In theory, the gym is supposed to supply the weights for you to lift while you’re there. But sometimes their collection doesn’t have exactly what you want. If their smallest weight plates are 5kg or 10kg, be a rebel: bring smaller ones in your gym bag.
After all, if you only have 2kg plates, you have to adjust the total weight on the barbell by 5kg at a time. If you’re struggling with something like an overhead press, especially as a new lifter, 5kg is a huge jump.
My gym has 2.2kg plates, and for that I am grateful. But not all gyms do, and sometimes even when a gym has small plates there may only be a single pair up for grabs. Being small, they may also go missing, only to turn up weeks later underneath some larger piece of equipment.
So if you want to be sure you’ll have those 2.5 or even .5kg plates available when you need them, bring your own! If you’d like to buy a pair, search for “fractional” or “micro” plates.
Before you start looking for smaller and smaller plates, note that precision is elusive. Even the large plates at the gym are not always the exact weight marked, so this 20kg plate might already be a few ounces lighter or heavier than that 20kg plate. I wouldn’t bother with teeny tiny plates, even though you can buy them in increments as small as a quarter pound.