How accurate is a squat max estimated from five reps?

Reasonably accurate, and usually a little conservative. The squat is a long-range lift where high-rep sets are limited by breathing as much as by strength.

Should I test a real squat max?

Only with a rack with safety pins set at the right height. A failed squat is recoverable if the pins are set and dangerous if they are not.

Front squat or back squat?

They need separate numbers. A front squat is typically around eighty percent of a back squat, and using one estimate for both will get the weights wrong.

Calculator · preset of one rep max calculator

Squat one rep max calculator

Estimate your squat max from a set of a few reps. Four formulas, the spread between them, and the weights to train at.

Open the full one rep max calculator to change anything this preset fixes

Estimate your squat max

Weight lifted

Clean reps

Estimated one rep max

114.8 kg

The four formulas span 112.5 to 117.5 kg. Train off the average.

Epley: 116.7
Brzycki: 112.5
Lombardi: 117.5
O'Conner: 112.5

Training weights

Reps	Percent	Weight
1	100%	114.8
2	95%	109
3	93%	106.7
4	90%	103.3
5	87%	99.9
6	85%	97.6
8	80%	91.8
10	75%	86.1
12	70%	80.3
15	65%	74.6

Percentages are the ranges programs are written against. They are a starting point for picking a weight, not a promise about how many reps you will get on the day.

What the four formulas are

Epley: The most widely used. Runs high above about ten reps.
Brzycki: Close to Epley at low reps, more conservative as reps climb.
Lombardi: A power curve. The most conservative of the four at high reps.
O'Conner: Epley flattened. Sits lowest across most of the rep range.

How it works

The squat is where estimated maxes work best. It is a long-range lift with a big muscle mass behind it, and sets of three to eight track closely enough with a single that the formulas land near the truth.

Enter a hard set and the calculator returns four estimates and their average, along with the percentages most squat programs are written against. A hundred kilos for five comes out near one hundred and fifteen.

Squat estimates from very high rep sets run low rather than high. A set of fifteen ends because you cannot breathe, not because the legs are done, so anything past about ten reps underestimates what a single would be.

If you do test a real max, set the safety pins first and set them at a height that lets you sit into them. That single precaution is what makes squatting heavy alone reasonable.

Questions

How accurate is a squat max estimated from five reps?: Reasonably accurate, and usually a little conservative. The squat is a long-range lift where high-rep sets are limited by breathing as much as by strength.
Should I test a real squat max?: Only with a rack with safety pins set at the right height. A failed squat is recoverable if the pins are set and dangerous if they are not.
Front squat or back squat?: They need separate numbers. A front squat is typically around eighty percent of a back squat, and using one estimate for both will get the weights wrong.