Nothing is more distracting than gear that doesn’t fit properly, and hitting anything with a badly fitting glove can result in unnecessary injury or just be annoying. If you haven’t purchased any type of glove before, your top considerations will be fit, purpose, weight, weight distribution, and desired protection level. The rule of thumb is to keep two pairs on hand, one for training and one for sparring, but if you want to start with just one, you have to choose carefully.
For a mix of boxing and kickboxing as a fitness hobby, you’ll be safe going with a Thai boxing glove, as you can do different types of bag and pad work as well as clinching with them. They aren’t padded on the palm side so they are flexible. For straight boxing, you should go with a classic boxing glove – most gyms have requirements regarding weight class and glove weights for sparring. In both cases, measure around your hand both with and without wraps. Handwraps will affect how snugly a glove fits.
The heavier a glove, the larger it will be in the hand compartment. Some people like to train with heavier gloves for the extra weight and spar or compete with lighter ones for speed, but if you have small hands, you’ll likely top out at a 14-ounce glove just on fit. Further regarding glove weight, the heavier ones do, of course, provide greater protection for sparring partners (which is why many boxing gyms have requirements dictated by a fighter’s weight) and your hands, so go for a minimum of 14 ounces if you’re fighting casually or noncompetitively.
Wrist measurement is also important, as many gloves have velcro closures that might not be snug enough or come undone if you’re really whacking the heavy bag. A glove with stiff wrist support isn’t any good if the closure is too loose, so be sure to get a snug fit there as well.
Different glove brands layer and distribute the padding differently. For example, looking at Fairtex and Twins 16-ounce Thai boxing gloves side by side, you can see that the two appear very different, with the Fairtex appearing to be much smaller. It has a very square shape across the knuckles. Twins are bulkier in both the top and sides and the padding extends toward the wrist.