Read the measurement label
Ubbi's official bag page declares flat dimensions18.5inches wide by33.5inches high. Those measurements describe a flattened bag,not a round opening diameter or the pail's footprint. The same page separately lists13gallons/49.2liters. Keep each field's meaning visible rather than combining them into a geometric model of the installed bag. The selected Easy Roll18package image separately labels83.8x29.8cm(32.99x11.73in)for its bags;these are not the retail refill-carton dimensions or a compatibility proof.
Do not invent a usable-volume formula
A flexible bag changes shape when fitted into a holder and pail. Its nominal capacity does not establish the volume available inside a particular container. The website has not measured installed volume,closure allowance or loading behavior. We therefore provide no calculation that multiplies flat width and height to predict usable capacity or a number of diapers.
Separate retail overall fields
The selected Target Ubbi page lists overall dimensions that differ from the manufacturer's flat-bag declaration. Estimated shipping dimensions describe another object again:the shipping package. We retain the discrepancy and use the clearly labeled manufacturer flat dimensions where relevant. We do not decide that one set is a new installed size or quietly average the numbers.
Cassette dimensions do not reveal film
A round cartridge's outside width and height may help identify a package,but they do not provide usable film length. Film thickness,folding,internal volume and unused portions are not established here. The cost tool only accepts an actual verified length entered by a user. It never estimates length from a cassette diameter,weight or photograph.
A drawer-storage example
Someone checking whether a sealed pack fits a shelf needs the actual packaged dimensions,not the opened bag's33.5-inch height. Conversely,a bag-fit question needs the relevant bag specification and pail instructions rather than the shipping carton size. Write which object is being measured before comparing numbers. The same unit does not mean the measurements describe the same thing.
Use exact conversions carefully
One inch equals2.54centimeters,but converting units preserves only the stated measurement,not its scope. A flat width in centimeters remains a flat width. A volume in liters remains a nominal bag-volume statement. Unit conversion cannot establish compatibility,material thickness or usable capacity that the original source did not provide.
Ask for the missing specification
If a dimension is essential and its scope is unclear,ask the manufacturer for the exact selected version. Keep the unknown field blank rather than using a nearby shipping measurement. This makes a purchase decision easier to review and avoids turning a specification table into an unsupported engineering claim. Physical installation and independent content review remain pending.
Match the object before comparing dimensions
When contacting support about a dimension discrepancy,name whether the field concerns the flat bag,installed bag,refill housing,retail carton or shipping parcel. A question asking only which width is correct can receive an answer about the wrong object. Include the exact selected product and source label. This makes the missing specification actionable and avoids a false conclusion that two measurements conflict when they may describe different things. The site does not measure these objects or infer a fit from their photographs.
Sources & scope
Checked November 4, 2026. Manufacturer and retailer references support the specific statements. Dated displayed prices are not final checkout quotes, performance rankings or performance testing. This shopping reference does not replace the exact product label or qualified individual advice. Exact current package/model review and independent safety/content review remain pending.
Ubbi US: plastic bags and selected variants ↗
Target: Ubbi75 / TCIN50519213 ↗
Keep reading
Easy Roll18: one refill,18bags,not18cartridges ↗