One Rep Max Calculator

Estimate your one rep max safely

Your one rep max (1RM) is the heaviest weight you can lift once with good form. Testing it directly is tiring and risky, so this one rep max calculator estimates it from a lighter set you can do for several reps. It also gives a training table from 100% down to 50% of your 1RM.

How to use it

1. Choose kg or lbs. This sets the unit label; it does not convert numbers.
2. Enter the weight lifted and the reps performed (1 to 30).
3. Pick a formula: Epley, Brzycki, Lander, Lombardi or Average (the default).
4. Read your estimated 1RM and the training percentage table in 5% steps.

The 1RM formulas

Formula	Calculation (w = weight, r = reps)	100 kg × 5 reps
Epley	w × (1 + r ÷ 30)	116.7 kg
Brzycki	w ÷ (1.0278 − 0.0278 × r)	112.5 kg
Lander	w ÷ (1.013 − 0.0267123 × r)	113.7 kg
Lombardi	w × r^0.10	117.5 kg
Average	Mean of the four above	115.1 kg

With Epley and Brzycki, a single rep returns the weight itself.

Using the training table

Many programs set working weights as a percentage of your 1RM. With an estimated 1RM of 115.1 kg:

• 90% = 103.6 kg — heavy sets of very low reps.
• 80% = 92.1 kg — common for strength work.
• 70% = 80.6 kg — moderate sets of higher reps.

Tips for a better estimate

• Use a set taken close to failure with good form.
• Sets of about 3 to 10 reps give more reliable estimates. The calculator accepts up to 30 reps, but results at high reps can be far off.
• Formulas can disagree by several kilos, so use the Average or stick to one formula to track progress.
• Use a spotter or safety bars when you work near your max.

Frequently asked questions

Which 1RM formula is most accurate?

None is exact for everyone. They agree most closely at low reps. The Average option smooths out the differences.

Does it work for bench press, squat and deadlift?

Yes. The formulas work the same for any lift; enter the weight and reps for that exercise.