96 well plate dimensions
One footprint, many heights. The numbers your readers, handlers, and seals are built around.
Every standard 96 well plate shares one footprint, which is why plates from different makers run on the same instruments. What changes between plates is height, well depth, and skirt, and those are the dimensions that decide fit.
The footprint never changes
The ANSI/SLAS standard footprint is 127.76 mm long by 85.48 mm wide. Plate readers, washers, seals, and liquid handlers are all built to it. If a plate is sold as a standard 96 well plate and does not meet the footprint, it will not run on automation, whatever the product page says.
Well pitch and the A1 corner
Wells sit on a 9 mm grid, 8 rows (A to H) by 12 columns. Well A1 is the indexing corner, marked on the drawing; instruments and software count from it. The blue corner notch in the drawing is the convention for showing A1 in diagrams, and most physical plates mark A1 with a chamfered corner, a printed label, or both.
Height is the variable
Total height runs from about 14 mm for a flat assay plate to over 40 mm for a 2 mL deep well plate. Height decides stacker capacity, whether a clamp or sealer closes over the plate, and how much headroom a handler needs. When a plate almost fits, height is usually the dimension to check, and the full stack height, plate plus seal or lid, is the number that matters.
Related guides
Common questions
Do all 96 well plates have the same dimensions?
The footprint and the 9 mm well pitch are standard. Height, well depth, well diameter at the top, and skirt shape vary by plate type and maker, which is why a plate can meet the footprint standard and still fail in a specific instrument.
What is the distance between wells on a 96 well plate?
9 mm center to center, in both directions. A 384 well plate quarters each 96 well cell, so its pitch is 4.5 mm on the same footprint.