Glass Petri Dish Size Guide

A useful size specification identifies the complete set. For example, a “90 mm glass Petri dish” in this range has a 90 mm bottom diameter, an 18 mm bottom height, a 97 mm cover diameter and a 16 mm cover height. Writing only “90 × 18 mm” leaves the cover undefined and can create receiving, storage and replacement problems. Start with the working surface and sample volume, then check cover clearance, stack height, carton quantity and the handling method used by the laboratory.

What each glass Petri dish dimension means

Bottom diameter describes the outside diameter of the dish body and is the number normally used to identify the size family. Cover diameter describes the matching lid; it must be wider so it can sit over the bottom. Bottom height affects usable depth and handling, while cover height affects clearance, overall stack height and fit. These four values should appear as separate fields on a drawing, specification sheet or purchase order.

The nominal diameter is not a substitute for dimensional tolerance. If the dish must fit an instrument, holder, incubator rack or automated imaging system, provide the maximum permitted outside dimensions and request a configuration-specific tolerance. No tolerance should be inferred from the nominal values below.

Standard 60–200 mm size comparison

The following table is based on the current GlassPetriDish standard product data. It is an original purchasing view because it places all four dimensions and the carton quantity in one comparison.

Bottom and cover dimensions are shown separately to prevent ordering ambiguity. Wall thickness, dimensional tolerance, exact MOQ and lead time are available on request and depend on the final product configuration.

A smaller dish is not automatically the better economical choice. Although more 60 mm sets fit in a carton, a small usable area may increase the number of dishes needed for a method. Conversely, a 200 mm dish offers a larger working area but requires more bench space, wider storage and more protective packaging per set. The economical unit is the size that meets the method without unnecessary area or handling.

How to choose the right size

Size recommendations by purchasing situation

60 and 75 mm: consider these where compact handling and a smaller working area are acceptable. The listed carton quantities are 300 and 180 sets respectively, so buyers should confirm storage and inspection capacity as well as unit demand.

90 and 100 mm: these are useful comparison points for laboratories seeking a mid-range footprint. They are not interchangeable: the 90 mm bottom uses a 97 mm cover, while the 100 mm bottom uses a 108 mm cover. Both list 120 sets per carton, but their heights differ.

120 and 150 mm: use these when a larger working area or deeper bottom is needed. The 120 mm option has a 25 mm bottom height and 60 sets per carton; the 150 mm option has a 30 mm bottom height and 48 sets per carton.

180 and 200 mm: these are large standard options and require deliberate bench, rack and packaging planning. If a standard diameter does not meet the application, use the custom glass Petri dish review process rather than selecting a near size without validation.

Common specification mistakes

• Using one diameter: correct it by listing bottom and cover diameters separately.
• Ignoring height: record both component heights and check stack clearance.
• Assuming material from size: request material confirmation for the selected configuration.
• Assuming a carton quantity is an MOQ: carton quantity and minimum order quantity are different commercial fields.
• Approving from a web table alone: use samples or a signed specification when fit is critical.

How to approve supplier dimensions before a production order

Turn the web table into a controlled approval process. First, issue an RFQ that repeats every required dimension and identifies which measurements are nominal. Second, request a supplier drawing or specification and compare it line by line. Third, receive representative samples and measure them with calibrated equipment suitable for the required decision. Fourth, check the dish in the actual rack, cabinet, work area or secondary package. Finally, record the accepted configuration and revision on the purchase order.

Sampling is especially important when a cover from one lot could be mixed with a bottom from another. A cover that appears acceptable on one sample may have too much movement or insufficient clearance when lot variation is considered. The buyer should define how many pieces are checked, which points are measured, how the dish is oriented and what happens when a sample falls outside an agreed criterion. Website dimensions alone cannot replace that agreement.

Distributors should also protect size identity through packaging and inventory. Use a distinct SKU, barcode or carton mark for every complete set. Do not reuse an ambiguous label such as “large glass dish” across 150, 180 and 200 mm items. When a buyer requests a replacement cover, verify the bottom specification and lot rather than assuming that nominal diameter alone guarantees interchangeability.

Size selection summary for purchase approval

The final choice should connect method need to a controlled product identity. Record why the selected diameter is necessary, which bottom height is acceptable, what cover clearance is required and how many complete sets are needed per operating period. Then convert demand into cartons using the listed packing quantity, while keeping MOQ as a separate supplier-confirmed field.

If two sizes both appear workable, compare samples under the same method and document the deciding factor. It may be usable area, equipment clearance, handling, packaging density or inspection time. This short decision record prevents a later buyer from substituting a near size because the original reason was never written down. It also gives the supplier a specific question to answer when a configuration or pack changes.

Return to the complete glass Petri dish product range to review material, packaging and reuse information. For material-dependent processing, continue with the borosilicate versus soda-lime comparison.