About One Rep Max Calculator
Our One Rep Max (1RM) Calculator is a professional strength training tool that estimates your maximum lifting capacity using 7 scientifically validated formulas. Whether you're a powerlifter, bodybuilder, CrossFit athlete, or general fitness enthusiast, this calculator provides accurate 1RM estimates without the risk and fatigue of actual max testing.
Simply enter the weight you lifted and how many reps you completed, and our calculator will provide your estimated 1RM using Epley, Brzycki, Lander, Lombardi, Mayhew, O'Conner, and Wathan formulas. You'll also receive a complete training plan with 9 percentage zones (50-95%) optimized for different training goals: maximum strength, power, hypertrophy, and muscular endurance.
Understanding One Rep Max
What is 1RM?
One Repetition Maximum (1RM) is the maximum amount of weight you can lift for exactly one complete repetition with proper form. It's the gold standard measurement of maximum strength in resistance training.
Why 1RM Matters
- Measures Absolute Strength: Provides an objective number for your maximum force production.
- Programs Training: Allows percentage-based programming (e.g., 80% of 1RM for 5 reps).
- Tracks Progress: Quarterly 1RM testing shows if your training is working.
- Sets Goals: Provides clear targets (e.g., "reach 2x bodyweight squat").
- Compares Lifters: Bodyweight ratios allow fair comparison across weight classes.
Calculator vs. Actual Testing
Most athletes should use calculators for regular training and only test actual 1RM 2-4 times per year. Here's why:
✅ Calculator Benefits
- • Much safer (no injury risk)
- • Can test frequently (weekly)
- • Less fatiguing (use 80-85% weight)
- • No spotter needed
- • Better for programming
⚠️ Actual Testing
- • High injury risk
- • Needs 5-7 days recovery
- • Requires spotter/safety equipment
- • Only useful 2-4x per year
- • Needed for competition
1RM Calculation Formulas
Our calculator uses 7 validated formulas. Each has different mathematical approaches and works best for specific rep ranges:
1. Epley Formula (1985) ⭐ Most Popular
1RM = Weight × (1 + Reps / 30)
Best for: 1-6 reps. Slightly optimistic but widely used in powerlifting.
2. Brzycki Formula (1993) ⭐ Best for High Reps
1RM = Weight × (36 / (37 - Reps))
Best for: 7-12 reps. More conservative, preferred by many coaches.
3-7. Other Formulas
Lander, Lombardi, Mayhew, O'Conner, and Wathan provide additional estimates. Our calculator shows all 7 and provides an average for balanced programming.
📊 Accuracy by Rep Range
- • 1-3 reps: ±3-5% (highly accurate)
- • 4-6 reps: ±5-8% (very good, recommended)
- • 7-10 reps: ±8-12% (moderate)
- • 11-15 reps: ±15-20% (less reliable)
Training with Percentages
Once you know your 1RM, use percentage-based training to optimize for different goals:
| % of 1RM | Reps | Training Goal | Rest Time |
|---|---|---|---|
| 95% | 1-2 | Max strength / Competition | 5 min |
| 90% | 2-3 | Max strength / Peaking | 4-5 min |
| 85% | 3-5 | Strength training | 3-4 min |
| 80% | 5-6 | Strength / Power | 2-3 min |
| 75% | 6-8 | Hypertrophy (muscle growth) | 2-3 min |
| 70% | 8-10 | Hypertrophy / Endurance | 2 min |
| 65% | 10-12 | Muscular endurance | 1-2 min |
| 60% | 12-15 | Endurance / Warm-up | 1 min |
| 50% | 15-20 | Warm-up / Recovery | 30s-1 min |
Sample Training Week
- Monday (Strength Day): 85% × 5 reps, 5 sets, 3-4 min rest
- Wednesday (Hypertrophy Day): 75% × 8 reps, 4 sets, 2-3 min rest
- Friday (Volume Day): 70% × 10 reps, 3-4 sets, 2 min rest
Deload every 4-6 weeks: Drop to 60-70% for one week to allow full recovery.
Strength Standards
Strength standards compare your 1RM to your bodyweight. Here are general population standards for adult males:
| Level | Bench Press | Squat | Deadlift | OHP |
|---|---|---|---|---|
| Beginner | 0.5x BW | 0.75x BW | 1.0x BW | 0.35x BW |
| Novice | 0.75x BW | 1.0x BW | 1.25x BW | 0.5x BW |
| Intermediate | 1.0x BW | 1.5x BW | 1.75x BW | 0.75x BW |
| Advanced | 1.5x BW | 2.0x BW | 2.5x BW | 1.0x BW |
| Elite | 2.0x+ BW | 2.5x+ BW | 3.0x+ BW | 1.5x+ BW |
Note: Female standards are typically 60-70% of male standards. These are general population standards, not competitive powerlifting requirements.
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Additional Resources
For more information about strength training and 1RM: