How do I estimate my one rep max without maxing out?

Do one hard set of 3 to 5 reps, then use the Epley formula: weight x (1 + reps / 30). The result is a good estimate of your one rep max and is usually accurate within a few percent, without the risk of actually going for a max.

A worked example

Say you bench 185 lb for 5 clean reps, with maybe one left in the tank.

• 185 x (1 + 5 / 30)
• 185 x 1.167
• About 216 lb

So your estimated one rep max is about 215 lb. If you did 225 lb (100 kg) for 3 reps, you'd get 225 x 1.1, which is about 248 lb.

Rules to keep it accurate

• Stay at 5 reps or fewer. The formula gets less reliable past about 10.
• Stop the set when your form would break, not when the bar stops moving.
• Use the same lift and the same technique each time. Paused reps and touch and go reps give different numbers.
• Do it fresh, not at the end of a long session.

A quick reference table in your head

Roughly, these are the percentages of your max you can lift for a given number of reps:

• 1 rep: 100 percent
• 3 reps: about 93 percent
• 5 reps: about 87 percent
• 8 reps: about 80 percent
• 10 reps: about 75 percent

People differ a lot though, so treat these as averages.

Why not just test it

You can test a true max, and some people enjoy it. But it needs a spotter or safety bars, a good warm-up and a day when you feel good. A heavy single is also a lot harder to repeat consistently than a five rep set. For tracking progress, an estimate from a hard five works better, and it lets you train normally.

If you get the weight wrong and the set ends up feeling easy, add weight and try again another day. Estimates only mean something when the set is truly hard.

If you want a number to chase that needs no barbell, League of Fitness has a Max mode: a solo 60-second personal best attempt at squats, push-ups or sit-ups, with the phone camera counting the reps. It is a rep test and not a one rep max, but it is easy to repeat and beat.