What Is the Percentage of 1RM Calculator?
Strength programs are usually written as a percentage of your one-rep max (1RM) — the heaviest weight you can lift for a single clean repetition. A program might call for "5 sets of 3 at 80%." This calculator converts those percentages into the exact load to put on the bar, so you can stop doing mental math between sets.
How to Use It
Enter your current 1RM for a given lift (bench, squat, deadlift, overhead press, etc.) in whatever unit you train with — kilograms or pounds. Then enter the target percentage from your program. The calculator returns your working weight, plus a quick reference table showing the loads at 50%, 60%, 70%, 80% and 90% so you can plan an entire session at a glance.
The Formula Explained
The math is simple and unit-agnostic:
$$\text{Working Weight} = \text{1RM} \times \frac{\text{Percentage (\%)}}{100}$$
Because it's a direct proportion, the same formula works whether you train in kg or lb — the output is in the same unit you entered. For practical lifting, round to the nearest plate increment your gym offers (often 2.5 kg or 5 lb).
Worked Example
Suppose your bench-press 1RM is 100 kg and your program prescribes 80%. $$\text{Working Weight} = 100 \times \frac{80}{100} = 100 \times 0.8 = \textbf{80 kg}$$ If the next block drops to 70%, you'd load 70 kg instead.
FAQ
How do I find my 1RM? Either test it directly with a true single-rep max attempt, or estimate it from a set you've done (e.g. a weight you lifted for 5 reps) using a 1RM estimation calculator.
Should I round the result? Yes — round to the smallest plate jump available so the bar is loadable. Rounding down a kilogram or two is usually fine.
Does it work for any lift? Yes. The percentage relationship applies to any barbell or dumbbell lift, though percentages may feel slightly different across exercises.
