1RM (one-rep max) is the maximum weight you can lift for a single repetition with proper form, a widely used reference point for programming training intensity as a percentage, and the number most longevity programmes build their loading around, most working sets in a structured strength program are prescribed as a percentage of this number. Despite how central it is to programming, actually testing a true 1RM directly carries more injury risk than the alternative, safely estimating it from a submaximal set.
- The maximum weight liftable for a single rep with proper form, the standard reference point for programming intensity.
- The Epley formula estimates it from a submaximal weight and rep count, no maximal attempt required.
- Strength standards are commonly tiered (Beginner through Elite) by bodyweight ratio, not a single fixed number.
- Heavy sets of five reps or fewer build comparable strength with meaningfully less risk than an actual max attempt.
Why 1RM is the reference point for programming
Structured strength programs typically prescribe working weights as a percentage of a lifter's 1RM, a set of 5 at 80% of your squat 1RM, for example, rather than a flat, one-size-fits-all number, since the same absolute weight represents very different relative effort for different lifters. Knowing your 1RM, even an estimated one, lets a program scale appropriately to your current strength level.
This is also why 1RM shows up so often in strength standard tables, expressing strength relative to bodyweight and age lets you compare meaningfully across people of different sizes, rather than comparing raw weight lifted, which mostly just reflects body size rather than relative strength.
Why re-estimating matters less over time
Strength gains decelerate sharply with training age. A beginner’s estimate goes stale within weeks, while an experienced lifter’s holds for months, which is the practical answer to how often to re-estimate.
How to estimate 1RM without a max attempt
The Epley formula is a widely used method for estimating 1RM from a submaximal set, a weight you can lift for a known number of reps, without needing to actually attempt a true maximal single lift. The formula essentially extrapolates from how many reps you completed at a given weight to project what your one-rep max would likely be, a set of 5 reps at a solid, controlled weight gives a reasonably reliable estimate.
This matters practically because a true 1RM attempt carries meaningfully more injury risk than a submaximal set, fatigue and form breakdown are far more likely at true maximal loads, and the marginal information gained from an actual max attempt, versus a reliable estimate, rarely justifies that added risk for most people training for general strength and longevity rather than competitive powerlifting specifically.
Where a 1RM sits against strength standards
Strength standards express a lift relative to bodyweight, sex and age across five tiers. The strength standards entry carries the tiers and the kilogram figures behind them.
One-rep max estimator
Estimates your 1RM from a submaximal set, and gives the training loads at each rep range beneath that maximum.
The rep-max chart, and the formulas behind it
Estimating a maximum from a submaximal set relies on a reasonably stable relationship between load and achievable repetitions. That relationship is consistent enough to be useful and variable enough that the output should be treated as an estimate.
The standard percentage chart
- 1 rep — 100% of 1RM
- 2 reps — approximately 95%
- 3 reps — approximately 93%
- 5 reps — approximately 87%
- 8 reps — approximately 80%
- 10 reps — approximately 75%
- 12 reps — approximately 70%
- 15 reps — approximately 65%
The two common formulas
Epley: 1RM = weight × (1 + reps ÷ 30). Brzycki: 1RM = weight × 36 ÷ (37 − reps). They agree closely at low repetitions and diverge as the count rises, with Brzycki generally returning the lower figure.
Worked example: 100 kg for 5 repetitions. Epley gives 100 × (1 + 5/30) = 117 kg. Brzycki gives 100 × 36/32 = 113 kg. A 4 kg spread at five reps, widening substantially by ten.
Why individuals deviate from the chart
Muscle fiber composition drives most of the variation. Someone with a higher proportion of slow-twitch fibers will manage more repetitions at a given percentage, so a formula will overestimate their true maximum. The reverse holds for fast-twitch-dominant lifters.
For example, I happen to be very slow twitch fibre dominant. At 71–73kg, my 1RM squat after two decades of training is 160kg. At 95% I should be able to do 2 reps but I’d likely get 3. At 87%, where I’m supposed to get 5 reps, I’d get 8.
I’ve had training partners in the past who were the complete opposite. Struggling to get 5 reps at 87% but easily out-lifting me after just a year of training.
Exercise choice matters too. Leg press and other machine movements typically allow more repetitions at a given percentage than free-weight squats, where stability and fatigue intervene earlier. Applying a bench-press-derived chart to a deadlift will mislead.
Getting a usable estimate
Use a set of three to six repetitions taken close to failure — around RPE 9. Higher-rep sets carry compounding error, and sets stopped well short of failure understate the result badly. Warm up thoroughly, and take the estimate from a single quality set rather than the third set of a fatiguing session.
Why maximal testing is usually avoided
For longevity purposes, an estimate is sufficient to place you on the strength standards and to set training loads. A true one-repetition maximum requires a spotter, produces significant fatigue, and carries injury risk that returns nothing a good estimate doesn’t already provide.
Where 1RM estimation fits in your training
The usual framing treats “testing your max” as a natural milestone, without weighing the injury risk against a submaximal estimate that gets you the same number.
Estimate from a recent, honest working set. Three to five reps at a weight with a rep or two left in reserve is enough. Feed that into one of the formulas above and you have a working 1RM without ever attempting a single.
Re-estimate every few months as you get stronger. A number from six months ago is a record of who you were, not a basis for this week’s loading.
The app estimates your 1RM from your actual logged sets, no maximal testing required.
Sources
Key references for the claims on this page. Where a figure is attributed to a specific study or body, it is named here.
- Epley B. Poundage Chart. Boyd Epley Workout. Lincoln, NE: Body Enterprises, 1985. Origin of the Epley formula, 1RM = weight × (1 + reps ÷ 30).
- Brzycki M. Strength testing: predicting a one-rep max from reps-to-fatigue. Journal of Physical Education, Recreation & Dance, 1993;64(1):88-90. Origin of the Brzycki formula.
- Strength Level community data, capped at the Advanced tier, used for compound lift scoring.
- Latella C, et al. Sports Medicine, 2024. 9,259 competitive powerlifters, up to 17 years of IPF competition data; strength gains decelerate sharply with training age.
Frequently asked
What is the best squat or deadlift 1RM for longevity?
Longevity Coach IQ targets Intermediate or better on all four main lifts, scored relative to your own bodyweight and age rather than as an absolute number. That threshold is where strength stops being a limiting factor for daily function. Pushing toward Advanced or Elite adds diminishing longevity return against rising injury risk.
What is a 1RM?
The maximum weight liftable for a single repetition with proper form, used as a reference point for programming training intensity.
How do you calculate your one rep max?
The usual approach is a submaximal set taken close to failure, put through a formula such as Epley. Accuracy degrades as the rep count climbs, so a set of three to six reps gives a better estimate than a set of fifteen.
Is it safe to test a true one rep max?
It can be done safely with experience, a spotter and a proper warm-up, but the risk-to-benefit ratio is poor if you are training for health rather than competing. The estimate is close enough for programming purposes.
What percentage of 1RM should I lift?
Most productive strength work sits somewhere between 70 and 85 percent for multiple sets, depending on the phase. Very heavy singles are largely a competition skill rather than a requirement for getting stronger.
Why is my estimated 1RM different from my real one?
Rep-max formulas assume an average relationship between endurance and maximal strength, and individuals vary considerably. Someone with high muscular endurance will have their max overestimated, and the reverse is also true.
How often should you retest your max?
Every couple of months is plenty. Strength doesn’t change fast enough to justify weekly testing, and frequent maximal attempts add fatigue that competes with the training actually producing the progress.