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How to Calculate Bench Press

What is Bench Press?

A bench press one-rep max (1RM) calculator estimates the maximum weight you could lift once based on a submaximal effort with known weight and reps. The most common formula is the Epley equation: 1RM = weight × (1 + reps/30).

Formula

Epley formula: 1RM = weight × (1 + reps/30)

Step-by-Step Guide

  1. 1Epley formula: 1RM = weight × (1 + reps/30)
  2. 2Brzycki formula: 1RM = weight × (36 / (37 − reps))
  3. 3More accurate with lower rep ranges (3–10 reps) — above 15 reps, accuracy decreases
  4. 4Percentage charts then help plan training loads (e.g., 80% 1RM for hypertrophy)

Worked Examples

Input
80kg for 8 reps
Result
1RM estimate: ~107kg
80 × (1 + 8/30) = 80 × 1.267 = 101.3 (Epley)
Input
100kg for 5 reps
Result
1RM estimate: ~117kg
100 × (1 + 5/30) = 116.7

Frequently Asked Questions

What is Bench Press?

A bench press one-rep max (1RM) calculator estimates the maximum weight you could lift once based on a submaximal effort with known weight and reps. The most common formula is the Epley equation: 1RM = weight × (1 + reps/30)

How accurate is the Bench Press calculator?

The calculator uses the standard published formula for bench press. Results are accurate to the precision of the inputs you provide. For financial, medical, or legal decisions, always verify with a qualified professional.

What units does the Bench Press calculator use?

This calculator works with inches, percentages. You can enter values in the units shown — the calculator handles all conversions internally.

What formula does the Bench Press calculator use?

The core formula is: Epley formula: 1RM = weight × (1 + reps/30). Each step in the calculation is shown so you can verify the result manually.

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