How to Calculate Your One Rep Max (1RM)

What Is Your Max?

Ever wondered what your “max” really is?
To be specific, we’re talking about the maximum weight you can lift for a single repetition—known in the gym world as your 1RM (One Rep Max).

How to Calculate Your 1RM

The most straightforward method is trying to lift the heaviest weight you can—just once.
But without experience or a spotter, this can be risky.

A safer approach is to lift a weight you believe you can manage for 3 to 5 reps, then use the following formula to estimate your 1RM:

1RM = lifted weight × reps × 0.033 + lifted weight

📌 Example: If you bench press 80 kg for 5 reps:
1RM = 80 × 5 × 0.033 + 80 = 93.2 kg

Alternatively, use an online 1RM calculator—they do the math for you in seconds.

Reps and Their Percentage of 1RM

Using the formula above and practical experience, we can estimate what percentage of your 1RM corresponds to certain rep ranges:

• 2 reps ≈ 94% of 1RM

• 3 reps ≈ 91%

• 5 reps ≈ 86%

• 10 reps ≈ 75%

This is incredibly useful when planning strength routines like 5×5 or 3×3, helping you choose the right weight for each training block.

Estimate how much weight you should lift for any rep range based on your One Rep Max using online calculator.

Individual Differences Matter

These are theoretical values, and real performance may differ.
Why? Because we’re all built differently—some people have more fast-twitch muscle fibers, others more slow-twitch. Neuromuscular efficiency and mental focus also play a role.

But that’s a topic for another time.