Calculate your one-rep max (1RM) using multiple proven formulas. Essential for strength training programs and tracking progress.
Last updated: March 2026 | By Patchworkr Team
Epley
93.3 kg
Brzycki
90 kg
Lander
91 kg
Lombardi
94 kg
| Program | %1RM | Rep Range | Goal |
|---|---|---|---|
| 5/3/1 Main Lifts | 85% | 3 reps | Pure strength |
| 5x5 / Strength | 82-85% | 5 reps | Strength + volume |
| Hypertrophy | 70-75% | 8-12 reps | Muscle growth |
| Accessory Work | 60-70% | 8-15 reps | Support main lifts |
| Deload Week | 50-60% | 5-8 reps | Recovery |
Note: Calculator estimates vary ±5% between formulas. For official 1RM testing, perform a maximal single rep with proper spotter. These estimates work best with 3-10 rep submaximal lifts.
| Program | %1RM | Rep Range | Goal |
|---|---|---|---|
| 5/3/1 Main Lifts | 85% | 3 reps | Pure strength |
| 5x5 / Strength | 82-85% | 5 reps | Strength + volume |
| Hypertrophy | 70-75% | 8-12 reps | Muscle growth |
| Accessory Work | 60-70% | 8-15 reps | Support main lifts |
| Deload Week | 50-60% | 5-8 reps | Recovery |
Note: Calculator estimates vary ±5% between formulas. For official 1RM testing, perform a maximal single rep with proper spotter. These estimates work best with 3-10 rep submaximal lifts.
A one-rep max (1RM) is the maximum weight you can lift for a single repetition with proper form. It's the gold standard for measuring absolute strength and is foundational to many strength training programs like 5/3/1, Texas Method, and Westside Barbell.
Rather than testing your 1RM directly (which carries injury risk and requires full recovery), this calculator uses validated formulas to estimate it from submaximal lifts. The Epley, Brzycki, Lander, and Lombardi formulas each use slightly different mathematical models based on research into the relationship between weight, reps, and max strength.
Most formulas work best with rep ranges of 1-10. Beyond 10 reps, predictions become less accurate as muscular endurance becomes a larger factor than pure strength. The calculator averages results from multiple formulas to give you a reliable estimate.
Step 1: Perform a warm set with a weight you can lift for 3-10 reps with good form. Push to technical failure (the point where form breaks down).
Step 2: Enter the weight you lifted and the number of reps you completed. Select your unit (kg or lb).
Step 3: Click "Calculate 1RM" to see your estimated one-rep max across four proven formulas.
Step 4: Use the training percentages table to plan your working sets. For example, 5×5 programs often use 80-85% of 1RM, while hypertrophy work uses 65-75%.
Scenario: You bench press 100 kg for 8 clean reps with no spotter assistance.
Weight
100 kg
Reps
8
Estimated 1RM:
Studies show Epley and Brzycki are most accurate for 1-10 reps. The calculator shows all four so you can average them for better reliability.
Test every 4-8 weeks during strength-focused training blocks. More frequent testing can interfere with recovery and progressive overload.
Yes! These formulas work for squat, deadlift, overhead press, and other compound movements. They're less accurate for isolation exercises.
Differences of 2-5% are normal. Use the average, or favor Epley/Brzycki for lower reps and Lombardi for higher reps (8-10).
Higher rep sets test muscular endurance more than max strength. Metabolic fatigue becomes the limiting factor rather than force production.
Yes. Round to the nearest 2.5 kg (5 lb) for practical loading. The percentages table does this automatically for training loads.
Different programs use different percentages: 5×5 (80-85%), hypertrophy (65-75%), speed work (50-60%), peaking (90-95%).
Your 1RM estimate will be higher than reality. Always use reps you can complete with proper form, stopping 1-2 reps before failure.
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