Question 1

Which 1RM formula is most accurate?

Accepted Answer

No single formula is universally most accurate. For 1–5 rep sets, Epley (1985) and Brzycki (1993) perform similarly well (±3–5%). For 6–10 reps, Mayhew (1992) and Wathen (1994) tend to outperform. Above 10 reps, accuracy drops significantly for all formulas. Our consensus approach uses the median of all six to reduce individual formula variance.

Question 2

What is the Epley 1RM formula?

Accepted Answer

The Epley formula (1985) is: 1RM = weight × (1 + reps / 30). It is the most commonly used 1RM prediction equation due to its simplicity and accuracy across a range of rep counts. For example, 100 kg × 5 reps → 1RM = 100 × 1.167 = 116.7 kg.

Question 3

What are the NSCA strength standards for squat, bench press, and deadlift?

Accepted Answer

NSCA strength standards (Baechle & Earle 2008) classify lifters as Untrained, Novice, Intermediate, Advanced, or Elite based on 1RM relative to bodyweight. For example, a male intermediate squatter should reach 1.50× bodyweight, bench press 1.10×, and deadlift 1.75×. Female thresholds are approximately 65–75% of male values.

Question 4

What is the Wilks score and how is it calculated?

Accepted Answer

The Wilks score normalises powerlifting totals across bodyweights. Wilks = coefficient × lifted weight, where the coefficient is derived from a 5th-degree polynomial based on bodyweight and sex (Wilks 1998). A score of 300+ indicates club competitor level; 400+ is state/regional; 500+ is elite. IPF GL points (Taber 2020) replaced Wilks in IPF-sanctioned competition in 2019.

Question 5

What is RPE in strength training and how does the RPE-based 1RM work?

Accepted Answer

RPE (Rating of Perceived Exertion) on a 6–10 scale quantifies how close a set is to failure. RIR (Reps In Reserve) = 10 − RPE. The Helms (2016) e1RM formula is: e1RM = weight × (1 + (reps + RIR) / 30). This accounts for daily readiness unlike Epley, which assumes reps were taken to failure. RPE 8 = 2 RIR — the recommended training zone for strength and hypertrophy.

Question 6

What are ideal Squat:Bench:Deadlift ratios?

Accepted Answer

Evidence-based balance ratios: Bench should be approximately 0.67× Squat (Bench:Squat ratio ≈ 0.67). Deadlift should be approximately 1.20× Squat (DL:Squat ratio ≈ 1.20). Deviations >15% from these targets indicate a relative weakness. These ratios derive from competitive powerlifting population norms and are applicable to raw/classic lifting.

Question 7

How do I use percentage of 1RM for training?

Accepted Answer

NSCA/ACSM guidelines (2016): Maximal Strength = 85–100% 1RM for 1–5 reps; Power = 75–90% for 1–5 reps with speed emphasis; Hypertrophy = 65–85% for 6–12 reps; Muscular Endurance = 50–70% for 12–20 reps. Beginners should use the lower end of each range; advanced lifters can use the upper end. Re-test 1RM every 8–12 weeks to update loads.

Question 8

How often should I re-test my 1RM?

Accepted Answer

Practical recommendation: beginners progress rapidly and should re-test every 4–6 weeks. Intermediate lifters every 6–8 weeks. Advanced/elite lifters every 10–16 weeks. Re-testing too frequently wastes training time and increases injury risk. Using a planned 5-rep max set to update estimates is safer and more training-efficient than true 1RM attempts.

Question 9

Is the one-rep max calculator accurate for beginners?

Accepted Answer

Prediction accuracy decreases for beginners because they have not yet developed the technique consistency and neural efficiency needed for maximal single-rep efforts. 1RM equations are validated primarily on intermediate-to-advanced trainees. Beginners typically show 5–15% overprediction at the 1RM when calculated from sets of 10+ reps. Use 3–5 rep sets for better beginner accuracy.

Type	Description
All Formulas	Compare Epley, Brzycki, Lombardi
Epley Formula	w × (1 + r/30)
Brzycki Formula	w × 36/(37-r)

Type	Description
All Formulas	Compare Epley, Brzycki, Lombardi
Epley Formula	w × (1 + r/30)
Brzycki Formula	w × 36/(37-r)

One-Rep Max: Guide

What is 1RM?

Formulas

Tips

How to Use

Real-World Applications

FAQs

Are the results accurate?

Why does a small input change affect the output significantly?

Other Health & Fitness Calculators