One Rep Max Calculator | Estimate 1RM From Weight & Reps

Q: How is estimated 1RM calculated on this page?

The dark Estimated 1RM readout is the rounded average of the Brzycki and Epley formulas from your weight and rep count. Brzycki uses 1RM=w/(1.0278−0.0278r)1RM = w / (1.0278 - 0.0278r)1RM=w/(1.0278−0.0278r); Epley uses 1RM=w(1+r/30)1RM = w(1 + r/30)1RM=w(1+r/30). Exercise choice labels your saved snapshot only; it does not change the math.

Q: Which rep counts work best?

Formulas on this page clamp reps to 1–10 for the calculation. The field accepts up to 20, but if you enter more than 10 you will see an amber warning and the math runs as if you entered 10. For programming estimates, a hard set of about 3–8 reps with good form is the usual sweet spot.

Q: What does the % of 1RM table show?

The % of 1RM table lists training weights from 95% down to 50% of your estimated max in the units you selected (kg or lb). Use it to pick working weights for percentage-based programs, for example 85% for heavy triples.

Q: What is the Rep-max table?

The Rep-max (inverse Brzycki) table predicts the weight you could move for rep counts 2 through 12 if your estimated 1RM were exact. It applies the Brzycki relationship in reverse from the averaged 1RM, not a separate test.

Q: When does the Wilks score appear?

Wilks shows when you enter a positive bodyweight and sex under the optional Wilks block. It uses the classic coefficient with your estimated 1RM in kg internally. Bodyweight does not change the 1RM estimate or the load tables.

Q: What does Save snapshot do?

Save snapshot stores one result in your browser: exercise label, estimated 1RM (kg internally), and today's date. It appears below the button until you click Clear. Nothing is sent to a server.

Training weights as percent of estimated one-rep max
%	kg
95%	109
90%	103
85%	97
80%	92
75%	86
70%	80
65%	74
60%	69
55%	63
50%	57

Estimated weight for each rep count from inverse Brzycki
Reps	kg
2	111
3	108
4	105
5	102
6	99
7	95
8	92
9	89
10	86
11	83
12	80

Reading your estimated 1RM and load tables

After you enter a submax set, the Results column shows your averaged 1RM, optional Wilks score, and two weight tables you can use for your next session.

Example: 100 kg × 5 reps, bench (defaults)

With kg selected, Bench press, 100 kg lifted, and 5 reps, Brzycki gives about 112.5 kg, Epley about 116.7 kg, and the headline Estimated 1RM rounds their average to 115 kg. At 85% the % of 1RM table shows about 97 kg for working sets.

% of 1RM and Rep-max tables

The % of 1RM table steps from 95% to 50% in five-point jumps. The Rep-max table lists predicted weights for 2–12 reps from inverse Brzycki. Both tables follow the unit toggle (kg or lb) and update when you change weight or reps.

Save snapshot and safety note

Use Save snapshot to keep one local record of this estimate (exercise name, 1RM, date). The amber banner at the top reminds you to use a submax set rather than a true max attempt unless you are experienced. This tool supports programming; it is not medical or coaching advice.

One Rep Max Calculator: estimate 1RM from weight and reps

After you enter a submax set, read the averaged 1RM in Results, pick working weights from the percentage table, and check rep-max rows or Wilks when you need them.

What this one rep max calculator returns

This one rep max calculator estimates the heaviest single rep you could likely perform today from a safer submaximal set you already completed. It averages the Brzycki and Epley predictions, then builds training weights as percentages of that estimate and rep-max rows for 2–12 reps. It does not replace coached technique checks, medical clearance, or a true competition max attempt.

Inputs:

Weight lifted, rep count (formulas use 1–10), unit toggle, optional exercise label, optional bodyweight and sex for Wilks.
Outputs:

Estimated 1RM, % of 1RM table (95–50%), Rep-max table (2–12 reps), optional Wilks, optional local save.
Limits:

Reps above 10 trigger a warning and clamp to 10 in the math. 1RM is lift-specific; run each exercise separately. Wilks uses the classic formula, not current IPF GL points.

