The fit guide
Measure the bottom, not the top.
Every cup is wider at the rim than at the base — and the base is the only part that matters here. If the bottom of your drink measures about 2 to 3 inches across, it settles in and holds steady.
Check yours with a sticky note ↓Measured across the base of the container, not the rim — both ends inclusive. The exact figures land when we caliper each container. Until then the sticky note is the reference, and one is exactly 3 inches.
The ten-second check
The sticky-note test.
A standard sticky note is exactly 3 inches across, which makes it the ceiling reference — no ruler, no guessing, and you already own one.
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Grab a sticky note.
The standard square one, 3 × 3. Any color works.
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Set your cup on it, empty.
Centered, so you can see all four edges of the note.
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Look at the edges.
Base inside the note: it fits. Base hanging over: too wide.
Under 53 mm is the other way to miss — see the floor, below.
Real sticky note under a Stanley 40 oz
Shot square from above
The gallery
Your cup is probably in here.
Everyday containers on the same gauge, shot the same way. Two of them don't fit — a fit guide where everything fits is a sales page.
on the sticky note
The most-asked cup
Yes, the 40 oz Stanley fits.
It's the tumbler most likely to already be on your coffee table, and it's the first thing people check. Drop it in and it settles in — no balancing act, no wedging it between the cushions.
Stanley Quencher 40 oz · [MEASURE] in base
on the sticky note
on the sticky note
on the sticky note
on the sticky note
on the sticky note
on the sticky note
base over the note edges
on the sticky note
on the sticky note
on the sticky note
lost inside the note
The part most guides skip
There's a floor, too.
Fit ranges usually come with just a ceiling, because a floor is an admission that some cups don't fit. This one has both. Below 53 mm, the base is too narrow for the fins to reach — nothing breaks, the cup just sits loose and rattles around instead of settling in.
A loose cup isn't holding steady, so we'd rather rule it out here than have you find out on your couch.
Ruled out by the floor
- Espresso cups too narrow
- Most shot glasses too narrow
- Some narrow travel mugs measure the base
At 53 mm or more, and inside a sticky note? You're set.
Edge cases
The cups people actually ask about.
Can I leave the koozie on?
Take it off. The holder grips the can directly and holds it steady — which a koozie doesn't do. A koozie inside the fins is usually too wide.
What about mugs and cups with a handle?
Fine. The fins hold the base; the handle sits outside them. Measure the base like any other cup.
My cup is tapered — wider at the top than the bottom.
That's most tumblers, and it's exactly why you measure the bottom. The fins grip the base, so the base is the number that matters. The rim can be as wide as it likes.
What if the base sits right at the sticky note's edge?
In. The range is inclusive at both ends, so a base that matches the note edge for edge fits. Overhanging the note is what's too wide.
Does it matter if the drink is full?
No. Fit is about the width of the base, and that doesn't change with what's in the cup. Full is the normal case — it's built to hold a full drink, and the test works the same either way. Just run the sticky-note check with the cup empty so it's easy to handle.
My cup isn't in the gallery.
The sticky note settles it in ten seconds. Still not sure? Email [email protected] and we'll give you a straight answer.
If it fits, the rest is easy.
Free shipping on every order. Ships from Orange, California in 1 business day. Thirty days to change your mind.
Get yours — from $24.95Checkout is on steadilabs.com — Steadi Labs is the company that makes it.