Question 1

What is a one rep max (1RM)?

Accepted Answer

A one rep max (1RM) is the maximum amount of weight you can lift for a single repetition of a given exercise with proper form. It is the gold standard measure of maximal strength and is used by strength coaches, powerlifters, and fitness professionals to program training intensities. Rather than actually testing your 1RM (which carries injury risk), you can estimate it from a submaximal set using formulas like Epley and Brzycki.

Question 2

Which formula is more accurate, Epley or Brzycki?

Accepted Answer

Research shows both formulas are similarly accurate for 1-10 rep ranges, with differences typically less than 2-3%. The Epley formula tends to produce slightly higher estimates at higher rep ranges (8+), while the Brzycki formula is often preferred for lower rep ranges (3-6). By averaging both, this calculator provides a more reliable estimate. For the most accurate result, use a weight you can lift for 3-5 reps with proper form.

Question 3

How do I use the percentage table for training?

Accepted Answer

The percentage table translates your 1RM into training loads for different rep ranges. For strength (1-5 reps), train at 85-100% of 1RM. For hypertrophy/muscle building (6-12 reps), train at 65-85%. For muscular endurance (12-15+ reps), train at 60-70%. For example, if your 1RM squat is 100kg, a hypertrophy set of 8 reps would use approximately 80kg (80% of 1RM).

Question 4

How often should I test or recalculate my 1RM?

Accepted Answer

Recalculate every 4-8 weeks during a structured training programme, or whenever you complete a training cycle. Beginners may see 1RM improvements every 2-4 weeks, while intermediate lifters may progress every 4-8 weeks, and advanced lifters every 8-12 weeks. Using the calculator with a recent submaximal set (e.g., your best 5-rep set from this week) is safer and more practical than actually testing a true 1RM regularly.

Question 5

Why is my estimate less accurate with higher reps?

Accepted Answer

Both formulas were validated primarily with 1-10 rep sets. As reps increase beyond 10, factors like muscular endurance, cardiovascular fitness, pain tolerance, and mental fatigue become larger variables that the formulas do not account for. A set of 20 reps involves significant aerobic and endurance components that are unrelated to maximal strength. For the best estimate, use a weight you can lift for 3-6 reps with good form and full effort.

Question 6

Is testing your actual 1RM dangerous?

Accepted Answer

Testing a true 1RM carries higher injury risk than normal training because you are handling maximal loads. However, it can be done safely with proper preparation: warm up thoroughly, use a spotter or safety bars, choose exercises with safe failure modes (e.g., squat with safety pins), build up gradually in 5-10% increments, and only attempt it when fresh and healthy. Most recreational lifters can get everything they need from estimated 1RM calculations without ever testing maximally.

Question 7

Does 1RM differ between exercises?

Accepted Answer

Yes, dramatically. Your 1RM for a back squat will be very different from your bench press or deadlift 1RM. Common strength ratios for intermediate male lifters are roughly: deadlift 1RM is highest, squat is about 80-85% of deadlift, bench press is about 60-70% of deadlift, and overhead press is about 40-50% of deadlift. These ratios vary by individual body proportions, training history, and muscle group strengths. Calculate 1RM separately for each exercise.

One Rep Max Calculator — Estimate Your 1RM