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Estimate your one-rep maximum for any lift to gauge your strength and plan your training percentages.
Enter the weight and number of repetitions you successfully completed.
180.0 lbs
| % of 1RM | Weight |
|---|---|
| 95% | 171.0 lbs |
| 90% | 162.0 lbs |
| 85% | 153.0 lbs |
| 80% | 144.0 lbs |
| 75% | 135.0 lbs |
| 70% | 126.0 lbs |
| 65% | 117.0 lbs |
| 60% | 108.0 lbs |
| 55% | 99.0 lbs |
| 50% | 90.0 lbs |
Everything you need to know
Your One Repetition Maximum (1RM) is the maximum amount of weight you can lift for a single repetition of a given exercise with proper form. Knowing your 1RM is essential for designing effective strength training programs, tracking progress over time, and comparing your strength levels across different lifts.
Testing your actual 1RM through maximal lifts can be dangerous, time-consuming, and disruptive to your training. Our 1RM calculator estimates your maximum strength safely by using the weight and reps you can perform at submaximal intensities. This allows you to determine your training loads without the risks associated with true maximal testing.
Most strength programs prescribe weights as a percentage of your 1RM:
| Training Goal | Percentage of 1RM | Reps Per Set |
|---|---|---|
| Maximum strength | 85-100% | 1-5 reps |
| Strength and power | 75-85% | 3-6 reps |
| Hypertrophy (muscle growth) | 65-75% | 6-12 reps |
| Muscular endurance | 50-65% | 12-20+ reps |
Without knowing your 1RM, you are guessing at these percentages, which reduces the effectiveness of your program.
Testing your estimated 1RM every 4-8 weeks provides an objective measure of strength improvement. If your estimated bench press 1RM increases from 185 lbs to 205 lbs over three months, you have concrete evidence that your training is working.
Knowing your current 1RM helps you set achievable short-term and long-term strength targets. A beginner male might aim for a 225-pound bench press, while an advanced lifter might target 315 pounds or more.
Your 1RM allows you to compare strength across different exercises and against established strength standards.
Our calculator uses three well-established formulas and averages the results for improved accuracy:
1RM = Weight × (1 + Reps ÷ 30)
This formula tends to be more accurate for higher rep ranges (8-12 reps).
Example: 185 lbs for 8 reps 1RM = 185 × (1 + 8 ÷ 30) = 185 × 1.267 = 234 lbs
1RM = Weight ÷ (1.0278 - 0.0278 × Reps)
This formula is widely used by strength coaches and tends to be accurate for moderate rep ranges (4-10 reps).
Example: 185 lbs for 8 reps 1RM = 185 ÷ (1.0278 - 0.0278 × 8) = 185 ÷ 0.8054 = 230 lbs
1RM = Weight × Reps^0.10
This formula works well across a broad range of rep ranges.
Example: 185 lbs for 8 reps 1RM = 185 × 8^0.10 = 185 × 1.232 = 228 lbs
Using all three formulas: (234 + 230 + 228) ÷ 3 = 231 lbs
The accuracy of 1RM prediction depends heavily on the rep range used:
| Rep Range Used | Accuracy | Best For |
|---|---|---|
| 1-3 reps | Very high (±2-3%) | Powerlifters, strength athletes |
| 4-6 reps | High (±3-5%) | Most lifters, general strength |
| 7-10 reps | Moderate (±5-8%) | Bodybuilders, recreational lifters |
| 11-15 reps | Lower (±8-12%) | Endurance-focused athletes |
| 15+ reps | Low (±12-20%) | Not recommended for 1RM estimation |
Recommendation: For the most accurate 1RM estimate, use a weight you can lift for 3-8 reps with good form, stopping 1-2 reps before failure.
| Level | Men (lbs) | Women (lbs) |
|---|---|---|
| Untrained | 135 | 65 |
| Beginner | 175 | 90 |
| Intermediate | 215 | 115 |
| Advanced | 290 | 155 |
| Elite | 350+ | 195+ |
Standards for a 165 lb man and 125 lb woman. Adjust proportionally for different body weights.
| Level | Men (lbs) | Women (lbs) |
|---|---|---|
| Untrained | 145 | 70 |
| Beginner | 205 | 100 |
| Intermediate | 265 | 135 |
| Advanced | 355 | 185 |
| Elite | 445+ | 230+ |
| Level | Men (lbs) | Women (lbs) |
|---|---|---|
| Untrained | 175 | 85 |
| Beginner | 240 | 120 |
| Intermediate | 315 | 160 |
| Advanced | 405 | 210 |
| Elite | 505+ | 265+ |
To build strength, you must gradually increase the demands placed on your muscles. Common methods include:
| Phase | Weeks | Percentage of 1RM | Focus |
|---|---|---|---|
| Hypertrophy | 1-4 | 65-75% | Build muscle mass |
| Strength | 5-8 | 75-85% | Build maximal strength |
| Peaking | 9-11 | 85-95% | Prepare for max attempt |
| Deload | 12 | 50-60% | Recovery and adaptation |
True 1RM testing is highly fatiguing and increases injury risk. Limit actual max attempts to once every 8-12 weeks. Use estimated 1RM for programming between tests.
Estimating 1RM from a 20-rep set produces unreliable results. Always use 10 reps or fewer for estimation.
If your last rep looked ugly — back rounded, knees caving, bar path drifting — that set should not be used for 1RM estimation. Good form is essential for both safety and accuracy.
Your 1RM on a barbell back squat does not translate to a leg press or hack squat. Each exercise has its own 1RM.
Strength standards are relative to body weight. A 150-pound person deadlifting 300 pounds (2x body weight) is stronger relative to their size than a 250-pound person deadlifting 400 pounds (1.6x body weight).
For most lifters, once every 8-12 weeks is sufficient. Powerlifters may test more frequently before competitions.
Yes, but beginners should focus on learning proper form with lighter weights before worrying about maximal strength. After 2-3 months of consistent training, 1RM data becomes useful.
Each formula was developed from different populations and rep ranges. Averaging multiple formulas provides the best estimate. Epley tends to overestimate at high reps; Brzycki tends to underestimate.
Yes. Most people are 5-10% stronger in the afternoon and evening compared to early morning due to body temperature, hormone levels, and nervous system readiness.
No. Focus on compound lifts: squat, bench press, deadlift, overhead press, and row. Isolation exercises are rarely tested for 1RM.