One Rep Max Calculator
Calculate your one rep max (1RM) from any weight and rep count. Uses Epley, Brzycki, and Lombardi formulas. Includes percentage table for programming.
Your one rep max (1RM) is the maximum weight you can lift for a single repetition. It's the foundation of all percentage-based strength programming — every training load in a powerlifting or strength programme is expressed as a percentage of 1RM. This calculator estimates it safely from a submaximal set.
Why Estimate Instead of Testing?
Actual 1RM testing requires maximum effort, significant warm-up time, and ideally a spotter. Testing regularly risks injury and fatigue. Estimating 1RM from a submaximal set (e.g., your 5-rep or 8-rep max) is safer, allows frequent updates, and is accurate within 2–5%.
1RM Formulas
Four validated formulas — each works slightly differently by rep range:
Epley (most commonly used, best for 1–10 reps):
1RM = Weight × (1 + Reps ÷ 30)
Brzycki (more accurate for higher reps):
1RM = Weight ÷ (1.0278 − 0.0278 × Reps)
Lombardi (conservative — lower estimate):
1RM = Weight × Reps^0.1
Mayhew (research-validated):
1RM = 100 × Weight ÷ (52.2 + 41.9 × e^(−0.055 × Reps))
Example — bench pressing 80 kg for 5 reps:
| Formula | Estimated 1RM |
|---|---|
| Epley | 80 × (1 + 5/30) = 93.3 kg |
| Brzycki | 80 ÷ (1.0278 − 0.0278×5) = 90.0 kg |
| Lombardi | 80 × 5^0.1 = 85.4 kg |
| Mayhew | ~89.5 kg |
The calculator uses the Epley formula as default (the most widely used in strength training software) and shows all four for comparison.
1RM Percentage Training Table
Once you know your 1RM, use this table to calculate your training loads:
| % of 1RM | For 1RM of 100 kg | Typical rep range | Training effect |
|---|---|---|---|
| 50% | 50 kg | 15–20 reps | Warm-up, technique |
| 60% | 60 kg | 12–15 reps | Endurance, hypertrophy (light) |
| 65% | 65 kg | 10–12 reps | Hypertrophy (moderate) |
| 70% | 70 kg | 8–10 reps | Hypertrophy |
| 75% | 75 kg | 6–8 reps | Hypertrophy / strength crossover |
| 80% | 80 kg | 4–6 reps | Strength |
| 85% | 85 kg | 3–5 reps | Strength |
| 90% | 90 kg | 1–3 reps | Max strength |
| 95% | 95 kg | 1–2 reps | Competition prep |
| 100% | 100 kg | 1 rep (true max) | Testing / competition |
Programming examples:
- 5×5 @ 80% 1RM — classic strength protocol (StrongLifts 5×5 style)
- 4×8 @ 70% 1RM — hypertrophy block
- 3×3 @ 90% 1RM — peaking week before competition
Strength Benchmarks by Body Weight
Squat
| Level | Men | Women |
|---|---|---|
| Beginner | 0.75× BW | 0.5× BW |
| Intermediate | 1.25× BW | 0.75× BW |
| Advanced | 1.75× BW | 1.25× BW |
| Elite | 2.5× BW | 1.75× BW |
Bench Press
| Level | Men | Women |
|---|---|---|
| Beginner | 0.5× BW | 0.35× BW |
| Intermediate | 0.75× BW | 0.5× BW |
| Advanced | 1.25× BW | 0.8× BW |
| Elite | 1.75× BW | 1.25× BW |
Deadlift
| Level | Men | Women |
|---|---|---|
| Beginner | 1.0× BW | 0.7× BW |
| Intermediate | 1.5× BW | 1.0× BW |
| Advanced | 2.0× BW | 1.5× BW |
| Elite | 2.75× BW | 2.0× BW |
Overhead Press
| Level | Men | Women |
|---|---|---|
| Beginner | 0.35× BW | 0.2× BW |
| Intermediate | 0.55× BW | 0.35× BW |
| Advanced | 0.8× BW | 0.55× BW |
| Elite | 1.1× BW | 0.75× BW |
When to Test Your 1RM
Do NOT test a true 1RM until:
- You have 3–6 months of consistent training on the lift
- Your form is solid at 90%+ of estimated 1RM
- You have a spotter for bench press and squat
- You are properly warmed up (work up in sets: 50%, 65%, 75%, 85%, 92%, 97%, attempt)
Update your estimated 1RM whenever your working weights increase significantly (every 4–8 weeks during active training).
Frequently Asked Questions
Which 1RM formula is most accurate?
For reps 1–5, all formulas give similar results. For reps 6–10, Brzycki and Mayhew tend to be more accurate than Epley. Above 10 reps, all estimates become less reliable — stick to 3–8 rep sets for best prediction accuracy. Epley is the most widely used in training apps and software.
Can I use this for any lift?
Yes — the formula applies equally to squat, bench press, deadlift, overhead press, row, and any other compound lift. It also applies to machine-based exercises. For isolation exercises (bicep curls, lateral raises), 1RM testing is less practically useful — these are typically trained by feel or for hypertrophy in 8–15 rep ranges.
What is RPE and how does it relate to 1RM?
RPE (Rate of Perceived Exertion) on a 1–10 scale is an alternative to percentage-based programming. RPE 10 = absolute maximum (1RM). RPE 9 = one rep in reserve. RPE 8 = two reps in reserve. Many modern powerlifting programmes use RPE instead of fixed percentages because it automatically accounts for daily variation in readiness. An RPE 8 at 80% 1RM on a good day might be RPE 9 on a fatigued day.
How often should I max out?
For most recreational lifters, true 1RM testing once per training cycle (8–16 weeks) is sufficient. Estimated 1RM updates can happen whenever you complete a new set at a higher weight. Frequent maxing increases injury risk and CNS fatigue without proportional strength gains.
What is the difference between 1RM and e1RM?
Technically, an estimated 1RM from a submaximal set is an e1RM. Your actual 1RM is what you can lift on that specific day in ideal conditions. The difference is usually 3–8% — some athletes consistently beat their e1RM estimates in competition; others fall short due to nervous system fatigue. The e1RM is more practically useful for programming.
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