How to Estimate Your 1RM Without Maxing Out

Why estimate instead of testing?

True maxes are fatiguing, technically demanding and need a peak to do well. Testing them often takes away training time and adds risk. An estimate from a submaximal set is enough to set training weights, track progress and plan a meet, and you can get one every session.

Rep-max formulas

The two most common formulas estimate a max from the weight and reps of a hard set:

• Epley: 1RM = weight × (1 + reps ÷ 30)
• Brzycki: 1RM = weight × 36 ÷ (37 − reps)

For 140 kg × 5, Epley gives about 163 kg and Brzycki about 158 kg. They agree closely around 10 reps; Epley gives higher numbers below that.

Adding RPE makes it more accurate

The formulas assume the set went to failure. Most of your training sets don't. If you rate your sets with RPE, add the reps you had left before using the formula: 5 reps at RPE 8 counts as 7 reps to failure.

That means you can estimate your max from normal working sets without ever training to failure. The 1RM calculator does this for you.

How accurate is it?

• Most accurate from sets of about 2–6 reps close to failure. Estimates from more than about 10 reps get much less reliable.
• It depends on you. Some lifters can do many reps at a given percentage; others can't. If your estimates keep coming in high or low, adjust for it.
• It depends on the lift. Deadlift reps fatigue differently from bench reps, so the same formula fits some lifts better.
• Honest RPE matters. An RPE 8 that was really a 9.5 inflates the estimate.

Treat the estimate as a range, give or take a few per cent, not an exact number.

Other ways to estimate

• Heavy singles at RPE 8–9. A single at RPE 8 is roughly 91% of your max; at RPE 9, about 94%.
• AMRAP sets: a set of as many reps as possible at a fixed weight, plugged into the formula. Stop at technical failure, not complete failure.
• Bar speed: velocity trackers can estimate a max from how fast submaximal reps move, if you collect enough data.

When to test a true max

Save true maxes for the platform, or for the end of a peaking block when you need the real number. Even then, a heavy single at RPE 9 tells you most of what you need to know, with less fatigue.

Estimated maxes in Iron Raven

Iron Raven estimates your max from every logged set, using weight, reps and RPE, and tracks it over time on your Progress charts. The in-app 1RM calculator and the web version use the same estimate.