How to center text in ZPL

Published: 2026-10-02

ZPL places a field at the ^FO position you give it and prints the text to the right. There is no "center" switch for a plain text field, which is why centered titles drift left or right when the text changes. There are two reliable ways around it.

1. Let the printer center it: ^FB with C

A ^FB field block has a width and a justification. Start the field at the left edge, make the block as wide as the label, allow one line, and set justification to C. The printer centers the text with its own font metrics, so the result is right on the paper whatever the text is.

^XA
^PW812
^FO0,40^A0N,50^FB812,1,0,C^FDSHIP TO^FS
^XZ

Open this label in the ZPL viewer →

^FB812,1,0,C means: 812 dots wide (the full 4-inch label at 203 dpi), at most 1 line, no extra line spacing, centered. To center inside a box instead of the whole label, start ^FO at the box's left edge and use the box width. Keep the line count at 1 for titles: text longer than the block wraps, and extra lines print on top of the last one.

2. Compute the x position from the measured width

Sometimes a block is not an option: rotated text, a field you position with ^FT, or a layout tool that needs the width up front. Then the x position is (label width − text width) / 2, and the only unknown is the text width in dots. Our API measures it with the same engine the preview uses:

curl -s https://labelixa.com/v1/text/measure \
  -H "Content-Type: application/json" \
  -d '{"text": "SHIP TO", "font": "0", "height": 50, "label_width": 812}'

The answer carries width_dots, center_x (the ^FO x to use) and, when you pass block_width, the number of lines the text needs. The font is our preview font calibrated to Zebra font 0, so a printer's ROM font can differ by a few dots; the response says so. For pixel-exact centering on paper, prefer method 1.

Check it before you print

Paste the code into the ZPL viewer and change the text: a centered block stays centered, a fixed ^FO does not. If the text overflows instead, see ZPL text runs off the label.

Frequently asked questions

How do I center text in ZPL?

Start the field at the left edge and wrap it in a ^FB block as wide as the label with C justification, for example ^FO0,40^A0N,50^FB812,1,0,C^FDtext^FS on a 4-inch 203 dpi label. The printer then centers it with its own font metrics.

Can I calculate the x position instead?

Yes: x = (label width − text width) / 2. The text width in dots can be measured with POST /v1/text/measure, which also returns center_x. It measures with a preview font calibrated to Zebra font 0, so a printer's ROM font can differ by a few dots.

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