Estimated 1RM versus actual 1RM

I’ve noticed that when I compute my estimated 1 rep max, if I happen to have an actual 1RM that I’ve tested recently for that lift, my estimated 1RM is always lower. Often the difference is only 5-10 pounds, which I figure is probably just within the error of the estimate, but occasionally it will be a bigger difference, perhaps 20 pounds or so. If this happens consistently for a particular lift, should I take this as a sign that I’m underestimating my RPE for that lift?

It could be, or alternatively you could just be better at performing singles and the percentages are not accurate for you in particular. Some have advocated for developing your own personal customized RPE chart for this reason, although it’s probably overkill for most people.

Thanks! I think I probably won’t worry about it - collecting the data to construct a personalized chart seems like it would be quite time consuming,and I’m probably better off just training.

Just an interesting follow-up note on this: When I posted my original question, I was in the last few weeks of preparing for a deadlift competition in early June, and the deadlift was the lift where I was observing the biggest discrepancy between my e1RM and my previously tested 1RM. Since tapering for the meet (and pulling a 10 lb PR and feeling like maybe I could have pulled 10 lbs more than that), I’m finding that now that I’m back in the swing of ordinary training, my deadlift e1RMs are a lot closer to my max, although still a bit under. So possibly I was just fatigued from doing a lot of deadlifting.