How to Calculate Your One Rep Max, Explained by a Strength and Conditioning Coach

Finding out the maximum amount of weight you can push, squat or deadlift – your one rep max (1RM) – has a use far beyond simple bragging rights.

'If you're trying to add strength and muscle for aesthetics or sport, then knowing your 1RM is indispensable,' says Dr Nicholas Gill, who has been the strength and conditioning coach for the New Zealand rugby team for the last 16 years. 'By training at a specific percentage of your 1 rep max you can put a calculated amount of stress on a muscle over a certain period of time. Such specificity will create the fastest rate of muscle growth.'

Ready to fast track your gains? Use our formula to calculate your one rep max, and then cross-reference your magic number with our percentage goals to ensure you're working your muscles in the most effective way possible.

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How to Calculate Your 1 Rep Max

Calculate your 1 rep max using this 1 rep max calculator, created by the University of New Mexico.

For your upper body, find the heaviest weight you can bench, deadlift or squat 4-to-6 times and plug it into this equation: (4-to-6RM x 1.1307) + 0.6998.

So, if you can do 5 reps of 60kg, then according to the formula – (60 x 1.1307) + 0.6998 – your 1RM will be 68.5kg. For lower body use this formula: (4-to-6RM x 1.09703) + 14.2546.

Simple, huh? And now you have calculated your 1 rep max, you can choose the right volume and intensity of training to suit your goals. But if you need some help with that, keep reading.

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How Much Weight You Should Be Lifting?

Knowing how to calculate your 1 rep max is one thing, but knowing how to use that information is where the real power lies. Below, Gill explains how by lifting different percentages of your calculated 1 rep max, you can hit your training goals, whether you're looking to become bigger, stronger or more explosive.

50% of Your 1RM

Best for: Explosive power

'If you want to improve the pace and speed of your muscles on the sports field, this is the weight for you,' says Gill. 'It's especially good for those who need to move very quickly, such as boxers.'

Use It: The perfect combination for every sportsman is to do 3-to-6 sets of 3-to-4 reps of explosive fast reps. Use a weight that is 50% of your 1RM. This will teach your muscles to be strong, powerful and fast without becoming too big, bulky and slow – the hallmarks of a finely tuned sportsman.

70% of Your 1RM

Best for: Endurance

'This is good for sportsmen who cover long distances as it trains your muscles to keep moving while shifting moderate loads,' says Gill.

Use It: If you're an endurance athlete or just want to get leaner then use weights in no-rest circuits consisting of 4-to-10 exercises. Do 12-to-20 reps. This burns calories and hikes up your metabolism for up to 12 hours after exercise.

80% of Your 1RM

Best for: Muscle

'A tough weight but one that lets you do a fair number of reps,' Gill explains. 'So you will stress your muscle fibres enough to force them to thicken and get bigger."

Use It: This is standard weight-lifting practice, so stick with sets of 7-to-12 reps so you can exert enough stress on your muscles to force them to grow larger. The key here is short rest periods of 30-to-60 secs to fully tax the muscle.

90% of Your 1RM

Best for: Power

'If you want to create maximal force quickly then you need to move heavy loads with speed,' says Gill. 'Performance athletes use this kind of training.'

Use It: During each repetition accelerate the bar as fast as possible while staying in control with good form. Only do 3-to-4 reps then take a 2-to-3 minute rest to recover between the 3-to-4 sets.

95% of Your 1RM

Best for: Strength

'The upper tier of strength development, this weight will help push you past your old limits in the shortest possible time,' Gill says.

Use It: Always use a spotter and do just 1-to-3 reps per set to avoid injury. Only train with a weight this heavy for 6-to-12 weeks at a time, otherwise your nervous system will start to fatigue, which can lead to illness and require some time out.

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How Can You Improve Your One-rep Max?

After you've calculated your 1 rep max, the basis of improving it will involve strength training using progressive overload consistently. Progressive overload means to increase the volume of your work over time. This could include increasing reps, sets, weight, range of movement or decreasing rest time when your workouts begin to feel a little easier, in order to keep them challenging and ensure your muscles continue to adapt and get stronger.

In a study published by PeerJ, when the calculated 1 rep max of 41 participants was assessed after an 8-week training period , increasing both reps and load led to increased strength.

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What’s a 'Good' One Rep Max for the Squat, Bench, and Deadlift?

We hate to sound like a broken record, but the answer to this question will be individual to you and your body. Just like all of our physical efforts, they can be greatly affected by our genetics, muscle size, neural drive, tendons and leverages (length of limbs). We know that we can adjust our training to maximise our potential despite these variables, but they will certainly play a part. However, if you'd like to know some good ball park goals to aim for in your quest for a weight area boast-worthy one rep max, keep listening.

If you need to some figures to work towards, Trainer and powerlifter Jeff Nippard recommends the following 1-rep max goals for men: