One Rep Max Calculator
Estimated 1RM plus a full percentage training table.
Enter your values
Enter the weight lifted in lb.
Enter the reps completed you are working with.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Estimated 1RM
- 258 lb
- Epley formula
- 263 lb
- Brzycki formula
- 253 lb
| % of 1RM | Weight | Typical reps |
|---|---|---|
| 95% | 245 lb | 2 |
| 90% | 232 lb | 3 |
| 85% | 219 lb | 5 |
| 80% | 206 lb | 8 |
| 75% | 193 lb | 10 |
| 70% | 180 lb | 13 |
| 65% | 168 lb | 16 |
| 60% | 155 lb | 20 |
Quick answer
One rep max is the most weight you can lift once; the Epley formula estimates it as weight × (1 + reps/30).
1RM = weight × (1 + reps ÷ 30)
At a glance
| What it does | Estimated 1RM plus a full percentage training table. |
|---|---|
| Category | Health |
| Inputs needed | Weight lifted, Reps completed |
| Main output | Estimated 1RM |
| Formula | 1RM = weight × (1 + reps ÷ 30) |
| Cost | Free — no sign-up, no download |
How to use the One Rep Max Calculator
- 1Enter the weight you lifted.
- 2Enter how many clean reps you completed.
- 3Use the table to set training percentages.
Inputs explained
- Weight lifted(lb)
- Enter the weight lifted in lb.
- Reps completed
- Enter the reps completed you are working with.
Worked example
Using the values the calculator loads with:
Inputs
- Weight lifted225 lb
- Reps completed5
Results
- Estimated 1RM258 lb
- Epley formula263 lb
- Brzycki formula253 lb
Frequently asked questions
How accurate is a 1RM estimate?
Very accurate at 3–5 reps, less so above 8, where technique and conditioning start to dominate.
Should I test my true 1RM?
Rarely — estimates from a heavy triple carry most of the information at a fraction of the injury risk.
What do I need to enter into the One Rep Max Calculator?
Just 2 values: weight lifted, reps completed. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the One Rep Max Calculator work out the answer?
One rep max is the most weight you can lift once; the Epley formula estimates it as weight × (1 + reps/30). It applies the formula 1RM = weight × (1 + reps ÷ 30) and shows the working so you can check each step by hand.
Is the One Rep Max Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.