One-Rep Max (1RM) Calculator
Estimate your max lift from any set, with a training-weights table · free, no signup
See One-Rep Max (1RM) Calculator in action
Free One-Rep Max Calculator
Your one-rep max (1RM) is the heaviest weight you could lift once with good form. Testing it directly is risky, so most lifters estimate it from a harder set of several reps. Enter the weight and the reps you completed and this calculator applies six standard formulas (Epley, Brzycki, Lombardi, O'Conner, Mayhew and Wathan), shows each one and averages them for a more stable estimate.
It also builds a percentage table so you can pick the right weight for your goal: heavy sets near 85 to 95 percent for strength, 70 to 80 percent for muscle growth and 50 to 65 percent for endurance. Works in kilograms or pounds for bench press, squat, deadlift, overhead press or any barbell lift.
Key features
Six formulas, one average
Epley, Brzycki, Lombardi, O'Conner, Mayhew and Wathan side by side.
Percentage table
Training weights from 100% down to 50% of your max with typical reps.
kg or lb
Switch units instantly.
Instant and private
Runs in your browser.
How to use it
- Pick kg or lb.
- Enter the weight you lifted.
- Enter how many clean reps you completed.
- Read your estimated max and the table of training weights.
Worked example
Example
80 kg for 8 reps: Epley gives about 101 kg and Brzycki about 99 kg, so your estimated 1RM is roughly 100 kg. 80% of that is 80 kg, which you should be able to lift for around 8 reps.
Who uses this tool
Lifters planning programs
Set working weights as a percentage of your max.
Beginners
Know a safe starting weight without a max attempt.
Powerlifters
Pick attempts for meet day estimates.
Tips for the best results
- Use a set of 10 reps or fewer. The fewer the reps, the more accurate the estimate.
- Use a set taken close to failure with strict form.
- Retest every 4 to 8 weeks as you get stronger.
Common mistakes to avoid
- Using a set of 20 or more reps. Formulas become unreliable.
- Counting sloppy reps. Only clean reps count.
- Treating the estimate as a guarantee. Always use a spotter for heavy lifts.
Why use AZRS QuickFix?
It is 100% free, needs no signup and has no watermark or usage limits. The tool runs in your browser, so what you type stays on your device, and it works on phones, tablets and desktops. New tools are added every week — bookmark this page or browse the full QuickFix toolbox.
Frequently asked questions
What is a 1RM?
The most weight you can lift for a single repetition with proper form.
Which formula is best?
No single formula wins for everyone, which is why the average of all six is shown.
Is it safe to test a true 1RM?
It carries injury risk. Estimating from a submaximal set is safer, and a true attempt should always use a spotter or safety bars.
Does it work for any exercise?
It is designed for barbell and dumbbell lifts, and is less meaningful for bodyweight or machine exercises.