Comparison

Zebra ZD621 vs ZD421: which 4-inch desktop printer?

Same width, ribbons and buttons. The ZD621 adds speed, built-in Ethernet and serial, a media dancer and an optional touch display; the ZD421 offers a ribbon cartridge.

5 min Difficulty: Easy Updated: By SCANSHOP team
Best for most users
Zebra ZD621t Desktop Label Printer (ZD6A042-30EF00EZ)
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Alternative
Zebra ZD421t Desktop Label Printer (ZD4A042-30EE00EZ)
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In this guide

    The ZD621 and ZD421 are 4-inch desktop printers from the same Zebra platform and share one user guide. Both print up to 104 mm wide, take 74 m or 300 m ribbon rolls and use the same buttons and procedures. The ZD621 is the premium model: it prints faster, has Ethernet and serial ports built in, a media dancer for print quality and an optional colour touch display. The ZD421 is the lighter, lower-specified choice and the only one with a ribbon cartridge version.

    ZD621 ZD421
    Versions ZD621d direct thermal, ZD621t ribbon roll, ZD621R RFID, linerless and healthcare models ZD421d direct thermal, ZD421t ribbon roll, ZD421c ribbon cartridge, healthcare models
    Resolution 203 dpi; 300 dpi optional Same
    Max print speed 203 mm/s (8 ips) at 203 dpi; 152 mm/s (6 ips) at 300 dpi 152 mm/s (6 ips) at 203 dpi; 102 mm/s (4 ips) at 300 dpi
    Max print width 104 mm at 203 dpi; 108 mm at 300 dpi Same
    Media width 15–108 mm (direct thermal), 15–118 mm (thermal transfer) 15–108 mm (ZD421d), 15–112 mm (ZD421t), 15–118 mm (ZD421c)
    Media roll Up to 127 mm diameter; 12.7 or 25.4 mm core, 38.1–76.2 mm with adapters Same
    Ribbon 74 m or 300 m roll, 33.8–109.2 mm wide ZD421t: 74 m or 300 m roll, 33.8–109.2 mm wide. ZD421c: 74 m cartridge
    Media dancer Yes No
    Controls 5 status lights, 3 buttons; optional 4.3-inch colour touch display 5 status lights, 3 buttons, no display
    Standard ports USB 2.0, USB host, Ethernet 10/100, RS-232 serial, Bluetooth Low Energy for the setup app USB 2.0, USB host, Bluetooth Low Energy for the setup app
    Optional connectivity Wi-Fi 6 (802.11ax) with Bluetooth 5.3, or Wi-Fi 5 (802.11ac) with Bluetooth Same wireless options, plus Ethernet or serial modules
    RFID UHF RFID on the ZD621R Not available
    Options Dispenser, cutter, 2750 mAh battery Same
    Memory 512 MB flash, 256 MB SDRAM Same
    Size and weight, thermal transfer (L × W × H) 267 × 202 × 192 mm, 2.5 kg 267 × 202 × 189 mm, 2.05 kg (ZD421t)
    Size and weight, direct thermal (L × W × H) 221 × 177 × 151 mm, 1.6 kg 220.8 × 177.5 × 150.7 mm, 1.35 kg
    Operating temperature 4.4–41 °C Same

    Figures from Zebra's ZD600 Series and ZD421 spec sheets; speeds are maximums.

    Choose the ZD621 if
    • You print large batches and want up to 203 mm/s
    • You need Ethernet or a serial port out of the box, for example for a network or an older system
    • Several people use the printer and a touch display with wizards and plain-text alerts helps them
    • You want the media dancer that Zebra adds for print quality
    • You need RFID or linerless labels
    Choose the ZD421 if
    • The printer sits next to one PC on USB, and 152 mm/s is fast enough
    • You want the quick-change ribbon cartridge of the ZD421c
    • You may add Ethernet, serial or Wi-Fi later, as you need them
    • A lighter printer matters

    What both printers share

    Zebra documents the ZD421 and ZD621 in one user guide. Labels and 74 m or 300 m ribbon rolls load the same way, and the buttons work the same: SmartCal is PAUSE + CANCEL, the configuration report FEED + CANCEL. The five status lights have the same meanings, both speak ZPL and EPL, and both take the same kinds of options: battery, dispenser and cutter. Ribbon rolls fit both the ZD621t and the ZD421t; cartridges fit only the ZD421c.

    Both can ship with Zebra's extra EU security when bought in Europe from 1 August 2025; affected models then need a Protected Mode password during setup, as explained in our ZD621 setup guide.

    Where they really differ

    Speed and print quality

    At 203 dpi the ZD621 prints up to 203 mm/s against 152 mm/s on the ZD421, about a third faster. It also has a media dancer, which Zebra lists as a print quality feature; the ZD421 has none.

    Display and connectivity

    The ZD621 can have a 4.3-inch colour touch display with menus, setup wizards and alerts in plain text; the ZD421 always works with lights and buttons only. Every ZD621 has Ethernet and serial ports; on the ZD421 they are add-on modules.

    Zebra ZD621/ZD421 Desktop Printers

    Video: Zebra Technologies

    Compare the models in our shop: ZD621t 203 dpi, ZD621d 203 dpi, ZD421t 203 dpi and ZD421d 203 dpi. More guides: ZD621 and ZD421.

    Frequently asked questions

    Is the ZD621 faster than the ZD421?

    Yes. At 203 dpi the ZD621 prints up to 203 mm/s and the ZD421 up to 152 mm/s. At 300 dpi it is 152 against 102 mm/s.

    Do the ZD621t and ZD421t use the same ribbons?

    Yes. Both take 74 m and 300 m ribbon rolls from 33.8 to 109.2 mm wide. Only the ZD421c uses ribbon cartridges.

    Does the ZD421 have a touch display?

    No. The ZD421 has five status lights and three buttons. Of the two, only the ZD621 offers a colour touch display.

    Can I add Ethernet to the ZD421 later?

    Yes. Ethernet and serial are field-installable modules for the ZD421. On the ZD621 both are built in.

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