one rep max calculator,does it accurate?

[trapz101]

as per title....are they reliable?

[jpm101]

If you mean the percentage of a weight, using a one rep max as a guide, for starting weight in a exercise...no, not a good   indicator at all. Though it is the standard approach...don't know why, but it is.

Everyone is different and can respond in different ways. Have to experiment, and find the suitable weight adjustment for yourself. Doesn't take much time or effort at all. But do it after a good warmup of the exercise.  Doing it stone cold can be a big mistake.

Good Luck.

[Yev33]

I have used this one in the past and it's pretty accurate.
(Weight x number of reps x 0.033)+weight=1rm

It's not exact obviously but I have found that it is accurate within 5%. It works best if you are using a multiple rep max under 10 reps, the higher the reps the less accurate it becomes (for obvious reasons).

I think it is most useful when you are going for an actual 1rm and using it as a guide to get you in the ball park of weights to attempt. For example, if you know you can only do 315x6 you aren't getting 405 for a single so why risk injury. But lets say you are getting 365x5 and you are intimidated by 405 you can probably pull it off without even realizing it.

I think it is a great tool when used properly.

[chaos]

as per title....are they reliable?

No. Only way to find out is to do it.