What is a microplate?
A flat plate with wells in a grid, each well a small dish or tube that shares its walls with its neighbors, built to one standard footprint so any instrument can hold any plate.
A microplate (also called a microtiter plate or well plate) is a flat plastic plate containing many small wells arranged in rows and columns. Each well holds a sample, a culture, or a reaction, and because every microplate shares the same outside dimensions, plate readers, washers, shakers, incubators, and robots can all handle the same plate without adjustment.
The standard underneath every format
The ANSI/SLAS standards fix the footprint at 127.76 by 85.48 mm and define how wells are positioned from the plate corner. Well counts double and halve along the family: 6, 12, 24, 48, 96, 384, 1536. The 12 well plate sits at 3 rows of 4 with wells on a 26 mm grid. At this end of the family the wells stop looking like tubes and start looking like what they are used as: small culture dishes that happen to share a frame.
The 12 well plate in numbers
- Wells: 12, in 3 rows (A to C) by 4 columns
- Well spacing: 26 mm center to center
- Footprint: 127.76 by 85.48 mm, the ANSI/SLAS standard
- Culture well: about 22 mm across, 3.8 cm2 growth area, 1 to 2 mL working volume
- Deep well: square wells in the 5 mL class, polypropylene
Why the big-well formats exist
Miniaturization is not free. Every halving of well size buys throughput with material: fewer cells, less extract, worse access. The 12 well format exists for the work that cannot pay that price: cultures that must be seen and handled, inserts that need a well to hang in, explants that need a dish. Its throughput is twelve, and for that work twelve well-chosen wells beat ninety-six compromised ones.
Who uses 12 well plates
- Cell biology labs: culture with harvest, imaging, and transfection at useful scale.
- Co-culture and transport studies: insert wells as two-compartment systems.
- Tissue and developmental labs: explants and organotypic culture that need dish-sized wells.
- Analytical labs: parallel digestion and extraction in deep well format.
Related guides
Common questions
Is a 12 well plate a microplate?
Yes. A microplate is any plate in the standard footprint family, from 6 to 1536 wells. The 12 well plate is a full member: same outside dimensions, same instrument compatibility, wells on the 26 mm grid defined for the format.
What is the difference between a 12 well plate and a 24 well plate?
Well count and well size. A 24 well has twice the wells at half the growth area (1.9 vs 3.8 cm2). The 12 well gives each culture room to be imaged, harvested, and fitted with inserts; the 24 trades that room for more conditions per plate.
Why are microplates all the same size?
Because instruments are built once and plates are bought forever. The shared ANSI/SLAS footprint means a reader, washer, or robot arm made this year handles plates from any maker, and a protocol written around one brand survives switching suppliers.
What does 3 by 4 mean on a 12 well plate?
The well layout: 3 rows lettered A to C and 4 columns numbered 1 to 4. Wells are named by row and column, so B3 is the well in row B, column 3. Plate maps and plate map makers use the same addresses.
Are all 12 well plates the same?
No. They share a footprint and grid, but differ in surface treatment, well bottom shape, material, and whether they are built for inserts. Fit and function follow those details, not the well count.