Enter one hard set
Use the total load, including the bar, and count completed reps. A set between 1 and 10 reps gives the clearest estimate. More than 10 reps is reduced to a 10RM first, then projected to a 1RM.
One Rep Max (1RM) Calculator
Calculate your one-rep max (1RM) for any exercise. One-rep max is the max weight you can lift for a single repetition for a given exercise.
Your one rep max is: --
Based on your working set.
| Percentage of 1RM | Lift Weight | Repetitions of 1RM |
|---|
Use this as a training estimate. Use a spotter or safety pins for heavy work.
FREE WORKOUT TRACKER Track your progress in IroniA simple 1RM calculator with useful context
An estimated one-rep max gives you a practical training number without asking you to test a true maximum every week. This 1RM calculator turns one hard set into an estimate of the heaviest load you could lift once with good technique. Enter weight, reps, and kilograms or pounds. A percentage table helps plan back-off work, compare sessions, or choose a top set.
Read the estimate
Your answer stays in the unit you selected. The table maps it to common percentages, from 100% for one rep to lighter work for higher repetitions.
Train with judgment
A formula cannot see your technique, fatigue, sleep, or equipment. Use the number to guide a session, then adjust the load when bar speed or form says you should.
Bench, squat, deadlift, and pull-up estimates
Whether you call it a bench 1RM calculator or a 1RM calculator bench, the inputs stay the same. The same is true for a squat 1RM calculator and a deadlift 1RM calculator: enter one completed set and keep your movement standard consistent. For a weighted pull-up, enter total system load, body weight plus added weight, so the estimate covers the full movement.
Bench 1RM calculator
Use a repeatable touch point and pause standard. The estimate helps you choose a heavy single or percentage-based back-off work.
Squat 1RM calculator
Keep depth, stance, and bracing consistent so the number compares cleanly across sessions.
Deadlift 1RM calculator
Start each set from the same position and use the same lockout standard.
1RM calculator weighted pull-up
Add body weight to external load before entering the number. Subtract body weight from the result if you want added weight alone.
1RM calculator formula and RPE
This tool uses the Epley formula: 1RM = weight × (1 + reps / 30). It is transparent and useful for everyday training. A 1RM calculator RPE input can refine a result when a set stops with reps in reserve, but this page keeps the form to weight and repetitions so it stays quick. Treat an easier-than-RPE-10 set as a conservative starting point.
EPLEY FORMULA
1RM
weight × (1 + reps / 30)
10RM first, then 1RM
For higher-rep inputs, the calculator estimates a 10RM first, then projects a 1RM. This keeps the formula closer to the range where it is most useful.
Plan between heavy tests
A 1RM calculator powerlifting workflow can guide bench, squat, and deadlift percentages. Use competition-style technique and safety equipment.
1RM calculator FAQ
What is a 1RM calculator?
A 1RM calculator estimates the heaviest weight you could lift for one clean repetition from a lighter set you have already completed. It saves you from testing a true maximum every time you want a training number.
What is my 1RM?
Enter the weight and repetitions from one hard set. This page uses the Epley formula to estimate your one rep max. Your actual maximum can vary with technique, sleep, fatigue, and the exercise.
What is the 1RM calculator formula?
The Epley formula is weight multiplied by one plus repetitions divided by 30. It is a common starting point for a one rep max calculator because it is quick and easy to understand.
What does RPE have to do with a 1RM calculator?
RPE describes how many clean repetitions you had left. This intentionally simple calculator does not require an RPE field, so use a hard set close to failure for the clearest estimate.
How do I calculate a weighted pull-up 1RM?
Add your body weight and the added weight, then enter that total load with the repetitions you completed. The result is a total-load estimate. Subtract body weight if you want the estimated added-weight number.
Can powerlifters use this 1RM calculator?
Yes. Use it for bench press, squat, and deadlift planning between heavy tests. For powerlifting, keep competition-standard technique and use a spotter or safety equipment for heavy work.
Keep the estimate with your training.
Log your sets in Ironi and your progress stays in one place.