How to measure a water bottle for Steadi
Measure the actual bottom: bottle capacity, mouth size and a brand name cannot establish fit.
Start at the bottom
Use a ruler or caliper across the widest part of the container base that must sit between the fins. The confirmed Steadi range is 2–3.15 inches inclusive, or 50.8–80.01mm. Do not use the mouth opening, shoulder width or an approximate visual guide as the boundary.
Capacity is not a diameter
A 16oz bottle can have a different shape from another 16oz bottle. Likewise, standard-mouth and wide-mouth versions can differ even under one brand. Choose an exact model and generation, then measure the actual base. Do not assume all 32oz or 40oz bottles fit.
Published dimensions are a starting point
Hydro Flask lists 2.85 inches as the product diameter for its 24oz Standard Mouth with Flex Straw Cap. Nalgene Canada lists 2.75 inches for its 16oz Wide Mouth bottle. These manufacturer dimensions are useful screening references, not our physical Steadi fit tests. Check your own bottom, accessories and full seating before use.
Account for boots and sleeves
An added boot can increase the outside width or prevent the bottle sitting fully down. Measure the configuration you intend to use. Remove an optional boot only if appropriate for your bottle, then recheck. Do not force the fins around a pairing that will not seat naturally.
Check the base shape as well as the number
A stepped, deeply curved or irregular bottom needs its own seating check. Diameter inside the range is only one condition. Keep the drink upright, seat it fully and inspect the holder’s contact with the surface. If uncertain, send the exact model and a photo to Steadi support.
Do not confuse the two measurements
The container fit range is 2–3.15 inches. The holder’s footprint is 5.2 inches. A bottle may fit the fins while the chosen ledge is too narrow for the holder. Use both tools on the fit page: diameter first, then available resting space.