The Correct Use of Fractional Plates

by Mark Rippetoe | February 15, 2022

People keep posting questions on the forums about their bench and press that lead me to strongly suspect they are trying to take 5lb/2.5kg jumps long after they shouldn't be. As noted in my article The First Three Questions, progress on the upper body lifts – and for most women, all the lifts – will eventually taper down to smaller jumps, making plates that weigh less than 2.5lb/1.25kg absolutely necessary for continued progress.

Plates are available from several manufacturers in denominations that allow you to take a half-pound jump on the bar, if necessary. Jumps of 0.5, 1, 1.5, 2, 2.5, 3, 4, or 5lb ought be an option for your training, to allow you to precisely match you adaptive capacity to the loads. Or you can make them yourself out of washers or pieces of flat chain from the hardware store.

But the plates themselves are not the magical cure for getting unstuck. If you completed the previous work sets called for by your programming, there is an incremental increase you should be able to make that allows the next workout to be completed. The problem is controlling that increase, because the fractional plates are not the only weights you're lifting.

If you go to a commercial gym and have to use the bar and plates that are available right now, and that bar and plates are not the same bar and plates you used last time, you are not in precise control of the load on the bar. If you've been training 5 months, you benched “185”x5x3 last time, and the 5th rep of the last set was slow, “190” will be too heavy for all 15 reps. You'll need to load “187.”

Note the scare quotes. Unless you weighed the bar and plates on a scale, you do not know what you actually lifted, because all cast-iron plates and most bars are only accurate within a certain tolerance. The more expensive the equipment, the closer the tolerance to the face value of the equipment. But it is almost a 100% certainty that the weight you think you loaded on the bar is not what the thing actually weighs. I have seen “45lb” plates that weighed 42.5 and 54.75lb. Same logo, same model, same paint. No shit. It's cheaper to sell you extra iron that it is to mill it off.

Sometimes this doesn't really matter. If you are training at home and you use the same bar and plates every time, “185” may well weigh 184 or 186, but if you precisely control the increases, and you have weighed all the plates in the set and marked them for actual weight, you have precise control over your jumps with your fractional plates.

But in a commercial gym with 50 different “45lb” plates, 30 different “25lb” plates, etc., your fractional plates are irrelevant – if you don't know what weight you're adding 2lbs to, you don't know what you're lifting. The incremental increase from last workout is really what matters, not the absolute weight, because the increase is the progress.

In my gym we have several pairs of plates marked, and all the bars are numbered, so that you can precisely control your increases – if not your absolute loading – by using the same bar and plates every time you train. Our fractional plates then allow a precise 2-pound jump for this workout. And that's the point. It may be that you need to mark a bar and a set of plates in your commercial gym (be sneaky, management may not understand) and take your own fractional plates with you.

There comes a time when everybody needs precise control over a smaller-than-5lb jump – especially women and men at lighter bodyweights – if actual training is the objective. You have to understand the process, and you have to be equipped to follow it.