What’s the Difference Between a Highball Glass and a Rocks Glass?

highball glass and rocks glass side by side

Choosing the right glass can quietly transform a cocktail’s character. Two of the most essential shapes behind the bar are the highball glass and the rocks glass. Knowing when to use each isn’t just tradition—it’s also about taste, temperature, and drinking experience. Here’s what distinguishes these two iconic vessels.

Shape and Size: Taller vs. Shorter

A highball glass is tall, straight-sided, and typically holds between 250–350 ml. Its slender design preserves carbonation and allows for plenty of mixer.
A rocks glass (also called an old-fashioned glass) is shorter and wider, with a capacity generally between 180–300 ml. The broad shape makes swirling or muddling easy.

Function: The Right Glass for the Drink

Highball glasses suit mixed drinks that require a generous pour of non-alcoholic mixer—think gin and tonics, rum and cola, or a classic screwdriver. The tall, slim shape keeps the drink cold and the bubbles lively.
Rocks glasses are designed for drinks served over ice, especially those with less mixer or none at all. Old Fashioneds and Negronis shine when poured over a large ice cube, allowing the spirit’s aroma to open up as it chills.

old fashioned cocktail in a rocks glass with orange twist

Other Details: Texture, Dilution, and Experience

Highball glasses maximize the refreshing, crisp sensation of fizz and ice. The tall design means the ice melts slowly, preventing the drink from watering out too quickly.
A rocks glass invites sipping and slow appreciation. The wider mouth exposes more surface area of the spirit, making aroma and flavor easier to enjoy—perfect for bold, aromatic drinks.

Which to Use? Quick Reference

Choose a highball glass for long drinks with a high mixer-to-spirit ratio.
Pick a rocks glass for spirit-forward cocktails or neat pours over ice.