Your one rep max: the heaviest weight you can lift once, with proper technique, on a given exercise. It is the reference percentage-based programs are written against (“5 × 5 at 80 %”).

Which formula is more accurate, Epley or Brzycki?

They are almost identical between 2 and 10 reps, and exactly equal at 10. Below 10 reps Epley gives a slightly higher 1RM and Brzycki a more conservative one. Brzycki fits best from 1 to 6 reps and Epley from 6 to 10. Above 12, neither is reliable.

How many reps should I use to estimate it?

A set of 3 to 6 reps taken to failure, or one rep short of it. The more reps, the more the set measures your endurance rather than your strength, and the more the formula misses. That is why the app does not estimate a 1RM from sets above 12.

Do I need to test my real 1RM?

For training, hardly ever. A real max is fatiguing, riskier technically and only valid for that day. A hard low-rep set estimates your 1RM with a small error, and you can take it from any normal session.

What is my 1RM useful for?

To pick weights in percentage-based programs and, above all, to compare sessions with different rep ranges: 175 lb × 8 and 195 lb × 4 cannot be compared at a glance, but their estimated 1RMs can. Tracked week by week, it is the best sign of whether you are getting stronger.

Does the app calculate my 1RM?

Yes. Every set you log gets its estimated 1RM with the Epley formula, and each exercise’s progress chart shows how it moves, next to your heaviest weight and your volume.

Calculator

1RM calculator (one rep max)

Your one rep max without having to test it: enter the weight and reps of a hard set and get your estimated 1RM, with the weights for every percentage.

Your set

Unit

Weight lifted

Reps

1 to 12. Best from a set of 3 to 6 taken to failure, or one rep short of it.

Calculated in your browser: nothing is sent or stored.

Your estimated 1RM262.5lb

Epley: 262.5 lb; The one the app uses.
Brzycki: 253.1 lb; Sharper for sets of 1 to 6.

The app already works out the estimated 1RM of every exercise from the sets you log, and shows you how it climbs week after week.

Your 1RM, worked out every session

Log your sets in the app and see the estimated 1RM of every exercise, no maths needed.

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Percentage chart

% of 1RM	Weight	Approx. reps	Use
100 %	262.5 lb	1	Max strength
95 %	249.4 lb	2	Max strength
90 %	236.3 lb	3	Max strength
85 %	223.1 lb	5	Strength
80 %	210 lb	8	Strength
75 %	196.9 lb	10	Hypertrophy
70 %	183.8 lb	13	Hypertrophy
65 %	170.6 lb	16	Hypertrophy
60 %	157.5 lb	20	Hypertrophy
55 %	144.4 lb	25	Technique and warm-up
50 %	131.3 lb	30	Technique and warm-up

Weight for each rep max

What you should be able to lift all-out for each number of reps, with both formulas.

Reps	Epley	Brzycki
1	262.5 lb	253.1 lb
2	246.1 lb	246.1 lb
3	238.6 lb	239.1 lb
4	231.6 lb	232 lb
5	225 lb	225 lb
6	218.8 lb	218 lb
7	212.8 lb	210.9 lb
8	207.2 lb	203.9 lb
9	201.9 lb	196.9 lb
10	196.9 lb	189.8 lb
11	192.1 lb	182.8 lb
12	187.5 lb	175.8 lb

It is an estimate: two people with the same 1RM do not get the same reps at 80 %. Use it to pick weights and follow the trend, not as a record.

How it works

1
Epley
1RM = weight × (1 + reps ÷ 30). The formula the app uses for every exercise’s estimated 1RM, and the best fit from 6 to 10 reps. 225 lb × 5 is 262.5 lb.
2
Brzycki
1RM = weight × 36 ÷ (37 − reps). More conservative and sharper for short sets, 1 to 6 reps. Both give exactly the same result at 10 reps; below that, Epley reads a little higher.
3
From 1RM to working weights
Each percentage with the reps you get from solving Epley backwards: about 8 at 80 %, about 10 at 75 %. A starting point: what decides is how many reps you leave in the tank that day.

Using your 1RM to make progress

Which signal to trust, how often to check it and how to program once you no longer add weight every week.

Measuring progress: what to log and how to read it

Estimated 1RM, effective volume, RIR and body measurements. Which signal is reliable, how often to look at it, and when to act.

Keep reading

Stop guessing at your progress: measure it

Data, RIR, e1RM and volume control

Keep reading

Frequently asked questions

What is a 1RM?: Your one rep max: the heaviest weight you can lift once, with proper technique, on a given exercise. It is the reference percentage-based programs are written against (“5 × 5 at 80 %”).
Which formula is more accurate, Epley or Brzycki?: They are almost identical between 2 and 10 reps, and exactly equal at 10. Below 10 reps Epley gives a slightly higher 1RM and Brzycki a more conservative one. Brzycki fits best from 1 to 6 reps and Epley from 6 to 10. Above 12, neither is reliable.
How many reps should I use to estimate it?: A set of 3 to 6 reps taken to failure, or one rep short of it. The more reps, the more the set measures your endurance rather than your strength, and the more the formula misses. That is why the app does not estimate a 1RM from sets above 12.
Do I need to test my real 1RM?: For training, hardly ever. A real max is fatiguing, riskier technically and only valid for that day. A hard low-rep set estimates your 1RM with a small error, and you can take it from any normal session.
What is my 1RM useful for?: To pick weights in percentage-based programs and, above all, to compare sessions with different rep ranges: 175 lb × 8 and 195 lb × 4 cannot be compared at a glance, but their estimated 1RMs can. Tracked week by week, it is the best sign of whether you are getting stronger.
Does the app calculate my 1RM?: Yes. Every set you log gets its estimated 1RM with the Epley formula, and each exercise’s progress chart shows how it moves, next to your heaviest weight and your volume.

Your strength, exercise by exercise

My PR works out the estimated 1RM of every exercise from the sets you log and draws the curve: you will know if you are progressing without a single max test.

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