercise, which enables you to design a workout program and train accordingly based on your goals.
For example, you can use your 1RM to manage your targeted training intensity. This enables you to design a workout program that is challenging enough to promote strength gain while also ensuring proper technique and safety.
Since it provides a quantitative measure, knowing your 1RM also allows you to track your strength progress over time and set goals for improvement. Without a quantitative measure, it can be difficult to motivate ourselves to train. Seeing improvement in your 1RM can help motivate you to train, or if you don't see improvement, you can use your 1RM to adjust your workout program to help you achieve your desired strength gains.
The two primary methods for measuring one rep max are direct measurement by performing a strength test for a given exercise and using estimation methods. There are advantages and disadvantages to using either method, as described below.
Directly measuring one rep max involves progressively increasing the weight as you perform a specific exercise. As you increase the weight, taking breaks between each trial, the number of repetitions of the exercise you can perform should continue to decrease until your muscles reach failure and you can only perform one repetition of the exercise with proper form.
This method of measuring one rep max can be dangerous, and it is important to only attempt using direct measurement for exercises you are experienced in performing, ideally with the help of a spotter. The steps for directly measuring your one rep max are generally as follows:
There are various formulas used to estimate one rep max. This calculator provides calculations for the Epley, Brzycki, and Lombardi formulas:
1RM = Weight × (1 + Reps/30)1RM = Weight × (36 / (37 - Reps))1RM = Weight × (Reps^0.10)The formulas are relatively straightforward; to use them, just plug the amount of weight lifted and the number of repetitions at that weight for a given exercise. The two most popular formulas are the Epley and Brzycki formulas. These formulas return similar results and are generally within 10% or so of a person's actual one rep max, though in some cases it can vary to a larger degree. For the most accurate estimate, use a weight you can lift for fewer reps (1-5 repetitions).
Once you have measured your one rep max, you can use it to help manage your targeted training intensity based on your strength goals. In general, lifting at a certain percentage of your one rep max promotes different things. Below is a general guideline for targeting strength, endurance, and muscle growth:
Lifting a lower number of reps at a lighter weight can help with promoting explosive power. Since it is a lighter weight and lower number of reps, try to keep the breaks between your sets shorter.
Lifting at around 70% of your 1RM for more repetitions helps promote muscle endurance.
Lifting in this range can help with muscle growth.
Lifting in this range promotes a combination of muscle growth, power, and overall strength. Since you are training within or at the upper range of your one rep max, use a spotter whenever possible to decrease risk of injury.
Building strength requires consistency. It is much more difficult to build strength than it is to maintain it.
It is definitely possible to overtrain. Muscles need time to recover and grow, and pushing them to their limits constantly can negatively impact your strength goals, especially in the case of injury. If your muscles are too fatigued, you will not be able to train them as effectively, and are more likely to injure yourself.
In the beginning, just repeatedly performing the exercise you want to improve will likely result in strength gains. However, eventually it will likely lead to a plateau. This is in part because muscles adapt, and at some point will need to be trained differently in order for you to observe further strength gains.
Result: One Rep Max = 116.7 kg
This means you can estimate lifting 116.7 kg for one repetition based on being able to lift 100 kg for 5 repetitions using the Epley formula.
Disclaimer: Always consult with a qualified fitness professional or healthcare provider before engaging in maximal strength testing or starting a new exercise program. Safety should be the top priority when assessing and training for maximal strength.
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