The ZD421 is Zebra's current-generation desktop label printer, the successor to the well-loved ZD420. For anyone weighing a new printer against an older ZD420, the question is what actually changed, and the honest answer is that it's an evolution rather than a revolution, with a few meaningful upgrades and a lot of continuity.
What the ZD420 established
The ZD420 was Zebra's entry-level desktop printer, available in direct thermal and thermal transfer versions, and it built a reputation for reliable 4x6 label printing at moderate volume. It's still widely used and supported, which is why it remains a solid buy on the used market, as our ZD420 vs ZD620 guide notes.
What the ZD421 improves
The ZD421 brings a faster processor, improved connectivity options including better wireless support, and a refreshed design with a clearer media path and easier loading. None of these change the core job of printing 100 × 150mm labels, but they make setup and daily use a little smoother.
What stays the same
The fundamentals are unchanged: both print at 203 DPI or 300 DPI, both handle the same label widths and the standard 25mm core, and both use the same Zebra driver ecosystem. If you're printing shipping labels, the output quality and speed are essentially identical between the two.
Connectivity differences
The ZD421 offers a broader range of connectivity out of the box, including USB, Ethernet, Bluetooth and Wi-Fi options depending on the model. For a Shopify or Click & Drop workflow on a single computer, USB is plenty, but for shared use across a team, the ZD421's networking options are more flexible.
Driver and setup
Both printers use Zebra's ZDesigner driver, and the setup process is the same: install the correct driver, set the paper size to 100 × 150mm, and print at full size. Our Zebra driver guide applies to both, so moving from a ZD420 to a ZD421 involves no new learning curve.
Should you upgrade from a ZD420?
If your ZD420 is working, there's little reason to upgrade for shipping label printing alone, because the output is the same. Upgrade when the ZD420 is wearing out, when you need the ZD421's better wireless or networking, or when a new printer's warranty and support are worth more than squeezing more life from the old one.
Buying new vs used
For a first printer or a replacement, the ZD421 is the sensible new buy, while a well-priced used ZD420 remains a good value if you only need USB and moderate volume. Either way, they print the same 100 × 150mm shipping labels on the same 4x6 stock.
Frequently asked questions
Is the ZD421 worth upgrading to from a ZD420? For shipping labels alone, not really, the output is identical. Upgrade for better wireless, networking or when the ZD420 is wearing out.
What's the main difference between ZD420 and ZD421? The ZD421 has a faster processor, improved connectivity and easier media loading, but the print quality and label formats are the same.
Do the ZD420 and ZD421 use the same driver? Yes, both use Zebra's ZDesigner driver, so the setup process is identical.
Labels for every Zebra desktop
Both the ZD420 and ZD421 print our 100 × 150mm direct thermal labels cleanly, on the same 25mm core, with no reformatting.
Shop 4×6 Labels