Every iMac carries a unique model number that encodes its generation, display size, processor family, and manufacturing year. Understanding this code helps you identify configuration, compatibility, and market value at a glance.
Below you will find a quick reference table, detailed explanations of key iMac model number topics, answers to common questions, and practical takeaways.
| Model Number | Display Size | Processor Generation | Typical Year |
|---|---|---|---|
| iMac20,1 | 27-inch 5K | 8th Gen Intel Coffee Lake | 2020 |
| iMac19,1 | 27-inch 5K | 9th Gen Intel Coffee Lake | 2019 |
| iMac18,1 | 21.5-inch 4K | 8th Gen Intel U series | 2018 |
| iMac21,3 | 24-inch 4.5K | Apple M1 | 2021 |
| iMac23,2 | 24-inch 4.5K | Apple M3 | 2023 |
How to Locate the Model Number on Your iMac
You can find the official model number by opening the About This Mac dialog on your desktop. Click the Apple menu, choose About This Mac, and the model identifier appears directly below the screen name.
Alternatively, look at the physical back label on the iMac, or check the original packaging where a small barcode area includes the short model number used for replacement and parts identification.
This number is essential when you contact Apple support, book repairs, or shop for compatible accessories, so writing it down in your records prevents mismatches.
Why the Model Number Differs from the Marketing Name
Apple often markets iMacs by year and size, such as 2020 27-inch iMac, while the technical model number uses a YY,N format that encodes hardware specifics more precisely.
The marketing name can refer to multiple model numbers when Apple offers different processor tiers or graphics configurations within the same external design.
Always confirm the exact model number before purchasing RAM, storage, or upgrade parts, because visually identical iMacs may have different component compatibility.
Decoding the Structure of iMac Model Numbers
The first two digits indicate the production year and generation, while the suffix after the comma identifies the specific SKU, display type, and component choices.
Small changes in the suffix can mean different memory controllers, glass thickness, or compatibility with particular docks and stands, even when the screen size appears the same.
Technicians and parts resellers rely on this number more than the retail name to ensure they order the correct display assembly or internal frame.
Model Numbers and Repair Relevance
During repairs, service providers request the model number to verify part numbers for display cables, hinges, stands, and logic board assemblies.
Using a mismatched part based on an incorrect assumption about the iMac model number can lead to longer downtime, additional shipping costs, or the need to return incorrect components.
Keeping a record of your iMac model number alongside serial and purchase date simplifies warranty checks, AppleCare eligibility, and third-party repair estimates.
Practical Takeaways for Working with iMac Model Numbers
- Check the model number in About This Mac before purchasing parts or accessories to guarantee compatibility.
- Record the full YY,N code alongside your serial number for warranty, insurance, and repair reference.
- Use the model number, not just screen size, when comparing technical specifications between iMac generations.
- Confirm the exact model number when seeking repairs or replacement parts to avoid mismatched components.
FAQ
Reader questions
What do the first two digits in an iMac model number actually represent?
The first two digits encode the production year and generation; for example, 21 refers to 2021, while 19 indicates 2019, helping identify the iMac model year quickly.
Can two iMacs with the same display size have different model numbers?
Yes, identical display sizes can correspond to different model numbers when Apple offers different processors, graphics, or memory configurations within the same external chassis.
Why does my iMac box show a different model number than About This Mac?
The box label often reflects the original shipped SKU, while About This Mac shows the runtime model number; minor suffix variations can indicate configuration differences without affecting the core product identification.
Is the iMac model number useful when determining upgrade compatibility?
Yes, the model number determines socket type, memory generation, supported RAM capacity, and compatible accessories such as docks, so it is critical for planning upgrades accurately.