# ZPL text is not centered

Source: https://openzpl.com/zpl/errors/text-not-centered/ (updated 2026-10-20)

ZPL centers text only inside a field block: ^FB with justification C centers each line within the block width, starting at the ^FO position. To center on the label, start at x = 0 and make the block as wide as the label, for example ^FO0,y^FB812,1,0,C at 203 dpi on a 4 inch label.

## What you see

Text that should sit in the middle of the label is to the left of center, or each line of an address starts at the same x instead of being centered. The guide line in the renders below marks the true center of a 4 inch label.

Block 600 dots wide: centered on x = 300:
```zpl
^XA
^FO406,0^GB1,406,1^FS
^FO0,60^A0N,50,50^FB600,1,0,C^FDSHIP TO^FS
^FO0,140^A0N,50,50^FB600,1,0,C^FDAUSTIN, TX 78701^FS
^XZ
```

Block as wide as the label:
```zpl
^XA
^FO406,0^GB1,406,1^FS
^FO0,60^A0N,50,50^FB812,1,0,C^FDSHIP TO^FS
^FO0,140^A0N,50,50^FB812,1,0,C^FDAUSTIN, TX 78701^FS
^XZ
```

## Why it happens

There are three usual causes, and each leaves a different mark:

- No ^FB at all. A plain ^FO field starts at its x position whatever its length. Every line starts at the same x, so lines of different length don't share a center.
- The block is not the label width. ^FB centers inside its own width. A 600 dot block starting at x = 0 centers text on x = 300, not on the middle of an 812 dot label. Every line is centered, but on the wrong axis.
- The block starts somewhere else. With ^FO40,y^FB733, the block covers 40 to 773 and its center is 406: fine. With ^FO100,y^FB812, the center moves 100 dots right.

The first case is what you get when you compute the x by hand for one string and then the data changes:

```zpl
^XA
^FO406,0^GB1,406,1^FS
^FO300,60^A0N,50,50^FDSHIP TO^FS
^FO300,140^A0N,50,50^FDAUSTIN, TX 78701^FS
^XZ
```

## The fix

Use ^FB and make the block cover the area you want to center on. For the whole label the block width is the label width in dots, and the block starts at x = 0. Label width in dots is inches × dpi: 812 at 203 dpi and 1218 at 300 dpi for a 4 inch label (see label sizes).

```zpl
^FO0,60^A0N,50,50^FB812,1,0,C^FDSHIP TO^FS
```

The 1 is the maximum number of lines. If the text can be longer than the block, raise it and the text wraps, each line centered. A \& in the data forces a line break.

## When the preview is centered but the print isn't

- Trailing spaces. They are part of the field data. The OpenZPL engine ignores them when centering; if your printer shifts the line left, strip spaces from the data before sending it.
- The printer's label width. If ^PW is missing, the printer uses its own setting. A block centered on 812 dots looks off on a printer configured for a narrower width. Put ^PW in the label.
- Label shift on the printer. A ^LS or a label top/left offset set on the printer moves everything; check the printer's configuration label.

**How do I right-align text in ZPL?** Use R as the justification of ^FB: ^FO0,y^FB792,1,0,R puts the end of each line 20 dots from the right edge of an 812 dot label.

**Why does my centered text wrap onto a second line I didn't ask for?** The text is wider than the block. Either make the font smaller, widen the block, or allow more lines; with one line allowed, the extra text is not printed where you expect.