RM
calculator
Estimate your max (1RM) without risking a real test: enter the weight you moved and the reps you got, and the Brzycki formula does the rest.
Your 1RM from one set
Any set taken close to failure works (1 to 10 reps).
Bodyweight exercises
Pull-ups, dips and similar: the added weight for your 1RM and for a target percentage.
We use the Brzycki formula, the standard for estimating a 1RM without testing it: 1RM = weight ÷ (1.0278 − 0.0278 × reps). It gets more accurate the fewer reps the set has (ideally 6 or fewer) and the closer it is to failure.
Frequently asked questions
What is a 1RM?
The most weight you can move exactly once in an exercise with proper technique. It is the reference strength training is programmed on: plans prescribe percentages of that max.
How accurate is the estimate?
It is a reliable estimate for programming, not a lab test. With sets of 6 reps or fewer close to failure, the typical error is around 2-5%. More than enough to compute your working percentages.
What about bodyweight exercises?
Use the second calculator: it adds your body weight to the external load, estimates the total max and gives you back only the added weight, which is what you can adjust in the gym.
How often should I recalculate it?
Whenever your performance clearly changes. In Fishlimpia you do not have to: the app re-estimates your RM per exercise and per variation after every logged session.
Stop doing the math by hand
Fishlimpia stores your RM per exercise and variation and converts every percentage in the plan to kilos, session after session.
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