The Gmail iOS app clips emails at 20K or more!
The Gmail app for iOS has a nasty habit of "clipping" emails, or cutting their contents short, and adding a button that says "Download entire message." This could potentially hide an email's main content or call to action, but really any extra step a reader has to take is a huge stumbling block to the success of an email campaign. After clicking "Download entire message" the rest of the email appears within the viewing pane.
Note that this kind of clipping is not a problem in the Gmail web app or in the Android version of their mobile app. For other kinds of Gmail clipping, see here.
I sent about a hundred emails to my iPhone’s Gmail app to find the character limit for an email. With no text or other code in the body, I thought this would be a good indication of the maximum size of an email before it gets clipped. I then tested various HTML elements to see if they did or did not count against this limit. I also tested a few images to see how they affected clipping. I wish that I could say I found a perfectly definitive answer on how to prevent this from happening, but I wasn't really able to.
My testing did reveal a number of interesting things about Gmail clipping. I'll discuss them here, but you can just skip down to the table below if you'd rather see the cheat-sheet.
The Gmail app for iOS clips emails at about 20540 characters. This translates to almost exactly 20.0 KB. I say "about" because I also found that this number is inexact. An email that got clipped consistently on one day of testing did not get clipped on later days of testing. This may partly be due to Gmail's post processing. This character count doesn’t include anything that Gmail strips: characters in the <style> block, linked style sheets, comments, classes, and so on. So if you open your latest email campaign and count all of the characters, this number will be a bit larger than the number Gmail is really looking at.
So what kinds of code DOES count towards the limit before getting clipped? Gmail does count meta tags and other elements in the email's head. HTML entities only count as 1 character: the one that is printed. Style tags like <strong> are counted, as well as tags like <br>, <div>, <p> and so on. Images count for more than just their character length, but not for as much as the file size of the picture. This is because image URLs get replaced with a much longer URL (to the address of Gmail's proxy image server), about 170 more characters than they had before.
I also determined that the Gmail app is not just "hiding" the additional content. The rest of the email isn't downloaded until the button is pressed. That would make me think that this is being done to protect mobile users with low data allowances, but my research on pictures contradicts that. When loading an image heavy template, the app downloaded 205 KB worth of data before the clipping occurred. In my text-only test email, the app only downloaded 20 KB before hitting the limit. Because of this, I must conclude that the clipping doesn't take image size into account at all, but instead only allows for a certain amount of code before clipping. That code may contain images of any size.
Check out the quick "cheat sheet" table below.
|About how many characters can I have before my email gets clipped?||20540 characters, or 20 KB|
|Do spaces count against this limit?||Yes|
|Do <br /> tags count against this limit?||Yes|
|Do <p> tags count against this limit?||Yes|
|Do inline styles count against this limit?||Yes|
|Do <head> styles count against this limit?||No|
|Do <meta> tags count against this limit?||Yes|
|Do <strong> tags count against this limit?||Yes|
|Do # characters in inline colors count against this limit?||No|
|Do # characters in body text count against this limit?||Yes|
|Do count as a single character?||Yes|
|Do classes count against this limit?||No|
|Do comments count against this limit?||No|
|Do images count as more than their character count?||Yes. About 170 characters more.|
Can I see this "clipping" in my Email on Acid results?
Because this button triggers on so many emails, we have elected not to show the "Download entire message" button. Instead, we click that button for you and download the rest of the email so that you can preview your whole email without having to take any extra steps.
We decided to create this blog because we noticed how little information there was about clipping in the Gmail app for iOS. We had hoped to be able to provide a quick fix for this problem, hopefully even a way to prevent it from happening, but if such a solution exists we were not able to find it. If you have any more insight into how to disable this annoying message, please let us know in the comments below!