One rep max calculator (1RM)

Enter a weight and how many clean reps you did. You get your estimated one rep max from Epley, Brzycki and Lombardi, and a percentage chart for planning sets — no risky max attempt needed.

Standard

Defaults to your region. Switch to compare any other scale.

Weight lifted

Repetitions done (1–12 for best accuracy)

Unit

Formula for the main result

Result

116 lb

Estimated one rep max (1RM)

Epley117 lb
Brzycki113 lb
Lombardi117 lb
Average of all three116 lb

Estimate, not a tested max

Use the % table to plan sets: about 85–95% for strength, 67–85% for hypertrophy. Warm up properly and use a spotter for heavy attempts. Not medical advice.

Training loads by % of 1RM

% of 1RM	Load	≈ Reps
100%	116 lb	1
95%	110 lb	2
90%	104 lb	3
85%	98 lb	5
80%	92 lb	8
75%	87 lb	10
70%	81 lb	13
65%	75 lb	16
60%	69 lb	20
55%	64 lb	25
50%	58 lb	30

About this tool

What is a one rep max?

Your one rep max (1RM) is the heaviest weight you can lift once with good form in an exercise such as the bench press, squat or deadlift. Programs prescribe loads as a percentage of 1RM, so knowing it helps you train at the right intensity.

1RM formulas

Epley: 1RM = w × (1 + r ÷ 30). Brzycki: 1RM = w × 36 ÷ (37 − r). Lombardi: 1RM = w × r^0.10. Here w is the weight lifted and r the number of reps. All three agree closely between 2 and 10 reps; Brzycki is slightly more conservative.

Worked example

You bench 100 kg for 5 reps. Epley: 100 × (1 + 5 ÷ 30) = 117 kg. Brzycki: 100 × 36 ÷ 32 = 113 kg (112.5). Lombardi: 100 × 5^0.10 = 117 kg. Average ≈ 115 kg, so 80% for sets of about 8 would be ≈ 93 kg.

Safety

These are estimates. Warm up, progress gradually and use a spotter or safety bars for heavy lifts. This page is not medical advice.

Formula

Epley: 1RM = w × (1 + r ÷ 30)
Brzycki: 1RM = w × 36 ÷ (37 − r)
Lombardi: 1RM = w × r^0.10
Load at p% = 1RM × p ÷ 100

How it is calculated

Do a set with good form close to failure and note the weight and reps.
Enter the weight, the reps and the unit (kg or lb).
Pick Epley, Brzycki, Lombardi or the average for the main result.
Use the percentage table to choose weights for your next sets.

Questions

How do I calculate my one rep max?

Lift a weight for as many clean reps as you can (ideally 3–8), then apply a formula. With Epley, 100 kg × 5 reps gives 100 × (1 + 5 ÷ 30) ≈ 117 kg.

Which 1RM formula is most accurate?

No single formula wins for everyone. Brzycki tends to be accurate below 10 reps, Epley slightly higher for 5–10 reps, and Lombardi is gentler at high reps. The average of all three is a sensible middle ground.

What percentage of my 1RM should I train with?

Roughly 85–95% for 1–5 reps (strength), 67–85% for 6–12 reps (muscle growth) and below 67% for 15+ reps (endurance). The table on this page shows the load and approximate reps for each percentage.

Is it safe to test a real 1RM?

It can be for experienced lifters with a spotter and good technique, but it carries more injury risk. Beginners should rely on a calculated estimate from 3–8 reps instead.