The fit guide
Will your tumbler fit?
Measure the base, not the top. If a Post-it note is wider than your tumbler's base, you're good — and the 40oz Stanley is.
See the Post-it test →The 40oz Stanley fits.
It's the base that matters, and the big Quencher's sits right in Steadi's range. Owala, Yeti, and most popular tumblers fit too.
Ten-second check
The Post-it test.
A sticky note is the gauge. No ruler, no math — just stand your tumbler on one.
- 1Grab a Post-it.
Any standard square sticky note works.
- 2Stand your tumbler on it.
Empty is easiest to handle — fit is about the base, not what's in the cup.
- 3Look at the edges.
If the note is as wide as the base or wider, all the way around, you're good. If the base spills well past the note, it's too wide.
The 40oz Stanley
The cup most people here already own. It settles into Steadi and stays up — handle out top, base held below.
Owala and Yeti fit the same way.
The gallery
What fits — and what's too small.
The base is the whole story. If it's about Post-it width, it's in.
The one limit
Where it stops.
The fins need a base to hold onto. A very narrow bottom — an espresso cup, a small juice glass — is too small to grip, so it sits loose. If your tumbler's base is close to a Post-it's width, you're well inside.
Your 40oz fits. Go build your set.
Pick your packs and give each tumbler its own color.
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