CSS calc() not working in wkhtmltopdf 0.12.4

I am using wkhtmltopdf 0.12.4 (with patched qt) (with node js) to generate my preview pdf of a html.

This works perfectly

<div style="width: 20%;);>
   Test Element
</div>

But this doesn't in wkhtmltopdf (this works well in other browsers)

<div style="width: calc(100% / 5);width: -webkit-calc(100% / 5);>
   Test Element
</div>

Is there any work around for css3 calc() function? Is it supported to my wkhtmltopdf version?