CalKit

One Rep Max Calculator

Estimate your one-rep max (1RM) from weight and reps.

kg
회
예상 1RM
90kg

Brzycki 공식 기반

무게 퍼센트 테이블

100% (1RM)90 kg
95% (1-3회)86 kg
90% (1-3회)81 kg
85% (4-6회)77 kg
80% (4-6회)72 kg
75% (8-10회)68 kg
70% (8-10회)63 kg
65% (12-15회)59 kg
60% (12-15회)54 kg
50% (20회+)45 kg

Overview

Estimate your one-rep max (1RM) from the weight lifted and the number of repetitions performed. This calculator uses the Epley formula as the primary method, with Brzycki and Lander formulas available for comparison. Essential for designing weight training programs and managing intensity.

Formula

Epley Formula: 1RM = Weight × (1 + Reps ÷ 30)
Brzycki Formula: 1RM = Weight × 36 ÷ (37 − Reps)
Lander Formula: 1RM = 100 × Weight ÷ (101.3 − 2.67123 × Reps)

%1RM Training Zones:
• 1–3 reps (90–100%): Maximal Strength
• 4–6 reps (80–90%): Strength/Hypertrophy
• 8–12 reps (65–80%): Hypertrophy
• 15+ reps (≤65%): Muscular Endurance

How to Use

  1. 1Enter the weight lifted in kg (e.g., 80 kg).
  2. 2Enter the number of reps completed with that weight (e.g., 8 reps).
  3. 3Your estimated 1RM is calculated automatically using the Epley formula.
  4. 4A breakdown of weights at each %1RM with recommended rep ranges is also displayed.

Tips

  • ✔The Epley formula is most accurate for rep counts of 10 or fewer.
  • ✔Avoid actual 1RM testing due to injury risk — use calculated estimates instead.
  • ✔Your 1RM can fluctuate daily based on sleep, nutrition, and stress.
  • ✔Set your 'training max' at 90% of estimated 1RM for safer programming.
  • ✔Results are most accurate for compound lifts (squat, deadlift, bench press).

FAQ

Q. Is the Epley or Brzycki formula more accurate?

Both formulas produce similar results at low rep ranges (1–6 reps). At higher rep counts (10+), the Epley formula tends to slightly overestimate. The Epley formula is the most widely used; averaging both formulas is also a valid approach.

Q. Should I test my actual 1RM?

Direct testing is the most accurate but carries significant injury risk, especially for beginners or those training alone. Use estimated formulas instead. If you do test directly, always have a spotter, warm up thoroughly, and increase weight gradually.

Q. How often should I re-test my 1RM?

Re-test every 4–6 weeks, ideally at the end of a training cycle. Beginners who gain strength quickly may re-test every 3–4 weeks, while advanced lifters can wait 6–8 weeks between tests.

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