For something to be bite-size it should be able to be consumed in one bite or one mouthful. The adjective can also describe things which are attainable or easily handled. It should always be used with a hyphen. Though in the tradition of hyphens, it will most likely be phased out at some point in this word’s lifetime.
Bite-sized is a variant spelling, though in the present tense is the official entry in most United States dictionaries. Bite-sized is the main entry in some European dictionaries. In actual usage, they seem to be evenly matched.
Examples
These pretty pieces also make great gifts, especially when filled with bite-size treats and wrapped with a shimmery ribbon. [The Journal Gazette]
The Economist is to launch its first-ever daily edition, a bite-size digital briefing designed to complement the 171-year-old weekly news magazine. [The Guardian]
If developers use these tools, they can quickly display bite-sized notifications designed specifically for the Apple Watch’s smaller screen. [Business Insider Australia]
His and Claudia Boulton’s terrific, comedic Eris provide clever devices to break the narrative into bite-sized chunks. [Liverpool Confidential]
If you have that sense of security and stability that comes with all the I Love Yous and sharing a blissful life with someone, you gradually feel less and less like you have to hide the fact that you like to actually prefer Miracle Whip to real mayonnaise and slather pieces of raisin bread with it at 3am when you’re feeling peckish, or that you rub deodorant on your chest secretly during the swift motion from one armpit to the next, or that it takes you until about Christmas every year, when the festively wrapped milk chocolates swoop in as a suitable replacement, to get over the bite-sized Halloween candy bars, so you stockpile boxes of them in your closet and no one else knows. Â [The Coast Halifax]