3 Rep Max Calculator

Working Weights Around Your 3RM

A top set and the back-offs that follow it, all sets of 3.

Top set first, then back-offs. Two or three sets of three at 90 to 95 percent of your 3RM is a solid heavy day without turning it into a test.

How the 3 Rep Max Calculator Works

Any set in, a heavy triple out.

Your 3RM is the heaviest weight you could lift for three clean reps and no fourth. To find it, the calculator first converts the set you entered into a one-rep max using five established prediction formulas, then runs those same five equations backwards to work out the weight for three reps and averages the answers. A triple usually lands around 92 percent of a one-rep max, which is why the number comes out close to, but meaningfully below, your single.

Entering 225 lb for 5 reps points to a one-rep max near 260 lb and a 3RM near 239 lb. The three other rep maxes shown beside the headline come from the same calculation, so you can see the whole shape of your strength rather than one slice of it.

Why the 3RM Is the Strength Lifter's Number

Near maximal load, with a margin you can survive.

A triple is heavy enough to train the thing a single tests. The bar moves slowly, your brace has to hold for three attempts rather than one, and technique has nowhere to hide. What a triple gives you that a single does not is a margin for error. Miss the third rep and you have missed a rep. Miss a max single and you have a bar on your chest or a back that is about to remind you for a week.

That is why heavy triples sit at the sharp end of so many strength programs. Week two of a 5/3/1 cycle finishes on threes. Peaking blocks step down from fives to triples to singles as a meet approaches. Powerlifters pick openers from what their triples have been doing, because a weight you can hit three times is a weight you will not miss once under lights.

The 3RM is also a good honesty check. If your calculated single keeps climbing but your triple has not moved in two months, the single is optimistic. Strength that is real shows up across rep ranges, not in one number.

Testing a Triple Properly

If you want a real 3RM instead of an estimated one.

Warm up fully, then work up in singles or doubles until the weight feels heavy but fast, and take one attempt at three. One. A second attempt at a similar weight almost always goes worse, and a third turns a test into a training session you did not plan. Use the estimate above as the target and rack it if the second rep grinds.

Two things spoil a triple more than anything else. The first is letting the brace go between reps, which turns rep three into a different exercise. The second is resetting badly on the deadlift, where a sloppy second setup costs more than the weight does. Take the time, then pull.

What the Estimate Cannot See

Where a converted triple drifts.

The estimate is only as honest as the set you fed it. If you stopped two reps short of failure, your real 3RM is higher than the number above. If your form fell apart on the last rep, it is lower. Entering a set of ten to estimate a triple works, but the further apart the two rep counts are, the more the answer relies on the formulas rather than on you.

Lift choice matters too. Triples on the deadlift are harder than the maths suggests, because every rep starts from a dead stop and grip and lower back fatigue stack up fast. Squat and bench triples usually track the estimate more closely.

More Rep Max Tools

The rest of the family, all from the same set.

Frequently Asked Questions

What lifters ask about heavy triples.