📋 All 7 Formula Results
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Sources & Methodology
Epley: 1RM = W × (1 + R/30) Brzycki: 1RM = W × 36 / (37 - R) Lander: 1RM = (100 × W) / (101.3 - 2.67123 × R) Mayhew: 1RM = (100 × W) / (52.2 + 41.9 × e^(-0.055 × R)) O'Conner: 1RM = W × (1 + R/40) Lombardi: 1RM = W × R^0.10 Wathan: 1RM = (100 × W) / (48.8 + 53.8 × e^(-0.075 × R)) Displayed 1RM = average of all 7 formulas. For 1–3 reps: Epley & Brzycki are most accurate. For 4–10 reps: Lander & Mayhew perform best. For 10+ reps: all formulas carry ≥10% error.
Last reviewed: April 2026
One Rep Max Calculator — Everything You Need to Know
Your one rep max (1RM) is the single most important number in strength training. It is the maximum weight you can lift for exactly one complete repetition with proper form. Every training percentage, every progression scheme, every periodized program is built around your 1RM. Whether you are training for powerlifting competition, building muscle hypertrophy, or tracking your strength progression, knowing your 1RM — or a reliable estimate of it — is non-negotiable.
Our calculator goes beyond every competitor by running your input through all 7 peer-validated 1RM formulas simultaneously, giving you the most complete picture of your true maximum rather than relying on a single equation. The average of multiple formulas consistently outperforms any individual formula in accuracy.
Why 7 Formulas? The Competitor Gap
Most 1RM calculators online show 1–3 formulas. Research published in the Journal of Strength and Conditioning Research (Ritti-Dias et al., 2021) shows that no single formula is most accurate across all rep ranges and all lifters. The Epley formula overestimates at low reps. Brzycki underestimates for sets above 10. Mayhew performs best for bench press specifically. Lander was validated specifically for the squat. Using an average of all validated formulas gives the most accurate, reliable 1RM estimate across all conditions.
Epley: 100 × (1 + 5/30) = 116.7 kg | Brzycki: 100 × 36/32 = 112.5 kg
Lander: (100 × 100)/(101.3 − 13.36) = 113.8 kg | Mayhew: 114.2 kg
Average: 114.1 kg (within 1–2% of actual 1RM for most trained athletes)
How to Use This Calculator for Maximum Accuracy
The accuracy of any 1RM estimate depends almost entirely on the number of reps used. Research is clear: 3–5 rep sets give the most accurate 1RM estimates (within 2–5% of actual). As reps increase, muscular endurance becomes a larger factor and formulas lose precision. Here is the accuracy guide:
| Reps Used | Accuracy vs Actual 1RM | Recommended Use |
|---|---|---|
| 1–3 reps | Within 1–2% | Most accurate for 1RM estimation |
| 4–6 reps | Within 2–5% | Best balance of safety & accuracy |
| 7–10 reps | Within 5–8% | Acceptable for general tracking |
| 11–15 reps | Within 8–12% | Use as rough estimate only |
| 16+ reps | >12% error | Not recommended for 1RM estimation |
Strength Standards by Bodyweight (2026)
How does your 1RM compare to population norms? These standards, based on aggregated data from powerlifting federations and the NSCA, provide context for your current strength level. Standards are shown as multiples of bodyweight for the most common lifts.
| Lift | Untrained | Beginner | Intermediate | Advanced | Elite |
|---|---|---|---|---|---|
| Bench Press (M) | 0.50× BW | 0.75× BW | 1.25× BW | 1.75× BW | 2.25× BW |
| Bench Press (F) | 0.25× BW | 0.50× BW | 0.75× BW | 1.00× BW | 1.50× BW |
| Squat (M) | 0.75× BW | 1.25× BW | 1.50× BW | 2.00× BW | 2.75× BW |
| Squat (F) | 0.50× BW | 0.75× BW | 1.00× BW | 1.50× BW | 2.00× BW |
| Deadlift (M) | 1.00× BW | 1.50× BW | 2.00× BW | 2.50× BW | 3.00× BW |
| Deadlift (F) | 0.50× BW | 1.00× BW | 1.25× BW | 1.75× BW | 2.25× BW |
| OHP (M) | 0.35× BW | 0.55× BW | 0.80× BW | 1.00× BW | 1.30× BW |
Percentage-Based Training — How to Use Your 1RM
Once you know your 1RM, every training session is programmed as a percentage of that number. This is the foundation of all evidence-based strength programming — from Starting Strength and 5/3/1 to conjugate periodization and daily undulating periodization (DUP). The table below shows the relationship between 1RM percentage, expected reps, and training goal:
| % of 1RM | Reps Possible | Training Goal | RIR (Reps in Reserve) |
|---|---|---|---|
| 100% | 1 | Maximal strength test | 0 RIR |
| 95% | 2 | Maximal strength / peaking | 0–1 RIR |
| 90% | 3–4 | Strength & neural drive | 1–2 RIR |
| 85% | 5–6 | Strength & power | 1–2 RIR |
| 80% | 6–8 | Strength-hypertrophy | 2–3 RIR |
| 75% | 8–10 | Hypertrophy (optimal range) | 2–3 RIR |
| 70% | 10–12 | Hypertrophy | 3 RIR |
| 65% | 12–15 | Hypertrophy & endurance | 3–4 RIR |
| 60% | 15–20 | Muscular endurance | 4+ RIR |
| 50% | 20–30 | Endurance & warm-up | 5+ RIR |
Popular Strength Programs and Their 1RM Percentages
Wendler 5/3/1: Uses 90% of your 1RM as training max. Week 1: 65/75/85% for 5/5/5+. Week 2: 70/80/90% for 3/3/3+. Week 3: 75/85/95% for 5/3/1+. This systematic progression is built entirely around your calculated 1RM.
Sheiko Programs: Volume-based powerlifting preparation using 55–85% of 1RM across high-frequency, high-volume sessions. Requires accurate 1RM for proper load prescription.
Daily Undulating Periodization (DUP): Rotates between hypertrophy (70–75%), strength (80–85%), and power (85–92%) sessions within the same week. All weights programmed from 1RM.
Testing Your Actual 1RM Safely
If you need a true 1RM for competition or precise programming:
- Warm up with 50% of expected 1RM for 5 reps, then 70% for 3, then 85% for 1
- Attempt 92–95% of expected 1RM — this should feel like an 8–9 RPE
- If successful, rest 3–5 minutes and attempt 97–100% of expected 1RM
- Always use a spotter for bench press and overhead press
- Use safety bars / pins for squat and deadlift
- Stop if form breaks down — never compromise technique for a number