Best 5- to 6-inch twin mattresses

Top pick: Novilla 6-Inch Twin Gel Memory Foam — the strongest all-rounder here: a true twin at 6 inches, gel memory foam that sleeps cooler than plain foam, and the best rating of the bunch (4.7 from ~500 reviews). Good for a guest room, kids' room or a low-profile bed frame.

Who the others suit:

• MLILY 6-Inch Twin — medium-firm memory foam if you want a slightly more supportive feel.
• FDW 6-Inch Twin Gel — the budget workhorse, with thousands of ratings behind it.
• Zinus 6-Inch Twin Green Tea — a long-standing pick if you like the green-tea foam line.
• Mainstays 6-Inch Twin Innerspring — choose this if you prefer a bouncier, traditional spring feel.
• prettsun 5-Inch Twin — the thinnest option, best for trundles and bunk beds with tight clearance.
• Milliard 5-Inch Trundle — purpose-built for a trundle frame.

One note: the Lucid 6-Inch and EGOHOME 6-Inch Kids listings I found are full/queen sizes, so I left them out.