Oct. 27, 2026
Packaging & Printing
A 303 tinplate beer can top end is a metal closure intended to be seamed onto a compatible can body; the “303” designation should be treated as a size or format identifier, not as a complete specification. In some can-size conventions, 303 may indicate a nominal diameter of 3 3/16 inches, equivalent to approximately 80.96 mm, but designation practices can vary. Before ordering, confirm the end’s actual dimensions, profile, coating, opening feature, and compatibility with your can body and seaming equipment. At Wanhua, we recommend sourcing from a dimensioned drawing and confirmed application details rather than relying on the size code alone.
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This guide is for beverage manufacturers, can makers, packaging procurement teams, and distributors evaluating 303 tinplate beer can top ends. It is useful when you are comparing specifications, checking whether an end fits an existing line, or preparing a request for quotation. It can also help buyers identify the technical information a supplier needs before confirming availability and pricing.
A can top end closes the open end of a filled can through a double-seaming operation. The seamed joint must work with the can body’s flange and the end’s curl and countersink geometry to create a secure closure. Depending on the design, the end may also include an opening feature such as a scored panel and tab.
“Tinplate” generally describes steel sheet coated with tin, but the phrase alone does not define the full material specification. Buyers should confirm the metal grade, thickness, coating details, internal and external coatings, and any applicable food-contact requirements for the intended market. We advise matching those details to the beverage, filling process, and storage conditions.
Use the 303 code as an initial identifier, not proof of interchangeability. Ask for a dimensioned drawing that shows the end’s outside diameter, curl dimensions, countersink, panel profile, and other seaming-related measurements. Compare those dimensions with the can-body flange and the setup requirements of your seamer.
The nominal conversion of 3 3/16 inches to 80.96 mm is a mathematical reference only; it does not establish the finished end’s manufacturing tolerance or usable seaming dimensions. If your existing tooling was designed for a particular supplier’s end, request a drawing comparison before substituting another product. Small profile differences can affect setup and seam quality, so validate a proposed change on the intended production line.
Specify the required tinplate grade and thickness in millimeters, along with coating or lacquer requirements for both product-contact and exterior surfaces. The appropriate specification depends on the beverage formulation, filling conditions, distribution environment, and local regulatory requirements. Do not assume that a coating used for one beverage or market will automatically be suitable for another.
Also state the opening style and tab requirements, if applicable. The score pattern, opening force expectations, tab design, and appearance requirements should be reviewed as part of the product specification. Where artwork or branding is involved, confirm print areas, colors, and decoration methods with the supplier before approving production materials.
Compatibility is not determined by diameter alone. A top end must be assessed with the can body, flange, seaming rolls, chuck, seamer settings, filling process, and intended product. A component that appears to fit dimensionally may still require equipment adjustment or qualification before routine production.
When changing end suppliers or specifications, plan a controlled line evaluation with your technical team. Review seam measurements and the acceptance criteria used at your facility, and follow your established quality procedures. We cannot determine compatibility from the “303” label alone; the drawing and a production-relevant evaluation are essential.
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Record the beverage, packaging format, target market, and expected storage and distribution conditions. Identify whether the end is for a new package design or a replacement for an existing part. If it is a replacement, collect the current end drawing and can-body specification where available.
A useful RFQ package can include one dimensioned drawing, three representative end samples when available, and forecast demand in pieces per year. Add required material and coating details, opening design, artwork requirements, packaging method, and destination market. State the required delivery schedule and whether you need samples or technical review before placing a production order.
Ask the supplier to confirm the proposed specification in writing and identify any differences from your current component. Review samples against the drawing, then conduct line trials under your own approved procedures before approving regular production. Keep the accepted drawing and sample reference with the purchase specification to reduce ambiguity in repeat orders.
Pricing for tinplate top ends can depend on the confirmed specification, order quantity, material and coating requirements, decoration, packaging, and delivery terms. Minimum order quantities and lead times are supplier- and project-specific, so they should be confirmed for the requested configuration rather than assumed from a general product description. For an accurate quotation, provide both the required quantity and your preferred delivery window.
Buyers can make sourcing discussions more efficient by separating mandatory requirements from options. For example, identify which dimensions and coatings are fixed, while noting whether artwork or packaging details can be finalized later. Ask the supplier to clarify quotation validity, sampling arrangements, production planning assumptions, and how specification changes may affect cost or schedule.
Evaluate a supplier on its ability to understand the full application, document the specification, and communicate clearly about fit and limitations. Request relevant product drawings and confirm how revisions are controlled. If your project requires specific quality, regulatory, or market documentation, describe those needs in the RFQ and verify what the supplier can provide; do not rely on unverified claims.
At Wanhua, we support B2B buyers evaluating beer can top ends by reviewing the requested size designation alongside the application and technical information provided. We can discuss the drawing, material and coating requirements, opening design, order quantity, and destination so that the quotation request is based on a defined product rather than a code alone. Availability, customization, MOQ, and lead time should be confirmed against the specific project.
For a faster assessment, send us your 303 end drawing or sample details, can-body information, intended beverage, annual demand, and target delivery date. If you are replacing an existing end, include the current supplier specification and note any known line constraints. Our team can then review the information and identify which points need confirmation before sampling or quotation.
A 303 tinplate beer can top end must be specified by its actual dimensions, material, coatings, opening design, and seaming requirements; the size code alone is not enough to establish fit. Although 303 may correspond to a nominal 3 3/16-inch or 80.96 mm designation in some conventions, buyers should verify the applicable drawing and standards with their supplier. Compatibility depends on the complete package and production setup, not only the end diameter.
To move forward, prepare a dimensioned drawing or representative sample, document the can body and line requirements, and request written confirmation of the proposed specification, MOQ, and lead time. Then evaluate samples and qualify the end on the intended line using your established procedures. Contact Wanhua with these details to begin a focused sourcing and quotation discussion.
Contact us to discuss your requirements of 303 Tinplate Beer Can Top Ends. Our experienced sales team can help you identify the options that best suit your needs.
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