How the math works

Brzycki predicts one-rep max from the weight you lifted and the reps you completed. In plain form, Brzycki divides your weight by a rep factor: 1RM = w ÷ (1.0278 − 0.0278 × r).

Epley uses a straight multiplier instead: 1RM = w × (1 + r ÷ 30).

This page shows the arithmetic mean of those two estimates, rounded in the units you picked. The percentage table multiplies that average; the rep-max table applies the Brzycki denominator in reverse. With the default inputs (100 kg for 5 reps), the headline estimate is about 115 kg.

Controls on this page

Lift inputs are on the left; Results and tables are on the right.

Lift inputs:

Units, exercise, weight lifted, reps, optional Wilks bodyweight and sex.
Estimated 1RM:

Dark panel with mean of Brzycki and Epley plus Save snapshot.
Wilks:

Appears when bodyweight is set; classic normalized score from estimated 1RM.
% of 1RM / Rep-max:

Two tables that refresh with every input change.

FAQ

How is estimated 1RM calculated on this page?

The dark Estimated 1RM readout is the rounded average of the Brzycki and Epley formulas from your weight and rep count. Brzycki uses

1RM = w / (1.0278 - 0.0278r)

; Epley uses

1RM = w(1 + r/30)

. Exercise choice labels your saved snapshot only; it does not change the math.

Which rep counts work best?

Formulas on this page clamp reps to 1–10 for the calculation. The field accepts up to 20, but if you enter more than 10 you will see an amber warning and the math runs as if you entered 10. For programming estimates, a hard set of about 3–8 reps with good form is the usual sweet spot.

What does the % of 1RM table show?

The % of 1RM table lists training weights from 95% down to 50% of your estimated max in the units you selected (kg or lb). Use it to pick working weights for percentage-based programs, for example 85% for heavy triples.

What is the Rep-max table?

The Rep-max (inverse Brzycki) table predicts the weight you could move for rep counts 2 through 12 if your estimated 1RM were exact. It applies the Brzycki relationship in reverse from the averaged 1RM, not a separate test.

When does the Wilks score appear?

Wilks shows when you enter a positive bodyweight and sex under the optional Wilks block. It uses the classic coefficient with your estimated 1RM in kg internally. Bodyweight does not change the 1RM estimate or the load tables.

What does Save snapshot do?

Save snapshot stores one result in your browser: exercise label, estimated 1RM (kg internally), and today's date. It appears below the button until you click Clear. Nothing is sent to a server.

Sources & citations

References used for the calculation method and definitions. Links open in a new tab when available.

[1]

Brzycki M. Strength testing—predicting a one-rep max from reps-to-fatigue. JOPERD. 1993;64(1):88-90

Source of the Brzycki 1RM prediction equation implemented in this calculator (denominator 1.0278 − 0.0278 × reps).

[2]

LeSuer DA et al. The accuracy of prediction equations for estimating 1-RM performance in the bench press, squat, and deadlift. J Strength Cond Res. 1997;11(4):211-213

Compares common 1RM prediction equations, including Epley-style models, against tested maxes in trained lifters.

Fitness Reference Note

Informational Use: These calculations (BMI, Calories, etc.) are based on standard statistical formulas and are intended for general reference and goal-setting purposes only.

Consult Experts: This tool does not provide medical advice, diagnosis, or treatment. Results may not be accurate for athletes, pregnant individuals, or those with underlying health conditions.

Health Safety: Always consult with a healthcare professional or qualified trainer before beginning any new diet or intensive exercise program.

Privacy First: All calculations are performed locally in your browser. No health data is stored or transmitted to any server.

Lift inputs

Wilks (optional)

Results

Wilks

% of 1RM

Rep-max (inverse Brzycki)