How do I set a custom zoom in Chrome?

Update 01-Oct-2015: The Zoom extension suggested by Thomas Ploeger now also works with Google Spreadsheets. Remember to change zoom via extension button 'Z' right to the omnibox, don't try using Ctrl-+/-). If his answer helps you, go ahead and vote for it.

(For Google Spreadsheets specifically, it now has built-in Zoom feature as of 03-Dec-2017).

Another extension not mentioned here is Custom Zoom. Unlike Zoom, it:

1. supports keyboard shortcuts for Zoom In & Zoom Out
2. allows setting custom increment
3. don't have bloated Options that heavily advertise other extensions

Earlier answer (which also still works):

This solution by Ciprian Stan needs elementary HTML skills and need re-doing it every time you restart Google Chrome. But unlike both extensions mentioned here I tried (Zoom and ZoomAll), it works even for Google Docs Spreadsheet--allows truly custom zoom levels.

It affect only zoom levels available for default zoom, but not the zooming increments in Wrench>Zoom or Ctrl-+/- behavior.

Open Settings in Google Chrome.

Inspect the zoom chooser element with the Developer Tools (right click -> Inspect Element). Expand the select and double click on any of the choice values (where you see value="1.1") to edit. Set the value of your choosing (e.g. value="1.15" for 115%). Then select the value from the list (the text may remain the old one, but it doesn't matter). When you close the settings and open them again, you'll find your value.

Background

The devs got a lot of pressure about implementing a built-in default-zoom function. They did implement this in version 10 and reports have confirmed that it works as far back as December, 2010.

Since verve asked this question in August, 2012, either you are using an extremely old version of Chrome (<10), or your browser did (does?) indeed have the function. The same goes for Thomas Ploeger; an extension should not be necessary.

Solution

If you are using an older version, then you need to enable tabbed-options to see the setting, otherwise it is not accessible (figure 2). You can either use the command-line option --enable-tabbed-options or toggle it in about:flags or chrome://flags (figure 3). If you are using a newer version (Chrome ~11+, Chromium ~12+), then tabbed-options is the default setting (actually, the only setting). Look for the the Page Zoom field in chrome://settings under the Web Content section (figure 1).

Work-Around

If you have to use a very old version that does not include tabbed-options at all, then you can try manually entering the setting (before the "exited_cleanly" entry) in the preferences file in your User-Data-Directory. However, there’s two problems with this method. First, (for some reason) the setting uses floating-point numbers instead of a simple integer to represent the zoom-level. This makes it difficult to set it manually, but you can refer to the chart below (table 1). Second, a version that predates the inclusion of tabbed-options at all probably won’t include the default-zoom setting anyway.

Caveats

In any case, you should be aware that the default-zoom setting (currently) only affects pages that you have not already zoomed. Any pages that you have modified the zoom for will not be affected by the new default scaling and will retain the previously assigned zoom setting. This is a nuisance because there is currently no way to modify the list of page/site-specific zoom settings, so you will have to manually set previously-zoomed pages to use the default setting.

Note however that simply zooming a page to 100% is not sufficient to reset the zoom for a page/site. To reset it, you can press Ctrl+Numpad-0 or click the magnifying glass on the toolbar and then click the Reset Zoom button. Another way to reset the zoom is to zoom it to match the current default-zoom setting. For example, if the current default zoom is set to 125% and the page has previously been zoomed to 110%, you must zoom the page to 125% to remove its page-specific setting. (This is actually a bug because if you then change the default zoom to 150%, the page will not retain its 125% zoom!)

Appendices

Figure 1: Default-Zoom setting in newer versions of Chrome

Figure 2: Non-tabbed settings dialog in older version has no default-zoom setting

Figure 3: Enabling tabbed-options in about:flags (or chrome://flags)

Figure 4: Default-Zoom setting in Tabbed-options page of older versions of Chrome

Figure 5: Reset page-zoom to the default setting with the Reset Zoom (in case they fix the bug of zooming to reset)

Table 1: (Non-obvious) values for default-zoom settings in the Preferences file:

 25% :     "default_zoom_level": -7.6035680338478615,
 33% :     "default_zoom_level": -6.0311726618503405,
 50% :     "default_zoom_level": -3.8017840169239308,
 67% :     "default_zoom_level": -2.2293886449264093,
 75% :     "default_zoom_level": -1.5778829311823859,
 90% :     "default_zoom_level": -0.5778829311823857,
100% :     "default_zoom_level": 0.0,
110% :     "default_zoom_level": 0.5227586988632231,
125% :     "default_zoom_level": 1.2239010857415449,
150% :     "default_zoom_level": 2.223901085741545,
175% :     "default_zoom_level": 3.069389038663465,
200% :     "default_zoom_level": 3.8017840169239308,
250% :     "default_zoom_level": 5.025685102665476,
300% :     "default_zoom_level": 6.025685102665476,
400% :     "default_zoom_level": 7.6035680338478615,
500% :     "default_zoom_level": 8.827469119589406,

There is a Google Chrome extension called Zoom which allows you to set custom zoom percentages via a slider, or by entering a certain percentage. It remembers the zoom percentages per website (like Chrome already does, but now you can at least set a custom percentage).

Chrome does not allow you to set a universal zoom setting as far as I am aware. But, to set a universal default zoom for all webpages (again, in a percentage of your choosing), you could use the Zoom All extension.

I would suggest you try these extensions, they might work for you.