Hypertrophy Rep Range: How Many Reps Per Set to Grow

The hypertrophy rep range is 6 to 30 reps per set, taken close to failure. Across that whole range, muscle growth comes out about the same. The practical sweet spot is 6 to 12, because it's heavy enough to progress cleanly and light enough to recover from. Go heavier, 1 to 5 reps, when strength is the goal.

What the research says about the hypertrophy rep range

Three papers settle most of this.

Schoenfeld, Grgic, Ogborn and Krieger (2017) pooled 21 studies comparing low-load training (60% of 1RM or less, so roughly 15 reps and up) against high-load training (above 60%, so roughly 12 reps or fewer), with every set taken to failure. Hypertrophy was similar between the two. Strength was a different story: 1RM gains were clearly greater with the heavy loads. So heavy is better for strength, and either works for size.

Lasevicius and colleagues (2018) tested the bottom of the range. Thirty men trained one arm and one leg at 20% of 1RM and the other side at 40%, 60% or 80%, volume matched, for 12 weeks. Quad growth was 8.9% at 20% of 1RM against 20.5%, 20.4% and 19.5% for the other three. Elbow flexors went 11.4% against about 25% for the rest. So 40% and up all grew muscle equally, and 20% didn't. A set at 20% of 1RM is 40 or 50 reps of burning, and it turns out most of those reps don't count.

Schoenfeld, Grgic, Van Every and Plotkin (2021) reviewed the whole "repetition continuum" idea, where heavy builds strength, moderate builds size and light builds endurance. Their conclusion was that muscle growth can be had, and in some cases maximised, across a wide spectrum of loads, and the old three-zone chart doesn't survive contact with the data.

That's the case for "6 to 30 reps works". Now the case for not training at 30.

Why 6 to 12 is still the practical sweet spot

If 8 reps and 25 reps grow the same muscle, the question becomes which one costs less. A few things tilt it toward 6 to 12.

Progression is legible. Adding 2.5 kg to a set of 8 is a clear win. Adding 2.5 kg to a set of 25 is inside the noise, and you'll often just lose 3 reps and not know if you improved.

Sets of 20+ are miserable on compounds. A set of 20 squats near failure is a cardio event with a barbell on your back. Your legs aren't the limit, your lungs and your will are. That means the set stops before the quads have been pushed, which is the whole point of the set.

Heavy singles and triples cost joints and time. Five sets of 3 with 4 minutes rest is 20 minutes for 15 reps. Fine for a powerlifter in a strength block. Expensive for someone trying to fit 14 sets of chest into an hour.

Failure gets harder to judge at both ends. At 3 reps you can grind a rep you shouldn't. At 25 reps you quit from discomfort, not from failure. Around 6 to 12, "two reps left" feels like two reps left.

So the recommendation is: most of your sets in 6 to 12, some in 12 to 20 where it suits the exercise, and 3 to 5 reps only where you specifically want strength.

Rep range by exercise type

The pattern: the more stable the exercise and the smaller the muscle, the higher the reps. The heavier and more technical the lift, the lower.

How to combine rep ranges in a week

You don't need to stay in one zone all week. A simple structure that works on an upper/lower split:

• Day 1, heavier upper: Bench 4 x 5-8, row 4 x 6-8, overhead press 3 x 6-8, then arms 3 x 10-12.
• Day 2, heavier lower: Squat 4 x 5-8, Romanian deadlift 3 x 6-8, leg press 3 x 10-12, leg curl 3 x 10-12.
• Day 3, lighter upper: Incline dumbbell press 3 x 8-12, chest-supported row 4 x 10-12, lateral raises 4 x 12-15, cable fly 3 x 15-20.
• Day 4, lighter lower: Deadlift 3 x 4-6, split squats 3 x 8-10, leg extension 3 x 12-15, calves 4 x 12-15.

Each muscle gets one session leaning heavy and one leaning light. You get the progression clarity of 6 to 8 reps and the joint-friendly volume of 12 to 15 reps in the same week. The full program with rest times is in the best 4 day workout split.

Why close to failure matters more than the number

Every study above has a hidden condition: the sets went to failure or very close to it. Take the failure away and the "6 to 30 reps grow the same" finding falls apart, because the light sets stop recruiting the big fast-twitch fibres. That recruitment only happens near the end of a hard set, when the slow fibres have fatigued and the nervous system pulls in everything it has.

A set of 12 with 6 reps left in the tank isn't a hypertrophy set. It's a warm-up. A set of 12 with 1 rep left is.

The practical rule: 0 to 3 reps in reserve on every working set. Isolation work can go to 0 on the last set. Compounds sit at 1 to 3 because a failed rep under a bar has consequences. Training to failure vs close to failure goes through the evidence and how to learn what 2 reps in reserve feels like.

How to progress within a rep range (double progression)

This is the mechanism that turns a rep range into gains.

1. Pick a range, say 8 to 12. Pick a weight where you get 8 reps with 1 or 2 left.
2. Each session, try to add a rep to each set. 8, 8, 8 becomes 9, 9, 8 becomes 10, 10, 9 and so on.
3. When every set hits 12, add weight. 2.5 kg on upper body, 5 kg on lower body, one dumbbell up for isolation.
4. Reps drop back to around 8. Build them up again.

Worked example on incline dumbbell press, 3 sets, 8 to 12 range:

Five weeks, one weight jump, 13 extra reps across the sets before it. Every one of those weeks was progress, and you could see it. The progressive overload guide has the other methods for when reps stall.

Mistakes with rep ranges

1. Treating 8 to 12 as a rule and going nowhere near failure. The range is only a rep range if the last rep is hard. Twelve easy reps with a weight you could do 20 times is not a set.
2. Using the same reps on every exercise. Squats at 15 reps and lateral raises at 5 reps are both wrong for the same reason. Match the range to the exercise.
3. Changing the rep range every week to confuse the muscle. The muscle isn't confused. You are, because you can't compare week 3 to week 2. Keep a range for a block of at least 4 to 6 weeks.
4. Going heavy on isolation work. A 5-rep curl is an elbow injury with a long fuse. Small muscles, higher reps.
5. Counting half reps. If the range is 8 to 12 and reps 10 to 12 were quarter reps, you did 9. Log 9.

How to track this in Ultra+

Rep ranges only work when you can see what you did last time. In Ultra+, every set shows the previous set for that exercise plus your all-time best set, right where you type the numbers. Double progression stops being a memory exercise. You see 30 kg x 11 from last week and the target for today is 12.

The best set is scored with the Epley formula, so a heavy set of 5 and a lighter set of 12 land on the same scale. Doing 32.5 kg for 9 after 30 kg for 12 shows up as a new best, because the estimated 1RM went up even though the reps went down. If you want to check the numbers yourself, the one rep max calculator uses the same formula.

After the session, the summary shows your total volume and the change from the last time you ran that template. Reps went up, volume went up. That's the whole feedback loop.

Start your free trial and your previous set is on the screen from the first workout.