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One Rep Max Calculator
Estimate your 1RM for bench press, squat, deadlift or any lift in seconds. Get instant training percentages and compare formulas to plan your next session.
Enter your lift
Your estimated one rep max
Bench Press · estimated 1RM
115.0 kg
Raw estimate: 115.5 kg · 254.7 lb
Epley
116.7 kg
Brzycki
112.5 kg
Lombardi
117.5 kg
Training percentages
| % | Weight | Reps |
|---|---|---|
| 100% | 115.5 kg | 1 rep |
| 95% | 109.8 kg | 1-2 reps |
| 90% | 104.0 kg | 2-3 reps |
| 85% | 98.2 kg | 3-5 reps |
| 80% | 92.4 kg | 4-6 reps |
| 75% | 86.7 kg | 6-8 reps |
| 70% | 80.9 kg | 8-10 reps |
| 65% | 75.1 kg | 10-12 reps |
| 60% | 69.3 kg | 12-15 reps |
| 50% | 57.8 kg | 15-20 reps |
| 40% | 46.2 kg | 20+ reps |
Estimated weight for 1–12 reps
1 rep
115.5 kg
2 reps
108.3 kg
3 reps
105.0 kg
4 reps
101.9 kg
5 reps
99.0 kg
6 reps
96.3 kg
7 reps
93.7 kg
8 reps
91.2 kg
9 reps
88.9 kg
10 reps
86.7 kg
11 reps
84.5 kg
12 reps
82.5 kg
Jump to your lift
Each lift has its own standards, technique notes and percentage guidance.
How to calculate your one rep max
You don't need to lift a true maximal weight to know your one rep max. Instead, perform a set of 1-10 reps with good form, taken close to failure (within 1-2 reps in reserve), and let a formula estimate the heaviest weight you could lift once.
Enter the weight you lifted and the number of reps you completed into the calculator above. MaxRep runs your numbers through three validated formulas — Epley, Brzycki and Lombardi — and averages them by default so no single formula's bias skews your estimate. You can also select a single formula manually.
Once you have your 1RM, the training percentage table shows exactly what weight to load for strength, hypertrophy or technique work — no mental math required.
Epley vs. Brzycki formulas
Epley formula
1RM = weight × (1 + reps ÷ 30)
Simple and widely used. Tends to run slightly higher on sets above 10 reps. Learn more →
Brzycki formula
1RM = weight × 36 ÷ (37 − reps)
Most accurate for sets under 10 reps; diverges quickly above that range. Learn more →
Using 1RM to plan training
Programs are usually written as a percentage of your 1RM — for example "work up to 5 reps at 80%". Once your estimated max is set, you can plan every session off it: lighter percentages (50-65%) for warm-ups and technique, moderate percentages (65-80%) for hypertrophy, and heavier percentages (80-95%) for strength and peaking. Recalculate your training percentages as you get stronger.
Frequently asked questions
What is a one rep max (1RM)?+
Your one rep max is the heaviest weight you can lift for a single, complete repetition with good form. It's the standard way lifters measure and compare raw strength.
How accurate is an estimated 1RM?+
Formula-based estimates are typically within 5-10% of your true max when you use a set of 1-10 reps taken close to failure. Accuracy drops for very high rep sets, so for the most precise number, test with a low rep set (1-5 reps) or do a supervised max attempt.
Which formula should I use: Epley or Brzycki?+
Epley tends to estimate slightly higher for higher rep sets, while Brzycki is tuned for sets under 10 reps. We default to an average of Epley, Brzycki and Lombardi so no single formula's bias skews your number, but you can switch to any formula manually.
Do I need to create an account to use the calculator?+
No. The 1RM calculator, unit conversion, formulas and percentage tables are completely free and don't require sign in. No account is needed to use these tools.
Is it safe to test my real one rep max?+
Testing a true 1RM carries injury risk, especially without a spotter or coach. Most lifters only need to test a handful of times per year. Use this calculator to estimate your max from a set you already performed and save the real test for when you have a spotter and have properly warmed up.
How often should I retest my 1RM?+
Every 4-8 weeks is plenty for most training programs. Re-estimating too often adds fatigue without giving your program time to produce results. Use consistent exercise technique when comparing estimates over time.
Safety disclaimer
MaxRep's calculators provide estimates for training purposes only and are not a substitute for professional coaching or medical advice. Always warm up thoroughly, use a spotter or safety bars for heavy attempts, and consult a qualified professional before starting any new training program. See our full disclaimer.