Is It Safe To Use Flexbox, Calc, & Viewport Units?

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Browser Support

Flexbox has nearly 95% support globally and in the US. Sadly, nearly 1.5% of people in the USA are IE8 users. These are users who are likely on Windows XP, an OS which Microsoft has announced EOL on a while back, THEY don't even support it anymore. Not to mention, many of the people on XP using IE8 are large businesses who are really holding back on making the jump. Now do I have to put a large focus on making my site fully functional for the small chance that these select people will even visit it while they are at work? If I'm making a site for a small business, chances are, it's not that big of a deal.

Google has even announced that they are only supporting current version and one version back for their Google Apps moving forward. When they say this, they primarily mean in regards to IE support.

As previously announced, Internet Explorer 11 launched on October 17, 2013, and as a result, we've discontinued support for Internet Explorer 9. Source

That being said, we offer the same support out of the box to our clients. If they need further support, we can supply a separate estimate for that.

Removing Old Support

If you take out IE8 support which is absurd anyway because no major companies support it anymore (Google, Microsoft, etc.) then you have nearly 95% support in the US! The remaining 2-3% being IE9, again, people on old computers and it isn't even officially supported by the big players anymore.

So now ask yourself, is it safe to throw IE8 support out the window at the very least? Looking at my analytic for all sites that I have built within the past 5 months, not even one visit has come from IE8. But then again, keep in mind that I am building sites for small/medium businesses. Your target market is an important factor in this decision. Now with IE8 gone, should we really stunt the growth of flexbox when it pretty much has 95% support globally and in the US?

That's up for you and your company to decide, but I can tell you right now that our company is using flexbox and calc (very similar support to flexbox) in the year of 2015. Especially with Microsoft soon releasing Windows 10 which will come with a new browser (hopefully pushing more people to newer versions of IE or off of IE entirely) and with other rumors of XP users possibly getting free upgrades to Windows 10 or whatever ends up happening, it's ridiculous to continue holding back simply because of IE versions that have been officially announced as EOL for some time now.

What We Support

It's in our contract that we support the current and previous version of the major browsers. That means IE10 and IE11 along with recent versions of Firefox, Chrome, and Safari. As for mobile android browsers, the majority of people (precisely 10% use Chrome for Android over the native Android Browser. But even old versions of this browser have partial support and only add up to a couple percent of overall users).

Is It Safe to Use?

Flexbox support is pretty much identical to calc and vu support. The only problem I have noticed with VU support is that occasionally some mobile browsers do not take kindly to Viewport Height. But even so, it's not so broken that the site is unsable. At the end of the day, it is pretty much supported everywhere. I am loving flexbox and I (like many others) held off on using flexbox for many, many years due to support. The added perk of using it now is that you'd technically be "starting early" and become an expert with it at a time when people are still stuck in the past (and by "early" I am referring to a time in which it already has more than 95% support!).

Examples In Code

The site you are currently on is built entirely on flexbox, calc, and vu. I have moved forward and very happy that I have. Feel free to inspect this site with developer tools to get a better understanding of how these advancements in CSS work or just check out the codepen that I made below.

See the Pen Power of Flexbox, Calc, & Viewport Units by Alex Bass (@flip4bytes) on CodePen.


It's up to your company proposal. We support the current and one version back, just as Google does. We supply a separate estimate if the client wants further support like IE9. Though, 99% of the time, the client is okay with the support we supply and does not request additional browser support. So yes, we are using it moving forward.

Have you used flexbox, calc, or viewport units in any of your projects? If not, what has been holding you back? Let me know in the comments below.

Further Discussion

Updated Sep 10, 2015

If you would like to evolve your business with usability testing and other online marketing solutions, please contact my company, CyberBytes Inc. at (716) 876-1824 and ask for Alex or visit to get a free quote!