Change rulers and measurement units
You
can change measurement units for the on‑screen rulers and for use
in panels and dialog boxes; you can also change these settings at
any time and temporarily override the current measurement
units as you enter a value. By default, rulers begin measuring from
the upper-left corner of a page or spread. You can change this by
moving the zero point.
Changing the measurement units doesn’t move guides, grids, and
objects, so when ruler tick marks change, they might not line up
with objects aligned to the old tick marks.

Rulers in a document window
- A.
- Labeled tick marks
- B.
- Major
tick marks
- C.
- Minor tick marks
You
can set up different measurement systems for horizontal and vertical
rulers. The system you select for the horizontal ruler
governs tabs, margins, indents, and other measurements. Each spread
has its own vertical ruler; however, all vertical rulers use the
same settings you specify in the Units & Increments
preferences dialog box.
The default units
of measure for the rulers are picas (a pica equals 12 points). However,
you can change custom ruler units and control where the major tick
marks appear on a ruler. For example, if you change the custom ruler
units for the vertical ruler to 12 points, a major ruler increment
appears every 12 points (if such display is possible in the current
magnification). The tick mark labels include your customized major
tick marks, so when the ruler reads 3 in the same example, it marks
the third instance of the 12‑point increment, or 36 points.

Vertical ruler using inches (left), and custom 12‑point increments
(right)

Setting custom ruler increments in the vertical
ruler is useful for lining up a ruler’s major tick marks with a
baseline
grid.
Show or hide rulers
In
Normal View Mode (View > Screen Mode > Normal),
choose View > Show Rulers or Hide Rulers.
Change measurement units and rulers
Choose
Edit > Preferences > Units & Increments
(Windows) or InDesign > Preferences > Units
& Increments (Mac OS).
To change the origin of the zero point, in the Origin menu
under Ruler Units, do one of the following:
To set
the ruler origin at the top-left corner of each spread, choose Spread. The
horizontal ruler measures across the entire spread.
To set the ruler origin at the top-left corner of each page,
choose Page. The horizontal ruler starts at zero for each page in
a spread.
To set the ruler origin for multipage spreads on the top-left
corner of the leftmost page, as well as at the top of the binding
spine, choose Spine. The horizontal ruler measures from the leftmost
page to the binding edge; and from the binding spine to the rightmost
page.
To change the measurement system used for rulers, dialog
boxes, and panels, choose the desired system for Horizontal and
Vertical, or choose Custom and type the number of points at which
you want the ruler to display major tick marks.
If you specify
a measurement system other than points, the Increment Every baseline
grid value is still displayed in points. This makes it easier to
match text size and leading values, which are displayed in points.
To change the value you want used for calculating points,
specify the desired point size per inch for Points/Inch.
Set any of the following Keyboard Increments:
- Cursor Key
- Controls the increment for the arrow keys when nudging objects.
- Size/Leading
- Controls the increment for increasing or decreasing the point size
or leading using the keyboard shortcuts.
- Baseline Shift
- Controls the increment for shifting the baseline using the keyboard
shortcuts.
- Kerning/Tracking
- Controls the increment for kerning and tracking using the keyboard
shortcuts.
Click OK.

You can also change ruler units by right-clicking
(Windows) or Control-clicking (Mac OS) a ruler and choosing
the units from the context menu. By right-clicking or Control-clicking
at the intersection of the horizontal and vertical rulers, you can change
the ruler units for both rulers at the same time.
Override default measurement units
You can specify a unit of measurement
that is different from the default.

Highlight the existing value in a panel or dialog box,
and type the new value using the notation in the following table:
To specify:
|
Type these letters after the value:
|
Examples
|
Result
|
Inches
|
i
in
inch
"
|
5.25i
5.25in
5.25inch
5.25”
|
5 1/4 inches
|
Millimeters
|
mm
|
48mm
|
48 millimeters
|
Centimeters
|
cm
|
12cm
|
12 centimeters
|
Picas
|
p
|
3p
|
3 picas
|
Points
|
pt
p (before value)
|
6pt
p6
|
6 points
|
Picas and points
|
p (between values)
|
3p6
|
3 picas, 6 points
|
Ciceros
|
c
|
5c
|
5 ciceros
|
Agates
|
ag
|
5ag
|
agates
|