> ## Documentation Index
> Fetch the complete documentation index at: https://docs.smartsend.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Zebra printer setup

> Configure paper size and label size on Zebra label printers, and read their status lights

Zebra label printers such as the ZD421d, ZD420d, ZD220, and GK420d need to be configured with the correct paper size before printing shipping labels. The paper size should be set to **102x192mm** or **100x150mm** depending on the labels you are using.

## Paper size on your computer

<Tabs>
  <Tab title="Mac">
    The Zebra label printers are installed on Mac like any other printer. Make sure to select the **Zebra ZPL Label Printer** driver.

    To configure the paper size:

    1. Open a [test label](/fundamentals/print-setup#test-labels) in the Preview app
    2. Select **Print**
    3. Under **Paper Size**, select "Manage Custom Sizes..."
    4. Press **+** to add a new size
    5. Specify the custom paper size:
       * Width: **102mm**
       * Height: **192mm**
       * Non-Printable Area: **User defined**
       * Top: **0 mm**, Right: **0 mm**, Bottom: **0 mm**, Left: **0 mm**
    6. Double-click the paper size to rename it to "102x192mm"

    Once configured, select that printer when printing shipping labels.
  </Tab>

  <Tab title="Windows">
    All Zebra label printers must be installed on Windows via the <Link href="https://www.zebra.com/gb/en/support-downloads/printer-software/printer-setup-utilities.html">Zebra Setup Utilities</Link> <Icon icon="arrow-up-right" size={12} />. The setup process will prompt for the paper size, which should be set to **102x192mm** or **100x150mm**.

    Once the printer is configured, select that printer when printing shipping labels.
  </Tab>
</Tabs>

## Printer models

### Zebra GK420d

<Warning>
  If the green status light flashes and nothing prints, the printer is probably paused. Press **Feed** once. The light should turn solid green, and the printer resumes printing.
</Warning>

<Tabs>
  <Tab title="Settings">
    The GK420d has no display. Everything you can set from the printer runs through the **Feed** button and the green status LED.

    With the printer switched on and the top cover closed, press and hold **Feed**. The green LED flashes in sequences — one flash, then two, then three, and so on. Release the button after the sequence you want and before the next one starts.

    <AccordionGroup>
      <Accordion title="Set the label size — two flashes" icon="ruler">
        Releasing after the second flash runs a standard auto media calibration. The printer detects the type and length of the labels you have loaded and adjusts its media sensors to match, feeding one to four labels while it works.

        Run it when you load a different label stock, or when the printer skips labels, prints across the gap between labels, or feeds blank labels.

        If auto calibration does not get it right, keep holding to the seventh flash instead. That runs a <Link href="https://docs.zebra.com/us/en/printers/desktop/gk420d-desktop-printer-user-guide/c-gk420d-ug-troubleshooting/t-gk420d-ug-manual-calibration.html">manual media calibration</Link> <Icon icon="arrow-up-right" size={12} />, a more extensive set of tests for stock the automatic routine cannot read.
      </Accordion>

      <Accordion title="Print a status page — one flash" icon="file-lines">
        Releasing after the first flash prints the configuration status label — the printer's current settings, including darkness, print speed and label size. Print one before you change any setting so you have a record of where you started, and again afterwards to confirm the change stuck.

        On a GK420d with the internal print server option, the lower half of this label also lists network settings such as the IP address, which is the quickest way to find the address of a printer you cannot reach. Networked models print an additional <Link href="https://docs.zebra.com/us/en/printers/desktop/gk420d-desktop-printer-user-guide/c-gk420d-ug-printer-options/c-gk420d-ug-zebranet-10-100-internal--wired--print-server-option/c-gk420d-ug-printer-network-configuration-status-label.html">network configuration label</Link> <Icon icon="arrow-up-right" size={12} /> as well.
      </Accordion>

      <Accordion title="Adjust darkness — six flashes" icon="circle-half-stroke">
        Releasing after the sixth flash prints a succession of barcode patterns at increasing darkness levels. Press **Feed** once when the pattern is clear and legible, and the printer keeps that darkness.

