What is a microplate?
The general idea, explained from the 384 well end of the range, where the wells are small and the trade-offs are sharp.
A microplate (also called a microtiter plate or a multiwell plate) is a flat, usually rectangular plastic plate holding a grid of small, separate wells, each one a miniature test tube. One plate therefore carries dozens or hundreds of independent samples, reactions, or cell cultures, all on the same standard footprint, 127.76 mm by 85.48 mm under the ANSI/SLAS standards, so the plate moves between pipettes, liquid handlers, incubators, and readers as a single unit.
This site covers the 384 well member of the family: 16 rows by 24 columns of wells on a 4.5 mm pitch, in the footprint the 96 well format made standard. The general guide to what a microplate is lives on the 96 well plate guide; this page answers the same question from the high-density end.
Why 384 wells exist
The microplate idea scales by shrinking wells. Gyula Takatsy machined the first plates in 1951 with 96 wells; as readers and liquid handlers improved, the same footprint was divided finer, 96 to 384 to 1,536, each step quartering the volume per well. 384 is where most screening settled: four 96 well plates consolidate into one, reagent per data point drops to the 20 to 50 microliter range, and a handler run finishes in a fraction of the deck time. The wells stay big enough for cells and for ordinary multichannel pipettes, which 1,536 does not promise.
Who uses 384 well plates, and for what
- High throughput screening: testing compound libraries against a target, where the number of data points per plate is the economics of the whole program.
- Compound storage and replication: deep well 384 plates holding libraries and working copies in the 100 microliter class.
- Genomics and sequencing prep: PCR 384 plates for library preparation and qPCR at small volumes.
- Miniaturized cell assays: endpoint viability and dose response work where a few thousand cells per well is enough.
- Core facilities: consolidating 96 well work into fewer plates, fewer seals, and shorter handler runs.
What changes at 384
Three things, all of them consequences of small wells. Automation becomes the assumption: a 5 microliter dispense error that 96 forgives is a failed well at 384, and nobody pipettes a full 384 plate well by hand. Evaporation moves from nuisance to result: perimeter wells dry first, and the perimeter is 76 of the 384 wells, a fifth of the plate, so sealing, humidity, and short open times are part of the format. Precision is a plate property: well-to-well spacing, wall thickness, and plate flatness stop being manufacturing details and start deciding whether a run reads cleanly. The 384 vs 96 comparison works through the cost and handling trade-off in full.
Microplate words, sorted
Microplate, microtiter plate, microwell plate, multiwell plate: four names for the same object, used interchangeably in catalogs and papers. A 384 plate: a microplate with 384 wells, named by its count. A plate reader: the instrument that measures the plate, bought separately and matched to the plate format. Well address: the row letter and column number of a well, A1 to P24 on a 384 plate, the coordinate every result hangs on. The full plain-language treatment, including well shapes, colors, materials, and handling pitfalls, is the what is a microplate page on the 96 well guide.
The 384 well format in numbers
| Measure | 384 well format |
|---|---|
| Rows x columns | 16 x 24 |
| Well pitch | 4.5 mm |
| Footprint | 127.76 x 85.48 mm (ANSI/SLAS), same as 96 well |
| Working volume | About 5 to 120 microliters, by type |
| Total (brim) volume | About 40 microliters (PCR) to 300 microliters (deep well), by type |
| Growth area per well | About 0.06 cm2 |
Volumes and growth areas are working ranges for common plates; confirm the exact figure on the specific plate before a regulated run.
Related guides
Common questions
Is a 384 well plate a microplate?
Yes. Microplate is the family name for every format on the standard footprint, from 6 wells to 1,536. A 384 well plate is the high-density member most screening labs use: 16 rows by 24 columns on a 4.5 mm pitch.
Why do 384 well plates exist?
To cut cost per data point. Dividing the standard footprint into four times the wells quarters the reagent per assay and consolidates four 96 well plates into one, once readers and liquid handlers could aim at wells on a 4.5 mm pitch accurately.
Can you use a 384 well plate for cell culture?
Yes, for miniaturized endpoint assays and screening. Each well offers about 0.06 cm2 of growth area, roughly a fifth of a 96 well, so seeding runs to several thousand cells per well, and evaporation at the edges is the practical limit on long cultures. Routine culture still lives at 96 and below.
What is the difference between a microplate and a microwell plate?
Nothing. Microplate, microwell plate, microtiter plate, and multiwell plate are four names for the same object: a flat plate of addressed wells on the standard footprint. Catalogs and papers use them interchangeably.
How are wells identified on a 384 well plate?
By row letter and column number: 16 rows, A to P, and 24 columns, 1 to 24, so every well has an address such as P24, the last well. The notched corner marks A1, the first.