One Rep Max Calculator
Calculate your max for any lift — fast. Use it to pick training weights without grinding a true 1RM.
Enter the weight you lifted, select your reps, and we’ll estimate your 1RM using the Brzycki formula.
Calculator
1-Rep Max:
See results →
Your 1RM updates instantly when you move the reps slider.
Formula: 1RM = weight × (36 / (37 − reps))
Results
Your estimated 1RM
Instant update as you change reps. Use the table to plan sets instead of guessing.
1-Rep Max:
253 lb
This is an estimate — it’s usually most accurate for low reps.
This is a common “heavy but repeatable” intensity for strength work.
1-RM Table
| Weight | Rep max | 1RM % |
|---|---|---|
| 253 lb | 1 rep | 100% |
| 240 lb | 2 reps | 95% |
| 235 lb | 3 reps | 93% |
| 228 lb | 4 reps | 90% |
| 220 lb | 5 reps | 87% |
| 215 lb | 6 reps | 85% |
| 210 lb | 7 reps | 83% |
| 203 lb | 8 reps | 80% |
| 195 lb | 9 reps | 77% |
| 190 lb | 10 reps | 75% |
| 185 lb | 11 reps | 73% |
| 177 lb | 12 reps | 70% |
What is One Rep Max (1RM)?
Your 1RM is the most weight you can lift for a single rep with solid form. It’s a useful reference point because it helps you choose training weights based on percentages instead of guessing.
Why you should not test 1RM often
True max attempts are stressful: they carry more injury risk, they create a lot of fatigue, and they don’t add much value for most people week to week. If you’re not competing, you rarely need to “prove” your max.
A better way to estimate strength
A safer approach is to use a 3–6 rep max (something heavy but controlled), then estimate your 1RM from that set. It’s usually close enough for programming and far easier to recover from.
How to use this calculator
- Enter the weight you lifted.
- Select how many reps you did (1–12).
- View your estimated 1RM.
- Use the table to pick training weights for different rep ranges.
How to use the 1RM table
The table shows what different percentages of your 1RM look like as actual training loads. A simple way to use it:
- 70–80%: great for hypertrophy (muscle building volume)
- 80–90%: strength-focused work
- 90%+: heavy, near-max effort
Why percentages matter
Percent-based loading helps you structure workouts and progress plans. It’s common in powerlifting and a lot of strength templates because it makes “hard” work repeatable without turning every day into a test day.
FAQ
Tip
For most people, the sweet spot is using a controlled set of 3–6 reps and letting the estimate guide the rest of training.
Reference page: fitnessstuffpod.com · Brzycki 1RM shown as \( weight × (36 / (37 − reps)) \).