        This is the on-printer alternative to the [Print Quality Assistant](/troubleshooting/print-quality#finding-the-right-settings-on-a-zebra-printer) when you have no computer or phone to hand.
      </Accordion>
    </AccordionGroup>

    For the full list of sequences, see Zebra's <Link href="https://docs.zebra.com/us/en/printers/desktop/gk420d-desktop-printer-user-guide/c-gk420d-ug-troubleshooting/r-gk420d-ug-feed-button-modes.html">Feed button modes</Link> <Icon icon="arrow-up-right" size={12} />.

    <Warning>
      Holding **Feed** while you switch the printer **on** is a different mode and enters firmware download. Power the printer up first, then hold **Feed**.
    </Warning>
  </Tab>

  <Tab title="Status">
    The GK420d has a single status light next to the **Feed** button. Its color and flash pattern tell you what the printer is doing.

    | Status light                       | Meaning                                                                                             | What to do                                                                                                                                            |
    | ---------------------------------- | --------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------- |
    | Off                                | The printer has no power.                                                                           | Check that the printer is switched on and that the power cable is connected at both ends.                                                             |
    | Solid green                        | The printer is on and ready.                                                                        | Nothing.                                                                                                                                              |
    | Flashing green                     | The printer is receiving data.                                                                      | Wait. The light turns solid green when all data has been received.                                                                                    |
    | Double flashing green              | The printer is paused.                                                                              | Press **Feed** to resume printing.                                                                                                                    |
    | Solid amber                        | The printer failed its power-on self-test, has a memory error, or the printhead needs to cool down. | Switch the printer off and on. If the light stays amber, switch it off for at least five minutes. If it still stays amber, the printer needs service. |
    | Flashing amber                     | The printhead is too hot.                                                                           | Wait. The printer resumes automatically when the printhead has cooled down.                                                                           |
    | Flashing red                       | The labels have run out, or the top cover is open.                                                  | Load new labels or close the top cover, then press **Feed**.                                                                                          |
    | Alternately flashing green and red | The printer needs service.                                                                          | Contact your Zebra reseller.                                                                                                                          |
    | Flashing red, red, green           | The printhead or motor has failed.                                                                  | Contact your Zebra reseller.                                                                                                                          |
    | Flashing red, amber, green         | The printer is defragmenting its memory.                                                            | Wait, and do not switch the printer off.                                                                                                              |

    For details, see Zebra's <Link href="https://docs.zebra.com/us/en/printers/desktop/gk420d-desktop-printer-user-guide/c-gk420d-ug-troubleshooting/r-gk420d-ug-status-light-descriptions.html">status light descriptions</Link> <Icon icon="arrow-up-right" size={12} />.
  </Tab>
</Tabs>

### Zebra ZD420d and ZD421d

<Warning>
  If the **PAUSE** indicator is lit, the printer is paused. Press the **PAUSE** button once to resume printing.
</Warning>

<Tabs>
  <Tab title="Settings">
    These models use button combinations rather than flash counts. Wait until the printer is ready — the **STATUS** indicator lit solid green — before pressing anything.

    <AccordionGroup>
      <Accordion title="Set the label size — PAUSE + CANCEL" icon="ruler">
        With labels loaded and the top cover closed, press and hold **PAUSE** and **CANCEL** together for two seconds, then release. This is SmartCal media calibration: the printer feeds and measures several labels and adjusts its media sensing levels. The **STATUS** indicator returns to solid green when it succeeds.

        Run it when you load a different label stock. You do not need to repeat it for another roll of the same stock — a press or two of **FEED** is enough to resynchronise the printer.

        See Zebra's instructions for the <Link href="https://docs.zebra.com/us/en/printers/desktop/zd421-and-zd621-desktop-printers-user-guide/c-zd620-420-setup/c-zd421-zd621-ug-smartcal-media-calibration.html">ZD421 and ZD621</Link> <Icon icon="arrow-up-right" size={12} /> or the <Link href="https://docs.zebra.com/us/en/printers/desktop/bm-zd620-and-zd420-desktop-printers-user-guide-ditamap/c-zd620-420-setup/t-zd620-420-running-a-smartcal-media-calibration.html">ZD420 and ZD620</Link> <Icon icon="arrow-up-right" size={12} />.
      </Accordion>

      <Accordion title="Print a status page — FEED + CANCEL" icon="file-lines">
        Press and hold **FEED** and **CANCEL** together for two seconds, then release. The printer prints both the printer configuration report and the network configuration report, then returns to ready.

