How big is 7cm keychain?

7 cm (2.75 inches) is a medium-sized keychain. Here's a visual comparison to help you understand its dimensions:

It's about the length of a standard lipstick

It's similar to the width of a credit card

It's slightly longer than a standard USB flash drive

It's compact enough to fit comfortably in your hand, pocket, or bag, while still being large enough to display a design, logo, or ornament.