One-Rep Max (1RM) Calculator
Estimate your 1RM from any submaximal lift. Uses Epley, Brzycki, and Lombardi formulas. Includes a full training percentage table for strength programming.
Added May 26, 2026
Input
Result
Enter a value for weight lifted to see your result.
How it works
Estimate your one-rep max (1RM) from a submaximal lift using the Epley, Brzycki, and Lombardi formulas. See a full training percentage table showing recommended weights for strength, hypertrophy, and endurance zones.
Step by step
- 01Enter the weight you lifted and select kg or lbs.
- 02Enter how many reps you completed — ideally between 3 and 10 for the most accurate estimate.
- 03The calculator runs three established formulas (Epley, Brzycki, Lombardi) and averages them.
- 04Use the training percentage table to plan your working sets at any intensity zone.
Examples
100 kg × 5 reps bench press
If you bench 100 kg for 5 reps, your estimated 1RM is ~116 kg. This means your 80% training weight is ~93 kg — use the percentage table for the full breakdown.
Inputs
- Weight lifted:
- 100
- Unit:
- kg
- Reps performed (1–20):
- 5
Result
- Estimated 1RM (average):
- ~116 kg
- Epley formula:
- 116.7 kg
Frequently asked questions
What is one-rep max (1RM)?
Your one-rep max (1RM) is the maximum weight you can lift for a single repetition with good form. It's used in strength training to set training intensities as a percentage of 1RM — for example, 80% 1RM for 5×5 strength work or 65% for higher-rep hypertrophy sets.
Which 1RM formula is most accurate?
Brzycki is generally considered most accurate for 1–6 rep ranges. Epley tends to overestimate slightly at higher rep counts. For 1–3 reps, all three formulas are close. For 8+ reps, the Lombardi formula is often cited as more reliable. Averaging the three reduces formula-specific bias.
Is it safe to test my true 1RM?
A true 1RM test should only be attempted when well-rested, properly warmed up, and with an experienced spotter. Many coaches prefer to estimate 1RM from submaximal work rather than risk injury with a max single. This calculator gives you that estimate without the risk.
How do I use 1RM percentages in training?
Common percentage zones: 90–100% (max strength, 1–3 reps), 80–90% (strength, 3–5 reps), 67–80% (hypertrophy, 6–12 reps), below 67% (endurance, 15+ reps). Most periodized programs prescribe work as a percentage of 1RM to auto-regulate training load.