        The network report covers the Ethernet, Wi-Fi and Bluetooth settings, so this is the quickest way to read the IP address of a printer you cannot reach from your computer. The printer report gives you the current darkness, speed and label size.

        See Zebra's instructions for the <Link href="https://docs.zebra.com/us/en/printers/desktop/zd421-and-zd621-desktop-printers-user-guide/c-zd421-zd621-ug-tools/r-mlk-ug-printer-diagnostics/t-zd620zd420-ug-printing-the-printer-and-network-configuration-reports.html">ZD421 and ZD621</Link> <Icon icon="arrow-up-right" size={12} /> or the <Link href="https://docs.zebra.com/us/en/printers/desktop/bm-zd620-and-zd420-desktop-printers-user-guide-ditamap/c-zd620-420-tools/c-zd200t-ug-printer-diagnostics/t-zd620zd420-ug-printing-the-printer-and-network-configuration-reports.html">ZD420 and ZD620</Link> <Icon icon="arrow-up-right" size={12} />.
      </Accordion>

      <Accordion title="Compare darkness settings — FEED at power-on" icon="circle-half-stroke">
        The print quality report prints a range of test labels at speeds and darkness levels above and below the printer's current settings, so you can pick the best one by eye.

        1. Print a configuration report with **FEED** + **CANCEL** so you know the current darkness value.
        2. Switch the printer off.
        3. Press and hold **FEED** while you switch the printer on. Release **FEED** when the status indicator is the only indicator lit.
        4. Find the label that prints best. Bars and spaces should be distinct and the text complete — not so dark that small text fills in, and not so light that the bars lose definition.
        5. Add the relative darkness value printed on that label to your current darkness value, and set the result on the printer.

        See <Link href="https://docs.zebra.com/us/en/printers/desktop/zd421-and-zd621-desktop-printers-user-guide/c-zd421-zd621-ug-tools/r-mlk-ug-printer-diagnostics/c-zd410d-ug-perform-a-print-quality-report-feed-self-test/t-zd421-zd621-ug-printing-a-print-quality-report.html">printing a print quality report</Link> <Icon icon="arrow-up-right" size={12} />.
      </Accordion>
    </AccordionGroup>
  </Tab>

  <Tab title="Status">
    These models have five indicator lights above the buttons: **STATUS**, **PAUSE**, **DATA**, **SUPPLIES**, and **NETWORK**. The combination of lit indicators tells you what the printer is doing.

    | Indicators                          | Meaning                        | What to do                          |
    | ----------------------------------- | ------------------------------ | ----------------------------------- |
    | **STATUS** solid green              | The printer is on and ready.   | Nothing.                            |
    | **PAUSE** amber                     | The printer is paused.         | Press **PAUSE** to resume printing. |
    | **DATA** flashing green             | The printer is receiving data. | Wait.                               |
    | **STATUS** red and **SUPPLIES** red | The labels have run out.       | Load new labels.                    |
    | **STATUS** red and **PAUSE** amber  | The top cover is open.         | Close the top cover.                |

    For the full list, including network indicators, see Zebra's indicator light patterns for the <Link href="https://docs.zebra.com/us/en/printers/desktop/zd421-and-zd621-desktop-printers-user-guide/controls-and-indicators/meaning-of-the-indicator-light-patterns/status-typical-operating-conditions.html">ZD421 and ZD621</Link> <Icon icon="arrow-up-right" size={12} /> or the <Link href="https://docs.zebra.com/us/en/printers/desktop/bm-zd620-and-zd420-desktop-printers-user-guide-ditamap/c-zd620-420-controls-and-indicators/r-zd620-420-meaning-of-the-indicator-light-patterns.html">ZD420 and ZD620</Link> <Icon icon="arrow-up-right" size={12} />.
  </Tab>
</Tabs>

<Note>
  Calibrating the label size on the printer is not the same as setting the paper size on your computer. Both need to match your labels, so work through [Paper size on your computer](#paper-size-on-your-computer) above as well.
</Note>